- Email: [email protected]
Cervical cytology screening in two Yorkshire areas: Pattern of service
Publ. Hlth, Lond. (1981)9~, 311-321
Cervical Cytology Screening in T w o Yorkshire Areas: Pattern of Service D. M Parkin M RC.P..MF_CM.
~pec/o/ist in Community Medicine, Leeds A .H.A. (T) W. Collins M.A.
Research Assistant. Leeds A.H.A. (T) and A. D. Clayden Ph.D.
Ser~ior L ecturefin Medical Statistics. University of Leeds The pattern of cervical screening in two areas of Yorkshire in 1976--1977 is described; most women were tested by general practitioners or family planning and cytology clinics, but one third ef tests were from hospital sources, and one third o f women examined were sympt0matie. The known risk factors of low social class and widowed]divorced marital status were associated "with lower than average attendance rates, but attendance during pregnancy or whilst taking oral contraceptives was common. Despite current D.H.S.S. screening policy, the majority of women tested were aged under 35, but an average 5-yearly frequency of attendance was not being achieved, and there were still large numbers of women in the older age-groups receiving first-ever examinations. Introduction
The establishment o f widespread screening f o r cancer o f the cervix was a relatively late development i n much of Britain, a n d only 15 years have elapsed since the first circular announcing plans for a national service was issuedJ The policy then adopted, 5-yearly screening of w o m e n aged 35 .or more (or after three pregnancies), has recently been the subject o f criticism., based largely on increasing mortaKty rates in young women. 2 The current pattern of service is thus 0fconsiderable interest, and this paper examines the nature of the screening programme being delivered to residents of two health authorities' areas in tile north o f England (Leeds and Wakefield)in the 2-year period 1976-1977. Methods
D a t a on cytology tests
M a n y cervical s m e a r s taken for screening purposes are accompanied by form H.M.R. 101/5, a copy o f which is sent t o the N.H.S. central registry where it is filed manually, and acts, after 5 years, t o trigger a recall appointment being sent to the patient. Copies o f the form are retained b y the patient's general practitioner (G,P.) and b y the examining laboratory. However, it was found that many tests carried out, for example those performed in hospital 0033-3506/811060311 + 1 1 $01.00/0
© 1981 The Society of Community Medicine
312
D. M. Parkhl et al.
departments, were not part of this system, and a complete picture of screening activity could only be obtained from the records of laboratories examining the smears; these records therefore formed our sampling frame. A visit was made to all seven pathology laboratories to which specimens might be sent from residents of Leeds and Wakefield A.H.A.sand a 10% random sample of cervical smear tests performed in 1976 and 1977 obtained. Only tests from residents in the two A.H.A.s were included. The information .recorded was that contained on form H.M.R. t01/5 (Figure I), and when the test had not been accompanied by this form, the necessary data had to be obtained :by a retrospective search o f general practitioner and 'hospital records. The informalion was then coded and punched on to 80 column cards 'for computer analysis. Since t h e sample ~consisted o f 1 0 ~ of all tests performed, analysis of the data produces estimates of tests (or attendances) during the 2-year period. Because a proportion o f tests represem repeat examinations o f the same person, a set o f identifying criteria were developed based upon date of birth and place of residence. These allow estimates of numbers of repeat tests to be made. A check on these estimates can be made by utilizing the information collected on the date of the preceding test. The data on repeat examina~ion~ allow estimates to be made of the number of persons examined, as well as the number o f attendances.
Demagraphic data Mid-year estimates of the female population, by age, resident in Leeds and Wakefield in 1976 and 1977 were obtained from O.P.C.S. publications. Estimates of the marital status o f these populations were calculated from the marital rates in the area at.the 1971 census,3 adjusted to take account of trends in the marital composition of the female population o f England and Wales in the period 1971-1976 and .J977.4 ,Published data on social class composition o f the female population at the 1971 census was available for the West Yorkshire conurbation, ~ of which 56% of the female population live in ,the Leeds and Wakefield areas. Data on the number o f maternities in the two areas, by age-group, was obtained from S.D. 52A returns to the Area Hea']th Authorities from O.P.C.S.
Results Leeds and Wakefield A.H.A.s form part of the West Yorkshire conurbation, and had a combined estimated total population in mid-1976 to 1977 of 1,046,000. For cervical cytology testing, the "at risk"" population is females aged 15 or more, a population of 420,650. This study area has a higher incidence of cervical cancer than nationally. The number o f registrations of cancer of cervix (I.C.D. 180) in 1976 to 1977 was 223, a standardized registration ratio based on England and Wales rates for 1974 of 130. In the same 2 years there were 1 ! 1 deaths, an S.M.R. of 121 (based on England and Wales rates for the same period).
Place o f testing A n estimated 97,250 examinations were performed in the 2-year period, and the distribution by place of testing is shown in Table 1. As a group, general practitioners are the source o f the greatest number o f tests (25"5% o f the total), however, for individual practitioners there were wide variations in the number of tests submitted, from none to 560 during the 2 years. Screening was also carried out in 37 special cytology clinics run by directly employed
OR CUPIICCASE
IPATIE +'4T',~ H ~ P I T
2
I
I
I
L
~$P~AI,,,
4
O'~HER 5
I
_J
,,, HOSPITAL
WAflO
CONSULTANT
STATE:--'i"
,
1 I I Figure l,
,
Olher S~mg1oms ~ ~p~iFy~ Bo~ 21)
O
16
~gYCce d ~ t l l m / ¢ e f clno,1111 .i;'1+I ~ u
Negl~V+
Inl~It
? Glandularmo~plame
l~tul ? bw.-si,Pll
5
$
2
Q
4
23 EVID4+NCEOF NEOPLAS;A CYt'OLO¢,+CALPAITC.RN SUGGESTS>
|aunt GYI~oc~',' e+eeO~r
~m-*~*
I~i I . M P
:
~:
. . . . . . .
(
'
'
| POtypt ]M*hgmlntl+
II~r~':;| ' J CetwCibS4
8
2
u
lord
18 NO PE~-VlOU$ T£$1' .P+put,l ~20 AP;~A~A'~CE <3; CE~vtx
17 LAr.T TE~.T
tillday)
4 ; ....
1.
I
*+mtwe
V,+It
+
e
Tf[¢homo~l 2
-
l~m'~'.~'m'+
d-st*
Ji Of l~+f Itlllm,ff+l e
IP4VESTiGATIG~
+
2+ mFLAMMA'~ON ]aa ~URT.tR . . . . . . . . . . . .
-'
21 CLINICAl. DATA (PREVIOUSTREATMENTINCLt~I~G RADIO THERAPY/CHEMOTHEFIApYI
29 I 30 C,m'c[nom,~.~+
_A
(~cdy in Bo~ 211
P~l-~enOplulll + ,l~i~g b
......
Naiional recall s ~ h e m e - form H.M.R, 101/5 (1977).
,,,
2
1
mi3 C;I~~'~+t~l
Int~r-n~nst~ul~bee~l~g 4
O+lchl~t~e Po~,t+COit~tbleedsng
ln~
olhet ~'tm~es
L--J On
#l~.rt~s
:~
I~vo,¢ad
Or) ~11
¢o~ll/a+el~l~v~
~
II,.ICO f=tt~'~
,o,.,++,Shll) ~+,+,,°++, ,,o,,.o,,,, ,+T.+o ~ I~ under 12 week++ 2 TEST I
lhv, ~ d TOlePcf
~1
I
~'~ }11 St.tDE SERIAl., nO.
