The use of CA-125 in the diagnosis and management of endometriosis

Vol. 46, No.5, November 1986 Printed in U.SA.

FERTILITY AND STERILITY Copyright" 1986 The American Fertility Society

The use of CA-125 in the diagnosis and management of endometriosis

Donald E. Pittaway, M.D., Ph.D.* Jamil A. Fayez, M.D. Department of Obstetrics and Gynecology, Section of Reproductive Endocrinology, Bowman Gray School of Medicine, Winston-Salem, North Carolina

CA-125, a cell-surface antigen, was measured by a radioimmunoassay in the serum of 414 women to determine its potential usefulness in the diagnosis and management of endometriosis. In women with minimal, mild, moderate, and severe endometriosis, the mean levels (± standard deviation) were 13.6 ± 6.8,22.8 ± 15.5,27 ± 17, and 50 ± 28 Ulml, respectively, and were significantly higher than mean levels (7.8 ± 4.1) in 46 women with a normallaparoscopic examination. Higher mean CA-125 values also were observed in acute pelvic inflammatory disease, unexplained fertility, and pregnancy and during menstruation. The mean CA-125 value in women with treated endometriosis and a negative second-look laparoscopy was significantly lower than in women with untreated endometriosis. With the use of the 95% upper limit of 16 Ulml, the test had a sensitivity of 53% and specificity of 93%. The frequencies of elevated levels in minimal, mild, moderate, and severe endometriosis were 27%, 68%, 73%, and 100%, respectively. Changes in the CA-125 levels correlated with the clinical course of endometriosis in 37 of 44 (84%) women (P < 0.001). The determination of CA -125 levels may assist in the evaluation and treatment of women with endometriosis. Fertil Steril 46:790, 1986

CA-125 is a membrane antigen that is elevated in the serum of approximately 82% of patients with epithelial ovarian carcinomas, 1 in the serum of patients with advanced carcinomas of the endocervix, endometrium, and fallopian tube,2 in fetal Mullerian duct derivatives and serosal epithelial,2 and in adult Mullerian duct structures. 3 Although elevations of CA-125 levels 65 Ulml are rare in nonpregnant women without cancer,4 mild elevations of CA-125 levels have been observed in some women with endometriosis. 5 - 7 Received April 11, 1986; revised and accepted June 23, 1986. *Reprint requests: Donald E. Pittaway, M.D., Ph.D., Department of Obstetrics and Gynecology, Bowman Gray School of Medicine, 300 South Hawthorne Road, Winston-Salem, North Carolina 27103. 790

Pittaway and Fayez CA-125 in endometriosis

We measured the levels ofCA-125 in the serum of 414 women with endometriosis and other benign gynecologic conditions to evaluate the potential use ofCA-125 determinations in the diagnosis and management of endometriosis. MATERIALS AND METHODS

Serum samples were obtained from 392 consecutive women before they had laparoscopy or laparotomy for evaluation and/or treatment of infertility. Forty-six women had a normal pelvis; of these, 33 had ovulatory factor and 13 had male factor as the only cause for infertility. This group served as the "normal" group. Chronic pelvic inflammatory disease (PID) and tubal disease were found in 55 and 59 women, respectively. Fifteen women (7 cautery and 8 noncautery) were being Fertility and Sterility

evaluated for possible reversal of a previous tubal ligation. Vterine factor, cervical factor, and unexplained infertility were noted in 11, 4, and 17 women, respectively. Endometriosis was discovered in 130 women, and 26 women who had been treated for endometriosis were found not to have endometriosis at second-look laparotomy. In 29 women, the preoperative blood sample was drawn during menstruation; a separate group was established because of higher values observed at this time in the cycle. 6 During the study, 15 women with an early pregnancy (26 to 32 days after the last menses) and 7 women with acute PID were included because of suspected elevations of CA-125 in these conditions. All other nonpregnant women had samples drawn during the late follicular or the late luteal phase. Additional samples were obtained 4 to 12 weeks after treatment of endometriosis (36 women) when possible and in 8 women awaiting treatment after laparoscopic diagnosis. Treatment of endometriosis included operative laparoscopy or laparotomy with or without 2 to 3 months of postoperative danazol (600 to 800 mg/day). Evaluation of the status of the endometriosis at the completion of therapy was based on objective findings of the surgical result, a second-look laparoscopy, when performed, physical examination (nodularity and! or tenderness), and the patient's impressions of pain, if symptomatic. The endometriosis was categorized after therapy as no evidence of disease or evidence of disease. CA-125 was measured in serum samples with the use of a solid-phase radioimmunoassay, according to the supplier's instructions (Abbott Laboratories, North Chicago, IL). The standard curve was modified to include five reference standards between 2 and 45 Vimi. Between 2 and 45 Vlml, the intraassay and interassay coefficients of variation were 11% and 18%, respectively. A serum ~-human chorionic gonadotropin determination (Clinetics Corporation, Tustin, CA) was performed on each sample to exclude an occult pregnancy. The CA-125 assays were performed, and the findings were not known at laparoscopy and laparotomy. The staging ofthe severity ofthe endometriosis was according to the revised American Fertility Society classification. 8 Estimates ofthe amount of endometriosis in millimeters were made by adding the diameters of all visible implants in women without endometriomata retrospectively from operative summaries and diagrams. 8 A 40% reVol. 46, No.5, November 1986

