- Email: [email protected]
Malignant anal tumours in the Chinese population in Hong Kong
SurgkalOncology 1996; 5: 65-68
Malignant anal tumours in the Chinese population in Hong Kong C. K. LEOW, C. C. CHUNG, W. Y. LAU AND A. K. C. LI Department of Surgery, The Chinese University of Hong Kong, Prince of Wales Hospital, Shetin, New Territories, Hong Kong
Malignant anal tumours are rare cancers but are particularly common in Switzerland, Poland and Brazil. Very little is known about this condition in the Chinese population. A retrospective study, covering an 11-year period, was performed. A total of 18 patients were treated at the Prince of Wales Hospital, Hong Kong. There were eight squamous cell carcinomas, seven adenocarcinomas and one each of adenosquamous carcinoma, malignant melanoma and leiomyosarcoma. Bleeding per rectum, with or without perianal pain, was the main presenting symptom. Abdominoperineal resection was the treatment modality used in most cases. Adenocarcinomas, seen mainly in males, accounted for about 39% of cases, a figure much higher than that published elsewhere. Another 44% of patients, predominantly females, had squamous cell carcinoma. None had a positive past history of sexually transmitted disease. The local prevalence of HPV infection is much lower than in the Western world, and the role of HPV in the oncogenesis of anal tumours in the Chinese population awaits elucidation. Surgical Oncology
1996; 5: 65-68. Keywords: Chinese, human papillomavirus, malignant anal tumours.
the New Territories of Hong Kong. All patient records with a diagnosis of anal tumour were reviewed retrospectively. Patient information including presenting symptoms, relevant past history, and operative and non-operative treatment records were noted. In particular, both the macroscopic and microscopic descriptions of the lesion in the histopathological report were reviewed. The tumour site was then classified as recommended by the World Health Organization (WHO) [6].
INTRODUCTION Anal tumours account for 1-6% of all anorectal tumours [1, 2]. The majority of tumours of the anal region are squamous cell carcinomas (up to 80%) [3]. Primary anal adenocarcinoma is rare. Over a 40-year period, Merlini & Eckert reported nine adenocarcinomas among 106 anal tumours [4]. Although anal cancers do occur throughout the world, they are particularly common in Switzerland, Poland and Brazil [5]. We reviewed our experience in Chinese patients with anal tumours treated at the Prince of Wales Hospital, The Chinese University of Hong Kong from 1984 to January 1995.
RESULTS A total of 18 patients (11 females and 7 males) were treated. There were three squamous cell carcinomas (16.7%), five basaloid squamous carcinomas (27.8%), seven adenocarcinomas (38.9%) and one each of adenosquamous carcinoma, malignant melanoma and leiomyosarcoma. Squamous cell carcinomas were more common in females (7/8), while adenocarcinomas were predominant in males (5/7). All the adenocarcinomas and 75% (6/8) of the squamous carcinomas
PATIENTS AND METHODS The Prince of Wales Hospital, serving a population of 1.2 million, is the principal teaching hospital in Correspondence: Prof. A. K. C. Li, Department of Surgery, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong. © 1996 Blackwell Science
Ltd
65
C. K. Leow et al.
66
were found within the anal canal. Only two of the squamous carcinomas were located at the anal verge (Table 1). The mean age of the two groups was not significantly different (Student's r-test, P>0.05). Bleeding, with or without perianal pain, was the presenting symptom in all but one patient. This patient (no. 5). who presented with intestinal obstruction, had noticed a palpable lump at the anus 1 year prior to presentation. Abdominoperineal resection was performed in 11 patients, two received radiotherapy, one (no. 5) was palliated with a colostomy and one (no. 7) had supportive treatment only due to advanced age and poor general condition. One interesting characteristic among these patients was the preponderance of locally advanced disease at presentation. The majority of these tumours have already infiltrated into or through the sphincteric muscle. Only four of the 15 patients, with either squamous carcinoma or adenocarcinoma, are still alive after more than 4 years following the initial treatment. One patient (no. 12) developed lymph node metastases in the groin 9 months after the initial treatment. This responded to radiotherapy and she is still alive.