J W~owedl
Mit+tiZd
•Single
~19 S'¢M~TOM$
107 FIU,~BAND',~0CCUPAilO~|,'ile~l'l if " l I +'mm~'~++m:~,re't* ++M~m*+e+.,~,~wn***,mr c;mer
+.~
IF H O S P I T A L
0~: L A O O ~ T O R Y
10 NA,ME AND ADDRESSITOWN)
MAIOEN NAME.
i !:+ii+;+!°+++
........
F"
FP ~;k|Nl(~ 3
Alia
GP
DAY + i
L
F""
AL
I~mlUltl/llsporl/R~mll Form for Ceevi,~l or Vlelnd Ctrtol~y- UB'. COPY
I"VPE
O F GP
NAME AN0
.
08
-50~JRCE OF st,+Fam
06
r
j DATE OF t I~RTH fold for A t
fold lot B
tFNOT GP
OF SE.;~OEO
~AME AND AODRESS
o3
ADDRESS
FULL POS~'AL
FIRST E A M E S
SUA~A~,E__
u~
Ot
%
(1"0) (2'6) (I.i) (99,9)
420 } 530 2,540 1,080 97,250
* Excludes pregnant and post.natal women,
(25.5) (19,3) (19.6) (I 1.2) 12"3) (16.5 (0.8)
24.800 18,911) 19,040 10.870 2,240 16,030 790
General prac!itiooer Health authorit~ clinics Family planning clinics Ante-natal clinics Post-natal clinics Gynae¢ology out-patients Hospital in-patients Outreach clinics W~N.C.C.C. A.H.A. factory visits Special (V.D.) clinics Private patients Total
(,%)
No,
Place o1"testing
Tests performed
(27.8) (22,0) {19.6) {I 1.7) (2,1) (I i,8) (0.5)
(%)
39"3 25'1 41.8 34,2
35,7 41,2 28.1 25.7 27,8 37.7 37,2
Mean
20,9 54'3 (0) 27,4
88'0 37,5 57'4
32.1 20"4 52.8 02 15"9 18.5 I YO
51'2 28'9 80,9 92"8 87.7 45.0 51'9 40.1
Taking pill
(0} 3.9 4.4
t0)
(O}f
3,0 1"5 13'5 0"2 2,4 4.3
],U.C,D.
Contraception
~'~,under 35
t (0) too few for reliable estimale.
800 (i.01 1.810 [2"2) 1,050 (i.3) 81,890 (I00)
22,800 L8,040 I6,040 9,550 1,730 9,630 440
No.
Age
Persons examined
TABLE !. Cytology lesting 1976-1977: place of examination
54'6 100 33'8
14,3
30-9 17'0 i 5'9 --79.7 80,4
% With symptoms'
2' ,%
'~
.E
J..o
315
Cerricai Cytology: Yorkshire Screening Sc;'vice T^nLE 2. Place of examination and interval between tests
Women reporting pr'~ous
examination(s)
Estimated % of tests which were repeals of those performed in: Place of testing General practitioners AM.A. cylology clinics Family planning clinics Ante-natal clinics Post-nalal clinks Gynaecology clinics Hospital in-patients Outreach clinics } W.N.C.C.C. A.H.A. factory visits Special (V.D.) clinics Private Total
(*/oof tests with interval since last smear)
1976--1977
Y, of examinations with n o previous test: observed (expected)"
< 1~year
25.4 29.9
8.8 4-9 17-5 16.0 26.3 41.4 45.1
33.5 (23.1) 20.8 (19.4) 20.8 (30-2) 13-4 (32-5) 31-0 (28-8) I 1.8 (23-5) t6.1 (23-1)
13.0 5-7 20'3 15.4 46-7 62.6 61-5
31-7 41-4 64.0 57.0 35"0 22.1 3.8
55-3 52.9 15'7 27.6 18.3 15.3 34.6
t'7
10'0
40'5 (22"6)
6"0
48"0
46.0
24-5 1.5 8-5
41-5 10.4 17-5
22.2 (37.6) 20"0 (21"9) 23-9 (23.9)
64.3 25-0 19.5
26-2 25.0 42.4
9.5 50"0 38.1
Same calendar year 3.7 2"2 5.3 6.1 t6.2
1-3 years > 3 years
* "'Expected" pcrcent;~g¢calculated from age-specificrate in Table 3.
A.H.A. staff; these clinics provided 19.3~ of tests and a similar proportion were obtained from 43 A.H.A. family planning clinics. Some special clinics in workplaces (A.H.A. factory visits) and the mobile clinics operated by the Women's .National Cancer Control Campaign (W.N.C.C.C.) provided only 1~ of the tests carried out. About one-third of tests were from various hospital sources; gynaecology out-patient departments (16"5y0), ante-natal and post-natal clinics (13.5y/,), "special treatment" (venereal disease) clinics (2.6~), private patients (1, ! ~ ) and hospital in-patients (0.8 ~).
Interval between tests Identifying data in the sample, and information on time of preceding examination was used to provide estimates of the numbers of women examined. The final estimate of number of" persons tested during the 2-year period was 81,890, and the distribution by place of examination is shown in Table !. The percentage distribution for persons differs from that for. tests, because the interval between examinations is related to the place of testing. Table 2 demonstrates this relationship. Overall 17.5~ of tests were repeat examinations on the same woman within 1976-1977; but the likelihood of a test being such a "repeat" examination varies considerably with the place of testing. The proportion of tests at each place which were first examinations (no previous examination) shows a reciprocal relationship, whh the lowest perce.ntage at gynaecology clinics, and the highest in the "' outreach" mobile and factory el/hies. "ruble 2 also shows, for these women reporting a previous examination, the diafibution of tests by preceding interval. The National Recall Scheme is designed to reminc.:women to re-attend at intervals of 5 years. However, for all except general practitiofier and cytology clinic examinations, most repeat tests were taken within 3 years of the preceding one. The probability of e.:test being a first examination is clearly likely to be related to the subject's age, and the age distribution of attendances and percentage of tests which were
D. M. Park in et al.
316
Txnt~ 3. Attendance for ~tology 1esting in relation to a~e Annual altendance tales (100)
Attendanccs Age
No.
(%)
'~/first attcndances
15-19 20-24 25-29 30-34 35-39 40--49 50--59 60+
6,35~0 17,610 18,000 15o370 11,440 16,250 8,540 3,690
(6.SJ {18-1) 08"5) (15-8) (I 1-8) {t6-7) (8-8) (3-8)
65.8 40.7 23"6 16-6 14.0 15.0 17.1 28-9
6.2 19.4 17.0 9-2 8.8 4-5 2.9 0-04
24 24.-~ .%7,7 21-5 18.7 13-5 7-0 2-4
(~) 3I-6 16"3 10.4 11-8 10-6 3-4 0-8
7,5 22.3 ~1.6 20.0 17.7 12.8 6-3 1.4
All ages
97,250
(100-0)
23-9
8-2
13-5
2-9
10.6
Si~:gle
Married
Widowed/divorced
Total
first enaminations are shown in Table 3. Overall, 23-9~o ofex;mainations were first tests; the highest percentage was seen in the youngest age-group (65-8 ~ of tests on women aged < 20) and the lowest in the age-group 35-39 (14%). However, older women showed somewhat higher races, 28-9 % o f tests on women aged over 60 were ficst examinationS. These age.specific percentages of first visits have been used to calcuk::.~e "expected" proportions o f first examinations at different places. The results are shown in Table 2. This procedure is an indirect age-adjustment, necessary because of the differing age-structure of women attending difficult places. An observed percentage greater than that expected implies ahigher proportion of first tests than would be anticipated from the age structure of the clientele.