duction or increase in the CA-125 levels, which is approximately two times the inter assay coefficient of variation, was considered significant in those patients sampled after no treatment, treatment, and suspected recurrence or persistence of endometriosis. Differences in the mean value were evaluated with the use of an unpaired t-test. The true-positive rate was defined as the percentage of women with endometriosis who had CA-125 levels about the upper confidence limit. The false-positive rate was defined as the percentage of women without endometriosis (not including pregnancy, menstruation, and acute PID) with CA-125 levels above the upper confidence limits. Correlation of the changes in CA-125 values with the clinical course were analyzed with the use of the Kappa test. 9

RESULTS The mean CA-125 levels (± standard deviation) for women without endometriosis and with endometriosis are shown in Table 1. Among 46 women without endometriosis and a normal lapTable 1. Serum CA-125 Levels in Women With and Without Endometriosis Group

No.

CA-125

(mean

±

SD)

Ulml

N onendometriosis Normal pelvis Ovulatory factor Male factor Chronic PID Tubal factor Tubal disease Tubal ligation Cautery Noncautery Uterine factor Cervical factor Unexplained infertility Other Menstruation Pregnancy Acute PID Endometriosis Minimal Mild Moderate Severe Posttreatment (NED)e

46 33 13

7.8 ± 4.1 8.0 ± 4.3 7.4 ± 3.6

55

10.7 ± 5.9a

59

8.9 ± 3.8

7 8 11 4 17

11.7 7.8 11.0 8.6 15.4

± ± ± ± ±

29 15 7

31.4 ± 13.4c 25.8 ± 19.8c 34.0 ± 21.7 c

55 37 30 8 26

13.6 22.8 27.8 49.6 6.5

± ± ± ± ±

6.2b 3.1 5.0 b 3.1 5.8 C

6.8 c 15.5c 17.3 c 28.0c 3.2d

aSignificantly different from normal pelvis, P < 0.01. bSignificantly different from normal pelvis, P < 0.02. CSignificantly different from normal pelvis, P < 0.001. dSignificantly different from minimal endometriosis, P < 0.001. eNo evidence of disease.

Pittaway and Fayez CA-125 in endometriosis

791

Table 2. The True-Positive Rate (TPR) and False-Positive Rate (FPR) of Detecting Endometriosis Using Serum CA-125 Values Upper confidence

CA-125

limit %

Ulml

99 95 90 85 80 75 50

20.1 16.0 14.5 13.7 13.2 12.5 11.1

TPR ± SD (n = 130)

FPR ± SD (n = 233) %

%

39 53 58 60 62 66 78

± ± ± ± ± ± ±

4 4 4 4 4 4 4

2 7 12 18 21 27 32

± ± ± ± ± ± ±

1 2 3 3 3 3 4

aroscopic examination, the mean CA-125 value was 7.8 ± 4.1 VlmI. Infertile women with unexplained infertility, chronic PID, uterine factor, and tubal ligation by cautery had higher mean levels. W~men with an early pregnancy or acute PID or who were menstruating had significantly higher mean CA-125 values. The mean CA-125 values in women with minimal to severe endometriosis increased with the severity of disease and were significantly higher than those in women with a normal pelvis. In 26 women with treated endometriosis and no apparent disease at secondlook laparoscopy, the mean CA-125 level was 6.5 ± 3.2 Ulml, which was significantly lower than in minimal endometriosis. In Table 2 are shown the upper confidence limits of the CA-125 values determined from 46 women with normal laparoscopic examination and the corresponding true-positive and false-positive rates. A CA-125 value in our assay of ~ 16.0 Vlml (which corresponds to the 95% upper limit) 1