DISCUSSION Anal carcinoma behaves as two distinct clinical entities: tumour of the anal canal and tumour of the anal margin. The exact extent of the anal canal described in the literature is confusing. About 70% of all anal tumours occur in the anal canal if the dentate line is taken as the distal limit of the canal [7-12). If the extent of the canal, as recommended by WHO [6). is from the anorectal ring to the anal verge (the junction of the modified squamous epithelium of the pecten with the perianal skin) the figure becomes 85% [13-20). Moreover, there is also confusion over the lateral extent of the anal margin. Beahrs & Wilson suggested that this is within 5 cm of the anal verge [15). Seventy-five per cent of the squamous carcinoma in our series occur in the canal, as defined by WHO [6). This is comparable to results reported by others [13-16, 19, 20). Accurate localization of the lesion within the anus dictates treatment options and prognosis. Schraut et al. advocated local excision for superficially invasive tumours that are less than 2 cm in diameter [18). Despite such favourable circumstances, local recurrence can still occur. Frost and co-workers reported the presence
Table 1. Patients with squamous cell carcinoma (SQUAME) and adenocarcinoma (ADENa) of the anus
Patient no.
Sex
Age (years)
Symptoms (months)
Site
Invasion
Histology
Primary (adjuvant) treatment
Outcome (months)
Recurrence
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
M M M M M
74 67 42 76 64 84 65 65 57 53 73 66 63 45
AC AC AC AV * AC AV AC AC AC AC AV AV AC AC
m m m In In m * In m m m t m In In
ADENa ADENa ADENa ADENa ADENa ADENa ADENa SQUAME SQUAME SQUAME SQUAME SQUAME SQUAME SQUAME SQUAME
APR APR APR (Chemo) APR * APR (RT) * APR (RT) RT (Salvage APR) APR APR RT APR (RT) APR APR (Chemo)
Alive (55) Died (7) Alive (49) Died (7) Defaulted Died (7) Alive (4) Died (22) Died (42) Defaulted Alive (142) Alive (48) Died (56) Defaulted Died (30)
No Yes No Yes
F F F F F F F F F
B (1) B+P (3) B (6) B+P (6) * B+P (6) B+P (2) B (2) B (2) B+P (3) B+P B (24) B (12) B (3) B+P (2)
M
72
*Refer to text. tUn known, incisional biopsy only. B = bleeding per rectum; P = perianal pain; AC node; APR = abdominoperineal resection.
= anal
canal; AV
= anal
verge; m
= muscle;
No Yes Yes No Yes Yes Yes Yes
In = locoregional lymph
©1996 Blackwell Science Ltd, Surgical Oncology, 5: 65-68
Malignant anal tumours in Chinese
of nodal metastases in 8% of such cases [21]. Abdominoperineal resection, a therapeutic modality against which all other forms of treatment must be compared [12], was the treatment of choice. The published 5-year survival rates range from 38 to 71%, reflecting differences in patient selection [12]. The obvious drawback of surgery is the loss of anal sphincters and permanent colostomy formation. With the advent of radiotherapy, megavoltage external beam radiation provided a 5-year survival rate of 60-70% [22]. The pioneering work of Nigro et al. in combining chemotherapy with radiotherapy for treating anal canal tumour [23] is now advocated by many. The 5-year survival rate with this combined treatment is 70% [3]. The question of whether combined therapy is superior to radiotherapy alone will hopefully be answered by the UKCCCR anal cancer trial [24]. The majority of our cases were treated by abdominoperineal resection. One of two patients treated with radiotherapy had to have salvage abdominoperineal resection due to progression of the disease. Our much higher rate of abdominoperineal resection reflects the presence of locally advanced disease involving underlying muscle and/or locoregional lymph nodes. Thirty per cent of tumours confined to the submucosa have nodal metastases, but once there is underlying muscle involvement, the incidence rises above 60% [21]. Approximately 40% of our malignant anal tumours were adenocarcinomas. This is much higher than in previous reports [3, 4]. One possible explanation is that a proportion of these tumours were not primary anal adenocarcinoma but resulted from the down-growth of a primary rectal tumour. However, a review of all our seven cases suggested that this is unlikely. In six of the seven cases, the