Age and marital status Table 3 also shows the average annual rates ofattendance for resident women by age group and marital status. The overall average attendance rate o f 10-6~ is the percentage of women age 15 or more living in the study area having a test in one calendar year. Within this overall rate are large variations by age and marital status. Between 2 0 ~ and 2 5 ~ ofmarried women aged 20-39 attended in 1 year, but attendance rates fall offwi~h age, and are lower for single women and widows/divorcees than for married women. Attendance rates for the 2-year study period can be calculated; these are not double the annual rates (overall attendance rate 1976-1977 is 19-5~ o f women aged 15 or more) since some of the women tested in 1977 will already have been examined in 1976. Because of the effect of such repeat examinations, an average annual examination rate of 20% does not mean that the whole at risk group will be covered after 5 years, With a 5-yearly test policy, however, 20% would represent the minimum attendance rate required to achieve this. Age was strongly associated with the place of testing; the mean age of persons attending, and percentage o f women aged under 35 at each place is shown in Table 1.
Pregnancy and contraception O f the tests, 13"5,% were done during pregnancy, the majority of which (90.7~) were carried out at ante-natal clinics. A further 6.5% of tests were done during the post-natal period, but in this case general practitioners were responsible for the greatest number (47-1%) with post-natal clinics in hospital providing 39.5%. Quite a large proportion of the tests performed in the post-natal period were repeat
Cen,ical Cytology: Yorkshire Screening Sen,ice
317
TABLE4. Cervical ojtology testing assodaled with pregnancy, 1976-1977 Age
No. ofraaternitics
No. of pregnant'3' related tests=
Rate (~/.)
2677 7636 8568 33~9 986 ~7 23,543
1750 5770 6140 3360 970 300 18,290
65 75 72 99 9g (loo) 78
15-19 20-24 25-29 3f~-34 35-39 40--49 Total =
Inc*.~taesalltestson pmgeam women plus post-natai tests where previousexamination was g momhs or rnore
previous,
n= 5850
15--19
~
2 0 - 24
n-- 15~'T60
o g
n= 16,500
25 -- 29
~0-
~
54
~5-39
~
n = t3,850
/
/
40-49
~
~~ tO
20
30
40
50
6G
70
BO 90
n : |O,GO0
n= 15,220
IO0
Percen'l~ge of age greup
Figure 2. Age-group and contraceptive usage. [], Oral contraceptives; I , ].U.C.D.; I-q, nil. or other. examinations of women already tested during pregnancy. Estimates o f the numbers o f tests carried out either during pregnancy or during the post-natal period is shown in Table 4. Comparison with the number o f maternities occurring during 1976-1977 allows calculation o f approximate rates o f testing in relation to pregnancy. In round terms, a cervical smear was performed before or after delivery in two-thirds of women aged 15-19, three quarters aged 20-29, and almost all those aged 30 or more. Overall, 27-49/0 o f the women were taking oral contraceptives at the time o f examination, and 4 - 4 ~ were fitted with I.U.C,D.s. Contraceptive use was closely related to age (Figure 2); I.U.C.D. users were significantly older (mean age 32) than those on oral contraceptives (mean age 28-3; P < 0-001, students t test). There was also an association with place o f
,49. M. Parkin et al.
318
Taat.E 5. Distribulion of subjects by social class lTorces
Social class
I
% of subjects % of female populalion (1971) Mean age (_+s.D,) % of test_~ ~'hich had no prev5ous exami nations
!i
6"1 3.1 34.2 (9) '158
Ill N.M,
11I M
1V
V
studenls
17-9 16.8 33-3 17-4 3-6 4-9 33.7 18.6 6-4 4.8 16.6 16.8 35.2 (10.6) 32-2 (I1-8) 34"2(10'5) 34-7(11-6) 35"i (12-1) 21"5 (4.6) 23-7 22-7 23-7 48 20.2
TAlaLE6. S~'ial class and place of testing (percentage of examinations) Source Social class
Total
G.P.
Cytology clinic
F.P.C.
A.N,C./ P.N,C.
Hospital
Olher
I, I1 111 iV, V Total
25-3 52-7 22-0 100
29"3 48-9 21-8 100
24.4 54-2 21.4 100
28.1 54"2 17.7 100
21-4 52-8 25'g 100
23.8 45-7 30.5 100
18.1 60.8 21.1 100
testing, 5 2 . 8 ~ of persons tested at family planning clinics were on oral contraceptives, as were 54-3~/o at S.T.C.s (Table 1). Social class
Social class for each person attending was derived from the occupation and status of her husband (if married or separated) or her own (if single, widowed or divorced). Because of missing information, it was possible to assign social class to only 6 0 ~ o f subjects; the distribution is shown in Table 5. The social-class distribution of women aged 15 or more in the West Yorkshire conurbation in ! 971 (see Methods) is presented for comparison. The mean age of those attending, and the proportion of,examinations which were first tests, is also shown by social class. Regrouping the social class data into three categories (I + ll; ilI; IV + V)allows comparison of social class with place of testing (Table 6). Statistically signifieatl? fi~. ~;~l!~sinclude an excess of S.C. I and II tests by general practitioners (X2 = 8.58, D.F. -" ~(') and an excess o f S.C. IV and V tests in hospital patients (X" = 10-8, ' ~ and tests from ante- and post-natal clinics (3,2= 7.16, D,F. = 1 ,
S)'mp,
At the time o f testing, 3 0 . 9 ~ o f women reported one or more symptoms. Excluding those examined during pregnancy, or post-natally, this proportion increased to 33-8?/0, and was closely related to place ,of testing (Table I}. Patients with symptoms were, on average, slightly older than those without (mean ages 36-0 v. 33-8, P < 0.001, students t test). The most commonly reported s y m p t o m was vaginal discharge (either alone or with other
Cervical C.l'toh~gy : Yorkshire Scrce~Jh,g Service
319
s)anptoms), which was noted in 43~.gof those with symptoms+ whilst bleeding (intermenstrual+ post coital and post menstrual) was present at the time of testing in 17 .°,~,o f those with sYmptoms. Discussion The method of data collection employed has allowed analysis o f all cytological testing activity in a defined population with an ineidcnce of cervical cancer considerably higher than the national average. Previous reports on the pattern ofcervical smear testing in British populations have usually relied upon data from "'as3nnptomatic screening", 6-g thereby excluding tests done by hospital sources from which over one third o f our specimens come. Quite a high proportion of hospital specimens were from symptomatic women, and were often recent repeat examinations o f tests performed elsewhere, but they also included many specimens taken during pregnancy or ill the early post-natal period. Conversely, not all tests from the major sources (general practitioners, family planning and cytology clinics) were on asymptomatic women; 30.9.