was considered abnormal and resulted in a truepositive rate (sensitivity) of 53% and a false-positive rate of7% (specificity = 93%). In Figure 1 are shown the CA-125 levels for women with and without endometriosis. The numbers in the boxes indicate the number of women with CA-125 levels < 16.0 UlmI. Overall, 70 of 130 women (54%) with endometriosis had elevated levels. The frequencies of elevated levels in women with minimal, mild, moderate, and severe endometriosis were 27%, 68%, 73%, and 100%, respectively. Excluding women with an early pregnancy (73%), menstruation (93%), or acute PID (100%), 19 of 206 infertile women (9%) without endometriosis had elevated CA-125 values. The proportions of elevated levels in women with chronic PID, unexplained infertility, and tubal ligations by electrocoagulation were 13%, 41%, and 28%, respectively. Because the classification of endometriosis places a relatively high weight on the presence of adhesions, deep lesions, and endometriomata,8 we correlated the total amount of visible endometriosis, in millimeters, with the corresponding CA-125 value (Fig. 2). A positive correlation (r = 0.64) was observed in 46 women with only peritoneal disease, although a high degree of variability of the CA-125 levels was noted at each total diameter. In 44 women with endometriosis, at least two (range, two to five) CA-125 determinations were obtained (Fig. 3). In 8 women who received no therapy between laparoscopy and laparotomy, the CA-125 values remained unchanged in 6 and in-

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Pittaway and Fayez CA-125 in endometriosis

Figure 1 Serum CA-125 levels in women with and without endometriosis. The number of patients with values < 16 U/ml is indicated within the boxes.

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Figure 2 Correlation of the amount of endometriosis in millimeters with serum CA-125 levels.

creased in 2 women, 1 of whom developed an endometrioma that was not evident at laparoscopy. Of the 20 women with no evidence of disease, 17 had a significant decrease (~ 40%) in CA-125 levels, whereas 12 of 16 women with evidence of endometriosis had persistently elevated or rising levels of CA-125. Overall, the CA-125 values correlated with the clinical course in 37 of 44 (84%) women with endometriosis (P < 0.001). In Figure 4 are shown prediagnosis and subsequent CA-125 values for five women with endometriosis. The CA-125 levels in all five women decreased after combined surgical and medical treatment. One patient (C.B.) had recurrence of pain and tenderness on examination approximately 3 months after discontinuing danazol treatment, with an increase of the CA-125 levels to the pretreatment baseline. One pregnancy occurred (M.F.) approximately 2 months after danazol treatment ended. Patient K.W. illustrates the effect of menstruation (day 7) on CA-125 levels (increase from 33 to 228 VlmI) in women with endometriosis. In E.P., with severe pelvic pain and endometriosis, CA-125 levels decreased after treatment, and the patient has been free of symptoms for 3 months after danazol treatment ended. An endometrioma developed in K.B. during the 3-month interval between diagnosis and conservative surgery, with a corresponding rise in the CA-125 level and decrease with therapy. DISCUSSION

In addition to providing a useful marker of epithelial ovarian cancers, this study demonstrates a Vol. 46, No.5, November 1986

potential use of CA-125 determinations in the diagnosis and management of endometriosis. CA-125 concentrations> 35 Vlml and> 65 Vlml have been empirically selected to identify women likely to have epithelial ovarian cancer,! but it is evident from the CA-125 levels in women with a normal pelvis that these levels far exceed the upper limits of normal nonmenstruating women. In addition, these levels were selected from a population of women who did not have an evaluation of their pelvis, who were not excluded if values were obtained during menses, and whose samples were not assayed in a RIA modified to improve the standard care in the 2- to 45-Vlml range. The mean CA-125 level in the cancer study for women was 9.9 Vlml, with a 95% upper limit of 25.9 Vlml. 1 With levels of CA-125 of ~ 16.0 Vlml, endometriosis was detected in 53% of women (sensitivity), with a specificity of93% in the study population when the incidence of endometriosis was 39%. At levels> 20 Vlml in the study population, 96% specificity was observed in the nonpregnant, nonmenstruating woman without acute PID. Seven of 17 patients with unexplained infertility had elevated levels and may have occult endometriosis or other peritoneal irritants, as has been suggested by increased peritoneal fluid prostanoids. 10 Also, intratubal endometriosis has been described in some patients after tubal ligation l l and may be a possible explanation for the elevation in two women without apparent endometriosis who had had a tubal sterilization by electrocoagulation. We previously reported that 70 60

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Figure 3 Serum CA-125 levels in patients with no therapy, therapy with no evidence of endometriosis, and therapy with evidence of persistent or recurrent endometriosis. Pittaway and Faye~ CA-125 in endometriosis

793

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Figure 4 Serial measurement of CA-125 in five women with endometriosis.