% o f women tested by general practitioners reported one or more symptoms. Nationally collected statistics are derived by sampling the records o f tests taken as part of the national recall scheme and hence notified to the N.H.S. Central Register. The data thus excludes examinations not so notifed (almost all hospital tests), and since data collection and retrieval is not automated, only very" limited information is available. ~" The D.H.S.S. proposes to aboli:,h the National Recall Scheme since, it is claimed, less than 20~o of the documents generated achieve a response." The impossibility ofensuring that no recall is initiated within 5 years when at least one-third of examinati0ns are not notified makes this unsurprising. Furthermore many family planning clinics operate informal schemes o f their own, since the Family Planning Association, who operated them before 1974, recommended smears at 3-yearly intervals. Despite current national policy recommending regular examination for those aged 35 or more, the majority of women examined (57.4~) were younger than this. Many of these young women were tested at family planning clinics, and it is also apparent that almost all women are tested before or after childbirth. However, there are also significant numbers o f young women being tested by general practitioners and cytology clinics. This age distribution was lower than reported in the Manchesti:r area in .]967-19707 and in N.E. Scotland in 1958-1974) 2 but is the same as the 57-4~ of tests on women aged under 35 reported under the national recall scheme in 1967/77 for England and Wales) ° At a Brighton laboratory in 1974-1975, 63,% of women examined were aged under 35, but there much of the work was from family planning clinics) ~ It would seem, therefore, that as far as the recent anxiety to see screening extended to younger age groups is conoerned, 33-a~ the pi'actical outcome of current D.H.S.S. policy might be considered satisfactory. A more legitimate cause for concern is the frequency o f screening being achieved; the current study suggests that an average frequency of 5-yearly testing is not being attained; calculations on a similar basis using England and Wales data ~° are no more reassuring. Although the smear test has been available for many years, a high proportion of tests, even in the older age-groups, were first examinations. This suggests that at that time (1976-1977) there remained in the population quite a large percentage o f women who had never been screened (compare Aberdeen, where 90,% coverage of the female population was claimed as early as 1971~*). Two sources in particular, general practitioners and the "outreach'" clinics (A.H.A. factory visits and the W.N.C.C.C. mobile clinics) appeared to be successful in recruiting first attenders. However, since the degree to which data on previous examinations is based on memory may vary by place of testing, possible bias due to inadequate recall requires consideration. ~7
320
D. M. Parkin et aL
Attendance rates by marital status indicate that married women are more likely to be tested, an excess atlendanee rate partly explained by testing during pregnancy and at family-planning clinics. The groups most at risk from cancer o f the cervix, lhose formerly married, ts have the lowest attendance rates. The proporlion ofthe female populati on cu'rre ntly using different methods of contraception is unknown, and this prex:ludes calculalion of attendance rates. However, the high proportion of attenders in the younger age groups on oral contraception suggests that this is a group with higher than average screening attendance. As already noted, many family planning clinics encourage reguiar retesting of their clientele more frequently than St-yearly. The aetioiogical role of oral contraceptives in cervical cancer is controversial, but c u r r e m evidence suggest that any excess risk is indirect via other social or sexual factors) ~ The data on social class require cautious interpretation, since 4 0 ~ o f tests were unclassified (at the ! 971 census, 209o~o f w o m e n aged 15 + were similarly unclassified). However, the data d o suggest that the utilization o f this ser~,ice is related to social class; there was a higher tharl expected proportion o f attenders, and lower than average proportion o f first tests, in social classes I and II than IV and V. However, the ~arge social class disparities in attendance noted by others :.s appear less marked in Leeds and Wakefield. This may in part be due t o the inclusion o f data from hospital and pregnancy-related sources, where the proportion o f women in social classes I V and V is higher than expected. The different social class make u p of clients of general practitioners, family planning and cytology clinics, were similar to, but less marked, than those reported in Manchester.: Nevertheless, there is still under representation in the screening programme o f those social groups most at risk of cervical cancer. 2o Acknowledgments This work was supported by a grant from the D.H,S.S.; however, the views expressed are not necessarily those o f the Department. We wo~ld like to thank the Yorkshire Regional Cancer Organisation for advice and support and the consultants, general practitioners and clinical medical o~cers in Leeds and Wakefield for assi.qing us with the collection of data from clinical records.
References 1. Minislry of Health (1966). Population screening for cancer of the cervix Circular 18/66 {H.M. (66) 76]. 2. Parkin, D. M. & Clayden, A. D. (1980). Screening for cancer of the cervix. British Medical Journal !i, 1566. 3. O.P.C.S. (1973). Census 1971 : England and Wales county reports: Yorkshire (W. Riding), Part l, ti.M.S.O. 4. O.P.C.$. (1979). Marriage and divorce statistics, series FM2, 4. H.M.:S.O. 5. 0.P.C.S. (1975). Census 1971 : Economic activity, part tv (10% sample). H.M.S.O. 6, Sansom, C. D., WakefieId, J, & Yule, R. (1970.). Cervical cytology in the Manchester region: changing pattern of respollse. Medical Officer 123. 357-9. 7. Sansom, C. D., Wakefield, J. & Yule, R. {.i971). Trends in cytological screening in lhe Manchester area i965-1971. Cornmunity Medicine, 26, 253-7. 8. Tho.rnson, J. G. (1971). Cervical cytology in England and Wales: some facts. Health Trends 3, 24-5. 9. Kent, H. M. (1974). Cervical cytologT in Hertfordshire, Public Health gS, 275-288. 10. D.H.S.S. (1980). Health and personal social services statistics 1978 (Table 10.4). H.M.S.O. I1. D.H.S.S. (1981). Health service development: cervical cytology recall scheme. H.N. (81) 14. 12. McGregor, J. E. (1976). Evaluation of mass screening programmes for cervical cancer in N.E. Scotland. T1anori 62, 287-95.
Cervical Cytology: Yorkshire Screening Service
321
13. Andrews, F. J., Linehan. J. J. & Melcher, D. H. (1978). Cervical cancer in younger women. Lancet ii, 776-8. 14. Yule, R. (1978). Mortality from carcinoma of the cervix. Lances i, 1051-2. 15. Cotton, R. (1980). Why D.H.S.S. screening policy puts young women unnecessarily at risk. World Medicine 15, 21-6. 16. McGregor, J. E., Fraser, M. E. & Mann, E. M. F. 0971). Improved prognosis ofcervical cancer due to comprehensive screening. Lancet i, 74-6. 17. Wakefield, J. & Baric, L. (1965). Public and professional attitudes to a screening programme for the prevention of cancer of lhe uterine cervix: a preliminary study. British Journal o f Preventive and Social Medicine 19, 151-8. 18, Leck. I., Sibary, K. & Wakefield, J. (i 978). Incidence ofcervicai cancer by marital status. Journal of Epidemiology and Community Health 32, 108-10. 19. The Walton Report (1976). Cervical cancer screening programs. 1. Epidemiology and natural history of carcinoma of the cervix. Canadian Medical Association Journal 114, 1003-12. 20. Beral, V. (1974). Cancer of the cervix: A sexually transmitted infection'?. Lancet L 1037-40.
Cervical Cytology Screening in T w o Yorkshire Areas: Pattern of Service D. M Parkin M RC.P..MF_CM.
~pec/o/ist in Community Medicine, Leeds A .H.A. (T) W. Collins M.A.
Research Assistant. Leeds A.H.A. (T) and A. D. Clayden Ph.D.
Ser~ior L ecturefin Medical Statistics. University of Leeds The pattern of cervical screening in two areas of Yorkshire in 1976--1977 is described; most women were tested by general practitioners or family planning and cytology clinics, but one third ef tests were from hospital sources, and one third o f women examined were sympt0matie. The known risk factors of low social class and widowed]divorced marital status were associated "with lower than average attendance rates, but attendance during pregnancy or whilst taking oral contraceptives was common. Despite current D.H.S.S. screening policy, the majority of women tested were aged under 35, but an average 5-yearly frequency of attendance was not being achieved, and there were still large numbers of women in the older age-groups receiving first-ever examinations. Introduction
The establishment o f widespread screening f o r cancer o f the cervix was a relatively late development i n much of Britain, a n d only 15 years have elapsed since the first circular announcing plans for a national service was issuedJ The policy then adopted, 5-yearly screening of w o m e n aged 35 .or more (or after three pregnancies), has recently been the subject o f criticism., based largely on increasing mortaKty rates in young women. 2 The current pattern of service is thus 0fconsiderable interest, and this paper examines the nature of the screening programme being delivered to residents of two health authorities' areas in tile north o f England (Leeds and Wakefield)in the 2-year period 1976-1977. Methods
D a t a on cytology tests
M a n y cervical s m e a r s taken for screening purposes are accompanied by form H.M.R. 101/5, a copy o f which is sent t o the N.H.S. central registry where it is filed manually, and acts, after 5 years, t o trigger a recall appointment being sent to the patient. Copies o f the form are retained b y the patient's general practitioner (G,P.) and b y the examining laboratory. However, it was found that many tests carried out, for example those performed in hospital 0033-3506/811060311 + 1 1 $01.00/0
© 1981 The Society of Community Medicine
312
D. M. Parkhl et al.
departments, were not part of this system, and a complete picture of screening activity could only be obtained from the records of laboratories examining the smears; these records therefore formed our sampling frame. A visit was made to all seven pathology laboratories to which specimens might be sent from residents of Leeds and Wakefield A.H.A.sand a 10% random sample of cervical smear tests performed in 1976 and 1977 obtained. Only tests from residents in the two A.H.A.s were included. The information .recorded was that contained on form H.M.R. t01/5 (Figure I), and when the test had not been accompanied by this form, the necessary data had to be obtained :by a retrospective search o f general practitioner and 'hospital records. The informalion was then coded and punched on to 80 column cards 'for computer analysis. Since t h e sample ~consisted o f 1 0 ~ of all tests performed, analysis of the data produces estimates of tests (or attendances) during the 2-year period. Because a proportion o f tests represem repeat examinations o f the same person, a set o f identifying criteria were developed based upon date of birth and place of residence. These allow estimates of numbers of repeat tests to be made. A check on these estimates can be made by utilizing the information collected on the date of the preceding test. The data on repeat examina~ion~ allow estimates to be made of the number of persons examined, as well as the number o f attendances.
Demagraphic data Mid-year estimates of the female population, by age, resident in Leeds and Wakefield in 1976 and 1977 were obtained from O.P.C.S. publications. Estimates of the marital status o f these populations were calculated from the marital rates in the area at.the 1971 census,3 adjusted to take account of trends in the marital composition of the female population o f England and Wales in the period 1971-1976 and .J977.4 ,Published data on social class composition o f the female population at the 1971 census was available for the West Yorkshire conurbation, ~ of which 56% of the female population live in ,the Leeds and Wakefield areas. Data on the number o f maternities in the two areas, by age-group, was obtained from S.D. 52A returns to the Area Hea']th Authorities from O.P.C.S.
Results Leeds and Wakefield A.H.A.s form part of the West Yorkshire conurbation, and had a combined estimated total population in mid-1976 to 1977 of 1,046,000. For cervical cytology testing, the "at risk"" population is females aged 15 or more, a population of 420,650. This study area has a higher incidence of cervical cancer than nationally. The number o f registrations of cancer of cervix (I.C.D. 180) in 1976 to 1977 was 223, a standardized registration ratio based on England and Wales rates for 1974 of 130. In the same 2 years there were 1 ! 1 deaths, an S.M.R. of 121 (based on England and Wales rates for the same period).
Place o f testing A n estimated 97,250 examinations were performed in the 2-year period, and the distribution by place of testing is shown in Table 1. As a group, general practitioners are the source o f the greatest number o f tests (25"5% o f the total), however, for individual practitioners there were wide variations in the number of tests submitted, from none to 560 during the 2 years. Screening was also carried out in 37 special cytology clinics run by directly employed
OR CUPIICCASE
IPATIE +'4T',~ H ~ P I T
2
I
I
I
L
~$P~AI,,,
4
O'~HER 5
I
_J
,,, HOSPITAL
WAflO
CONSULTANT
STATE:--'i"
,
1 I I Figure l,
,
Olher S~mg1oms ~ ~p~iFy~ Bo~ 21)
O
16
~gYCce d ~ t l l m / ¢ e f clno,1111 .i;'1+I ~ u
Negl~V+
Inl~It
? Glandularmo~plame
l~tul ? bw.-si,Pll
5
$
2
Q
4
23 EVID4+NCEOF NEOPLAS;A CYt'OLO¢,+CALPAITC.RN SUGGESTS>
|aunt GYI~oc~',' e+eeO~r
~m-*~*
I~i I . M P
:
~:
. . . . . . .
(
'
'
| POtypt ]M*hgmlntl+
II~r~':;| ' J CetwCibS4
8
2
u
lord
18 NO PE~-VlOU$ T£$1' .P+put,l ~20 AP;~A~A'~CE <3; CE~vtx
17 LAr.T TE~.T
tillday)
4 ; ....
1.
I
*+mtwe
V,+It
+
e
Tf[¢homo~l 2
-
l~m'~'.~'m'+
d-st*
Ji Of l~+f Itlllm,ff+l e
IP4VESTiGATIG~
+
2+ mFLAMMA'~ON ]aa ~URT.tR . . . . . . . . . . . .
-'
21 CLINICAl. DATA (PREVIOUSTREATMENTINCLt~I~G RADIO THERAPY/CHEMOTHEFIApYI
29 I 30 C,m'c[nom,~.~+
_A
(~cdy in Bo~ 211
P~l-~enOplulll + ,l~i~g b
......
Naiional recall s ~ h e m e - form H.M.R, 101/5 (1977).
,,,
2
1
mi3 C;I~~'~+t~l
Int~r-n~nst~ul~bee~l~g 4
O+lchl~t~e Po~,t+COit~tbleedsng
ln~
olhet ~'tm~es
L--J On
#l~.rt~s
:~
I~vo,¢ad
Or) ~11
¢o~ll/a+el~l~v~
~
II,.ICO f=tt~'~
,o,.,++,Shll) ~+,+,,°++, ,,o,,.o,,,, ,+T.+o ~ I~ under 12 week++ 2 TEST I
lhv, ~ d TOlePcf
~1
I
~'~ }11 St.tDE SERIAl., nO.