higher CA-125 levels occur during menstruation in women 6 and nonhuman primates 12 with and without endometriosis. In this reproductive age group, ovarian and other malignancies are uncommon but would be another potential source of a false-positive result with respect to the presence of endometriosis. The levels of CA-125 correlated with the severity of endometriosis with both a clinical classification system8 and estimates of the total amount of endometriosis visible at surgery. In addition, significantly lower levels were obtained after treatment when no endometriosis was found at secondlook laparoscopy. However, many patients with lesions characteristic of endometriosis had nonelevated levels of CA-125. Whether this discrepancy is because of the insensitivity of the antigen marker or the possibility that lesions with the characteristic appearance of endometriosis are either inactive or not endometriosis remains to be determined. A statistically significant correlation was found between CA-125 levels and the clinical course of the endometriosis. Of the seven women whose values did not correlate, three had CA-125 levels

decrease < 40% from the pretreatment levels. Four women had a significant decrease in their CA-125 values with persistent endometriosis at second-look laparoscopy, although in each case the severity score8 had decreased. The development of a serum test for evaluating women for endometriosis would provide an important addition to gynecology. The findings of this study support the use of a modified CA-125 assay in the diagnosis and management of women with endometriosis. The determination ofCA-125 concentrations is not without drawbacks, because many women with minimal (73%), mild (32%), or moderate (27%) endometriosis have levels below our upper limit. Nonetheless, when CA-125 levels are elevated in an infertility population, the likelihood of endometriosis is very high (93% to 96%, depending on whether the level is > 16 Vlml or > 20 UlmI). At present, laparoscopy offers the most specific and sensitive technique for evaluating and monitoring endometriosis. However, with a high proportion of women with infertility, pelvic pain, and dysmenorrhea having endometriosis, much of which is occult clinically, and with a significant rate of persistence and recurrence of endometriosis after therapy,13, 14 a serum marker such as CA-125 may offer much-needed assistance to the clinician. REFERENCES 1. Bast RC Jr, Klug TL, St. John E, Jenison E, Niloff JM,

Lazarus H, Berkowitz RS, Leavitt T, Griffiths CT, Parker L, Zurawski VR, Knapp RC: A radioimmunoassay using a monoclonal antibody to monitor the course of epithelial ovarian cancer. N Engl J Med 309:883, 1983 2. Niloff JM, Klug TL, Schaetzl E, Zurawski VR, Knapp RC, Bast RC Jr: Elevation of serum CA-125 in carcinomas of the fallopian tube, endometrium, and endocervix. Am J Obstet GynecoI148:1057, 1984 3. Kabawat SE, Bast RC Jr, Bhan A, Welch RC, Knapp RC, Colvin RB: Tissue distribution of a coelomic epitheliumrelated antigen recognized by the monoclonal antibody OC 125. Lab Invest 48:42A, 1983 4. Niloff JM, Knapp RC, Schaetzl E, Reynolds C, Bast RC Jr: CA-125 antigen levels in obstetrics and gynecologic patients. Obstet Gynecol 64:703, 1984 5. Barbieri RL, Niloff JM, Bast RC, Schaetzl E, Kistner RW, Knapp RC: Elevated serum concentrations of CA-125 in patients with advanced endometriosis. Fertil Steril 45:630, 1986 6. Pittaway DE, Fayez JA: Serum CA-125 antigen levels increase during menses. Am J Obstet Gynecol. In press 7. Einhorn N, Bast RC Jr, Knapp RC, Tjernberg B, Zurawski VR: Preoperative evaluation of serum CA-125 levels in patients with primary epithelial ovarian cancer. Obstet Gynecol 67:414, 1986

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Pittaway and Fayez CA-125 in endometriosis

8. The American Fertility Society: Revised American Fertility Society Classification of Endometriosis: 1985. Fertil Steril 43:351, 1985 9. Cohen J: A coefficient of agreement for nominal scales. Educ Psychol Mens 20:37, 1960 10. Drake TS, O'Brien WF, Ramwell PW: Peritoneal fluid prostanoids in unexplained infertility. Am J Obstet Gynecol 147:63, 1983 11. Rock JA, Parmley TH, King TM, Laufe LE, Su BC: Endometriosis and the development of tuboperitoneal fistulas after tubal ligation. Fertil Steril 35:16, 1981

Vol. 46, No.5, November 1986

12. Pittaway DE, Klimek M, Koritnik DR: CA-125 antigen in rhesus monkeys with spontaneous endometriosis. Fertil Steril 46:968, 1986 13. Barbieri RL, Evans S, Kistner RW: Danazol in the treatment of endometriosis: analysis of 100 cases with a 4-year follow-up. Fertil Steril 37:737, 1982 14. Buttram VC Jr, Reiter RC, Ward S: Treatment of endometriosis with danazol: report of a 6-year prospective study. Fertil Steril 43:353, 1985

Pittaway and Fayez CA-125 in endometriosis

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