J W~owedl
Mit+tiZd
•Single
~19 S'¢M~TOM$
107 FIU,~BAND',~0CCUPAilO~|,'ile~l'l if " l I +'mm~'~++m:~,re't* ++M~m*+e+.,~,~wn***,mr c;mer
+.~
IF H O S P I T A L
0~: L A O O ~ T O R Y
10 NA,ME AND ADDRESSITOWN)
MAIOEN NAME.
i !:+ii+;+!°+++
........
F"
FP ~;k|Nl(~ 3
Alia
GP
DAY + i
L
F""
AL
I~mlUltl/llsporl/R~mll Form for Ceevi,~l or Vlelnd Ctrtol~y- UB'. COPY
I"VPE
O F GP
NAME AN0
.
08
-50~JRCE OF st,+Fam
06
r
j DATE OF t I~RTH fold for A t
fold lot B
tFNOT GP
OF SE.;~OEO
~AME AND AODRESS
o3
ADDRESS
FULL POS~'AL
FIRST E A M E S
SUA~A~,E__
u~
Ot
%
(1"0) (2'6) (I.i) (99,9)
420 } 530 2,540 1,080 97,250
* Excludes pregnant and post.natal women,
(25.5) (19,3) (19.6) (I 1.2) 12"3) (16.5 (0.8)
24.800 18,911) 19,040 10.870 2,240 16,030 790
General prac!itiooer Health authorit~ clinics Family planning clinics Ante-natal clinics Post-natal clinics Gynae¢ology out-patients Hospital in-patients Outreach clinics W~N.C.C.C. A.H.A. factory visits Special (V.D.) clinics Private patients Total
(,%)
No,
Place o1"testing
Tests performed
(27.8) (22,0) {19.6) {I 1.7) (2,1) (I i,8) (0.5)
(%)
39"3 25'1 41.8 34,2
35,7 41,2 28.1 25.7 27,8 37.7 37,2
Mean
20,9 54'3 (0) 27,4
88'0 37,5 57'4
32.1 20"4 52.8 02 15"9 18.5 I YO
51'2 28'9 80,9 92"8 87.7 45.0 51'9 40.1
Taking pill
(0} 3.9 4.4
t0)
(O}f
3,0 1"5 13'5 0"2 2,4 4.3
],U.C,D.
Contraception
~'~,under 35
t (0) too few for reliable estimale.
800 (i.01 1.810 [2"2) 1,050 (i.3) 81,890 (I00)
22,800 L8,040 I6,040 9,550 1,730 9,630 440
No.
Age
Persons examined
TABLE !. Cytology lesting 1976-1977: place of examination
54'6 100 33'8
14,3
30-9 17'0 i 5'9 --79.7 80,4
% With symptoms'
2' ,%
'~
.E
J..o
315
Cerricai Cytology: Yorkshire Screening Sc;'vice T^nLE 2. Place of examination and interval between tests
Women reporting pr'~ous
examination(s)
Estimated % of tests which were repeals of those performed in: Place of testing General practitioners AM.A. cylology clinics Family planning clinics Ante-natal clinics Post-nalal clinks Gynaecology clinics Hospital in-patients Outreach clinics } W.N.C.C.C. A.H.A. factory visits Special (V.D.) clinics Private Total
(*/oof tests with interval since last smear)
1976--1977
Y, of examinations with n o previous test: observed (expected)"
< 1~year
25.4 29.9
8.8 4-9 17-5 16.0 26.3 41.4 45.1
33.5 (23.1) 20.8 (19.4) 20.8 (30-2) 13-4 (32-5) 31-0 (28-8) I 1.8 (23-5) t6.1 (23-1)
13.0 5-7 20'3 15.4 46-7 62.6 61-5
31-7 41-4 64.0 57.0 35"0 22.1 3.8
55-3 52.9 15'7 27.6 18.3 15.3 34.6
t'7
10'0
40'5 (22"6)
6"0
48"0
46.0
24-5 1.5 8-5
41-5 10.4 17-5
22.2 (37.6) 20"0 (21"9) 23-9 (23.9)
64.3 25-0 19.5
26-2 25.0 42.4
9.5 50"0 38.1
Same calendar year 3.7 2"2 5.3 6.1 t6.2
1-3 years > 3 years
* "'Expected" pcrcent;~g¢calculated from age-specificrate in Table 3.
A.H.A. staff; these clinics provided 19.3~ of tests and a similar proportion were obtained from 43 A.H.A. family planning clinics. Some special clinics in workplaces (A.H.A. factory visits) and the mobile clinics operated by the Women's .National Cancer Control Campaign (W.N.C.C.C.) provided only 1~ of the tests carried out. About one-third of tests were from various hospital sources; gynaecology out-patient departments (16"5y0), ante-natal and post-natal clinics (13.5y/,), "special treatment" (venereal disease) clinics (2.6~), private patients (1, ! ~ ) and hospital in-patients (0.8 ~).
Interval between tests Identifying data in the sample, and information on time of preceding examination was used to provide estimates of the numbers of women examined. The final estimate of number of" persons tested during the 2-year period was 81,890, and the distribution by place of examination is shown in Table !. The percentage distribution for persons differs from that for. tests, because the interval between examinations is related to the place of testing. Table 2 demonstrates this relationship. Overall 17.5~ of tests were repeat examinations on the same woman within 1976-1977; but the likelihood of a test being such a "repeat" examination varies considerably with the place of testing. The proportion of tests at each place which were first examinations (no previous examination) shows a reciprocal relationship, whh the lowest perce.ntage at gynaecology clinics, and the highest in the "' outreach" mobile and factory el/hies. "ruble 2 also shows, for these women reporting a previous examination, the diafibution of tests by preceding interval. The National Recall Scheme is designed to reminc.:women to re-attend at intervals of 5 years. However, for all except general practitiofier and cytology clinic examinations, most repeat tests were taken within 3 years of the preceding one. The probability of e.:test being a first examination is clearly likely to be related to the subject's age, and the age distribution of attendances and percentage of tests which were
D. M. Park in et al.
316
Txnt~ 3. Attendance for ~tology 1esting in relation to a~e Annual altendance tales (100)
Attendanccs Age
No.
(%)
'~/first attcndances
15-19 20-24 25-29 30-34 35-39 40--49 50--59 60+
6,35~0 17,610 18,000 15o370 11,440 16,250 8,540 3,690
(6.SJ {18-1) 08"5) (15-8) (I 1-8) {t6-7) (8-8) (3-8)
65.8 40.7 23"6 16-6 14.0 15.0 17.1 28-9
6.2 19.4 17.0 9-2 8.8 4-5 2.9 0-04
24 24.-~ .%7,7 21-5 18.7 13-5 7-0 2-4
(~) 3I-6 16"3 10.4 11-8 10-6 3-4 0-8
7,5 22.3 ~1.6 20.0 17.7 12.8 6-3 1.4
All ages
97,250
(100-0)
23-9
8-2
13-5
2-9
10.6
Si~:gle
Married
Widowed/divorced
Total
first enaminations are shown in Table 3. Overall, 23-9~o ofex;mainations were first tests; the highest percentage was seen in the youngest age-group (65-8 ~ of tests on women aged < 20) and the lowest in the age-group 35-39 (14%). However, older women showed somewhat higher races, 28-9 % o f tests on women aged over 60 were ficst examinationS. These age.specific percentages of first visits have been used to calcuk::.~e "expected" proportions o f first examinations at different places. The results are shown in Table 2. This procedure is an indirect age-adjustment, necessary because of the differing age-structure of women attending difficult places. An observed percentage greater than that expected implies ahigher proportion of first tests than would be anticipated from the age structure of the clientele.
Age and marital status Table 3 also shows the average annual rates ofattendance for resident women by age group and marital status. The overall average attendance rate o f 10-6~ is the percentage of women age 15 or more living in the study area having a test in one calendar year. Within this overall rate are large variations by age and marital status. Between 2 0 ~ and 2 5 ~ ofmarried women aged 20-39 attended in 1 year, but attendance rates fall offwi~h age, and are lower for single women and widows/divorcees than for married women. Attendance rates for the 2-year study period can be calculated; these are not double the annual rates (overall attendance rate 1976-1977 is 19-5~ o f women aged 15 or more) since some of the women tested in 1977 will already have been examined in 1976. Because of the effect of such repeat examinations, an average annual examination rate of 20% does not mean that the whole at risk group will be covered after 5 years, With a 5-yearly test policy, however, 20% would represent the minimum attendance rate required to achieve this. Age was strongly associated with the place of testing; the mean age of persons attending, and percentage o f women aged under 35 at each place is shown in Table 1.
Pregnancy and contraception O f the tests, 13"5,% were done during pregnancy, the majority of which (90.7~) were carried out at ante-natal clinics. A further 6.5% of tests were done during the post-natal period, but in this case general practitioners were responsible for the greatest number (47-1%) with post-natal clinics in hospital providing 39.5%. Quite a large proportion of the tests performed in the post-natal period were repeat
Cen,ical Cytology: Yorkshire Screening Sen,ice
317
TABLE4. Cervical ojtology testing assodaled with pregnancy, 1976-1977 Age
No. ofraaternitics
No. of pregnant'3' related tests=
Rate (~/.)
2677 7636 8568 33~9 986 ~7 23,543
1750 5770 6140 3360 970 300 18,290
65 75 72 99 9g (loo) 78
15-19 20-24 25-29 3f~-34 35-39 40--49 Total =
Inc*.~taesalltestson pmgeam women plus post-natai tests where previousexamination was g momhs or rnore
previous,
n= 5850
15--19
~
2 0 - 24
n-- 15~'T60
o g
n= 16,500
25 -- 29
~0-
~
54
~5-39
~
n = t3,850
/
/
40-49
~
~~ tO
20
30
40
50
6G
70
BO 90
n : |O,GO0
n= 15,220
IO0
Percen'l~ge of age greup
Figure 2. Age-group and contraceptive usage. [], Oral contraceptives; I , ].U.C.D.; I-q, nil. or other. examinations of women already tested during pregnancy. Estimates o f the numbers o f tests carried out either during pregnancy or during the post-natal period is shown in Table 4. Comparison with the number o f maternities occurring during 1976-1977 allows calculation o f approximate rates o f testing in relation to pregnancy. In round terms, a cervical smear was performed before or after delivery in two-thirds of women aged 15-19, three quarters aged 20-29, and almost all those aged 30 or more. Overall, 27-49/0 o f the women were taking oral contraceptives at the time o f examination, and 4 - 4 ~ were fitted with I.U.C,D.s. Contraceptive use was closely related to age (Figure 2); I.U.C.D. users were significantly older (mean age 32) than those on oral contraceptives (mean age 28-3; P < 0-001, students t test). There was also an association with place o f
,49. M. Parkin et al.
318
Taat.E 5. Distribulion of subjects by social class lTorces
Social class
I
% of subjects % of female populalion (1971) Mean age (_+s.D,) % of test_~ ~'hich had no prev5ous exami nations
!i
6"1 3.1 34.2 (9) '158
Ill N.M,
11I M
1V
V
studenls
17-9 16.8 33-3 17-4 3-6 4-9 33.7 18.6 6-4 4.8 16.6 16.8 35.2 (10.6) 32-2 (I1-8) 34"2(10'5) 34-7(11-6) 35"i (12-1) 21"5 (4.6) 23-7 22-7 23-7 48 20.2
TAlaLE6. S~'ial class and place of testing (percentage of examinations) Source Social class
Total
G.P.
Cytology clinic
F.P.C.
A.N,C./ P.N,C.
Hospital
Olher
I, I1 111 iV, V Total
25-3 52-7 22-0 100
29"3 48-9 21-8 100
24.4 54-2 21.4 100
28.1 54"2 17.7 100
21-4 52-8 25'g 100
23.8 45-7 30.5 100
18.1 60.8 21.1 100
testing, 5 2 . 8 ~ of persons tested at family planning clinics were on oral contraceptives, as were 54-3~/o at S.T.C.s (Table 1). Social class
Social class for each person attending was derived from the occupation and status of her husband (if married or separated) or her own (if single, widowed or divorced). Because of missing information, it was possible to assign social class to only 6 0 ~ o f subjects; the distribution is shown in Table 5. The social-class distribution of women aged 15 or more in the West Yorkshire conurbation in ! 971 (see Methods) is presented for comparison. The mean age of those attending, and the proportion of,examinations which were first tests, is also shown by social class. Regrouping the social class data into three categories (I + ll; ilI; IV + V)allows comparison of social class with place of testing (Table 6). Statistically signifieatl? fi~. ~;~l!~sinclude an excess of S.C. I and II tests by general practitioners (X2 = 8.58, D.F. -" ~(') and an excess o f S.C. IV and V tests in hospital patients (X" = 10-8, ' ~ and tests from ante- and post-natal clinics (3,2= 7.16, D,F. = 1 ,
S)'mp,
At the time o f testing, 3 0 . 9 ~ o f women reported one or more symptoms. Excluding those examined during pregnancy, or post-natally, this proportion increased to 33-8?/0, and was closely related to place ,of testing (Table I}. Patients with symptoms were, on average, slightly older than those without (mean ages 36-0 v. 33-8, P < 0.001, students t test). The most commonly reported s y m p t o m was vaginal discharge (either alone or with other
Cervical C.l'toh~gy : Yorkshire Scrce~Jh,g Service
319
s)anptoms), which was noted in 43~.gof those with symptoms+ whilst bleeding (intermenstrual+ post coital and post menstrual) was present at the time of testing in 17 .°,~,o f those with sYmptoms. Discussion The method of data collection employed has allowed analysis o f all cytological testing activity in a defined population with an ineidcnce of cervical cancer considerably higher than the national average. Previous reports on the pattern ofcervical smear testing in British populations have usually relied upon data from "'as3nnptomatic screening", 6-g thereby excluding tests done by hospital sources from which over one third o f our specimens come. Quite a high proportion of hospital specimens were from symptomatic women, and were often recent repeat examinations o f tests performed elsewhere, but they also included many specimens taken during pregnancy or ill the early post-natal period. Conversely, not all tests from the major sources (general practitioners, family planning and cytology clinics) were on asymptomatic women; 30.9.% o f women tested by general practitioners reported one or more symptoms. Nationally collected statistics are derived by sampling the records o f tests taken as part of the national recall scheme and hence notified to the N.H.S. Central Register. The data thus excludes examinations not so notifed (almost all hospital tests), and since data collection and retrieval is not automated, only very" limited information is available. ~" The D.H.S.S. proposes to aboli:,h the National Recall Scheme since, it is claimed, less than 20~o of the documents generated achieve a response." The impossibility ofensuring that no recall is initiated within 5 years when at least one-third of examinati0ns are not notified makes this unsurprising. Furthermore many family planning clinics operate informal schemes o f their own, since the Family Planning Association, who operated them before 1974, recommended smears at 3-yearly intervals. Despite current national policy recommending regular examination for those aged 35 or more, the majority of women examined (57.4~) were younger than this. Many of these young women were tested at family planning clinics, and it is also apparent that almost all women are tested before or after childbirth. However, there are also significant numbers o f young women being tested by general practitioners and cytology clinics. This age distribution was lower than reported in the Manchesti:r area in .]967-19707 and in N.E. Scotland in 1958-1974) 2 but is the same as the 57-4~ of tests on women aged under 35 reported under the national recall scheme in 1967/77 for England and Wales) ° At a Brighton laboratory in 1974-1975, 63,% of women examined were aged under 35, but there much of the work was from family planning clinics) ~ It would seem, therefore, that as far as the recent anxiety to see screening extended to younger age groups is conoerned, 33-a~ the pi'actical outcome of current D.H.S.S. policy might be considered satisfactory. A more legitimate cause for concern is the frequency o f screening being achieved; the current study suggests that an average frequency of 5-yearly testing is not being attained; calculations on a similar basis using England and Wales data ~° are no more reassuring. Although the smear test has been available for many years, a high proportion of tests, even in the older age-groups, were first examinations. This suggests that at that time (1976-1977) there remained in the population quite a large percentage o f women who had never been screened (compare Aberdeen, where 90,% coverage of the female population was claimed as early as 1971~*). Two sources in particular, general practitioners and the "outreach'" clinics (A.H.A. factory visits and the W.N.C.C.C. mobile clinics) appeared to be successful in recruiting first attenders. However, since the degree to which data on previous examinations is based on memory may vary by place of testing, possible bias due to inadequate recall requires consideration. ~7
320
D. M. Parkin et aL
Attendance rates by marital status indicate that married women are more likely to be tested, an excess atlendanee rate partly explained by testing during pregnancy and at family-planning clinics. The groups most at risk from cancer o f the cervix, lhose formerly married, ts have the lowest attendance rates. The proporlion ofthe female populati on cu'rre ntly using different methods of contraception is unknown, and this prex:ludes calculalion of attendance rates. However, the high proportion of attenders in the younger age groups on oral contraception suggests that this is a group with higher than average screening attendance. As already noted, many family planning clinics encourage reguiar retesting of their clientele more frequently than St-yearly. The aetioiogical role of oral contraceptives in cervical cancer is controversial, but c u r r e m evidence suggest that any excess risk is indirect via other social or sexual factors) ~ The data on social class require cautious interpretation, since 4 0 ~ o f tests were unclassified (at the ! 971 census, 209o~o f w o m e n aged 15 + were similarly unclassified). However, the data d o suggest that the utilization o f this ser~,ice is related to social class; there was a higher tharl expected proportion o f attenders, and lower than average proportion o f first tests, in social classes I and II than IV and V. However, the ~arge social class disparities in attendance noted by others :.s appear less marked in Leeds and Wakefield. This may in part be due t o the inclusion o f data from hospital and pregnancy-related sources, where the proportion o f women in social classes I V and V is higher than expected. The different social class make u p of clients of general practitioners, family planning and cytology clinics, were similar to, but less marked, than those reported in Manchester.: Nevertheless, there is still under representation in the screening programme o f those social groups most at risk of cervical cancer. 2o Acknowledgments This work was supported by a grant from the D.H,S.S.; however, the views expressed are not necessarily those o f the Department. We wo~ld like to thank the Yorkshire Regional Cancer Organisation for advice and support and the consultants, general practitioners and clinical medical o~cers in Leeds and Wakefield for assi.qing us with the collection of data from clinical records.
References 1. Minislry of Health (1966). Population screening for cancer of the cervix Circular 18/66 {H.M. (66) 76]. 2. Parkin, D. M. & Clayden, A. D. (1980). Screening for cancer of the cervix. British Medical Journal !i, 1566. 3. O.P.C.S. (1973). Census 1971 : England and Wales county reports: Yorkshire (W. Riding), Part l, ti.M.S.O. 4. O.P.C.$. (1979). Marriage and divorce statistics, series FM2, 4. H.M.:S.O. 5. 0.P.C.S. (1975). Census 1971 : Economic activity, part tv (10% sample). H.M.S.O. 6, Sansom, C. D., WakefieId, J, & Yule, R. (1970.). Cervical cytology in the Manchester region: changing pattern of respollse. Medical Officer 123. 357-9. 7. Sansom, C. D., Wakefield, J. & Yule, R. {.i971). Trends in cytological screening in lhe Manchester area i965-1971. Cornmunity Medicine, 26, 253-7. 8. Tho.rnson, J. G. (1971). Cervical cytology in England and Wales: some facts. Health Trends 3, 24-5. 9. Kent, H. M. (1974). Cervical cytologT in Hertfordshire, Public Health gS, 275-288. 10. D.H.S.S. (1980). Health and personal social services statistics 1978 (Table 10.4). H.M.S.O. I1. D.H.S.S. (1981). Health service development: cervical cytology recall scheme. H.N. (81) 14. 12. McGregor, J. E. (1976). Evaluation of mass screening programmes for cervical cancer in N.E. Scotland. T1anori 62, 287-95.
Cervical Cytology: Yorkshire Screening Service
321
13. Andrews, F. J., Linehan. J. J. & Melcher, D. H. (1978). Cervical cancer in younger women. Lancet ii, 776-8. 14. Yule, R. (1978). Mortality from carcinoma of the cervix. Lances i, 1051-2. 15. Cotton, R. (1980). Why D.H.S.S. screening policy puts young women unnecessarily at risk. World Medicine 15, 21-6. 16. McGregor, J. E., Fraser, M. E. & Mann, E. M. F. 0971). Improved prognosis ofcervical cancer due to comprehensive screening. Lancet i, 74-6. 17. Wakefield, J. & Baric, L. (1965). Public and professional attitudes to a screening programme for the prevention of cancer of lhe uterine cervix: a preliminary study. British Journal o f Preventive and Social Medicine 19, 151-8. 18, Leck. I., Sibary, K. & Wakefield, J. (i 978). Incidence ofcervicai cancer by marital status. Journal of Epidemiology and Community Health 32, 108-10. 19. The Walton Report (1976). Cervical cancer screening programs. 1. Epidemiology and natural history of carcinoma of the cervix. Canadian Medical Association Journal 114, 1003-12. 20. Beral, V. (1974). Cancer of the cervix: A sexually transmitted infection'?. Lancet L 1037-40.