ulcerative lesion was found to be situated in the anal canal. The seventh case, presenting with intestinal obstruction, could possibly be a case of low rectal carcinoma which extended downwards. The clear-cut history of a palpable lump at the anus without any other symptoms, 1 year prior to presentation, would be in favour of a primary anal lesion. Adenocarcinoma of the anus should be considered as analogous to rectal adenocarcinoma, and the treatment is abdominoperineal resection. Anal canal carcinoma is more common in women (M : F 2: 3) while anal margin tumours show © 1996 Blackwell Science Ltd, Surgical Oncology, 5: 65-68
67
a male preponderance (M : F 4: 1) [13, 15, 25, 26]. In our series, seven of eight patients were females. None of these patients had a past history of anogenital warts, a known risk factor for anal squamous cell carcinoma [27]. The association of human papillomavirus (HPV)-especially type 16-in anal squamous cell cancers is well recognized [5, 28]. The prevalence of HPV-associated anal squamous carcinoma is not known in the Chinese population. Only 7% of local women with a negative cervical cytological smear tested positive for HPV DNA (Dr Y. F. Wong, personal communication). This is much less than the 17.7% detected in a group of low-risk women in the USA [29]. Although the association of HPV as an aetiological agent in the development of anal carcinoma is strong, geographical differences in the prevalence of HPV infection imply that risk factors other than HPV may play an important role in the aetiology of anal squamous cell carcinoma in Hong Kong; a situation not dissimilar to that found with cervical cancer in China [30]. In conclusion, a single universally accepted definition on the extent of the anal canal should be adopted, not only to facilitate the choice of treatment but also to allow a comparison of treatment outcome between centres on comparable lesions. Malignant anal tumours are rare in the Chinese population. The majority of the tumours we found were squamous cell carcinomas and adenocarcinomas, in almost equal proportions. The incidence of anal adenocarcinoma reported here is much higher than elsewhere, afflicting mainly men. Squamous cell carcinomas were predominantly found in women, none of whom had a past history of sexually transmitted disease. The role of human papillomavirus in anal carcinoma in this population is not known. Epidemiological studies of the prevalence of genital HPV infections are required; this would then provide information on the possible oncogenic HPV types associated with anal carcinomas in the Chinese population in Hong Kong.
REFERENCES 1. Morson BC. The pathology and results of treatment of cancer of the anal region. Proc R Soc Med 1959; 53: 416-9. 2. Richards JC, Bearhs OH, Woolner LB. Squamous cell carcinoma of the anus, anal canal and rectum in 109
68
C. K. Leow et al.
patients. Surg GynecolObstet 1962; 114: 475-9. 3. Deans GT, McAleer JJA, Spence RAJ. Malignant anal tumours. Br J Surg 1994; 81: 500-8. 4. Merlini M, Eckert P. Malignant tumours of the anus. Am J Surg 1985; 150: 370-2. 5. Scholefield JH, Kerr IB, Shepherd NA, Miller KJ, Bloomfield R, Northover JMA. Human papillomavirus type 16 DNA in anal cancers from six different countries. Gut 1991; 32: 674-6. 6. Morson BC, Sobin LH. Histological typing of intestinal tumours. In: International Histological Classification of Tumours, No. 15. Geneva: World Health Organization, 1976: 67-9. 7. Morson BC. The pathology and results of treatment of squamous cell carcinoma of the anal canal and anal margin. J R Soc Med 1960; 61: 623-4. 8. Hardcastle JD, Bussey HJR. Results of surgical treatment of squamous cell carcinoma of the anal canal and anal margin seen at St. Marks Hospital 1928-66. J R Soc Med 1968; 61: 629-30. 9. Hardy KJ, Hughes ESR, Cuthbertson AM. Squamous cell carcinoma of the anal canal and anal margin. Aust NZ J Surg 1969; 38: 301-5. 10. AI-Jurf AS, Turnbull RB, Fazio VW. Local treatment of squamous cell carcinoma of the anus. Surg Gynecol Obstet 1979; 148: 574-8. 11. O'Brien PH, Jenrette JM, Wallace KM, Metcalf JS. Epidermoid carcinoma of the anus. Surg Gynecol Obstet 1982; 155: 745-51. 12. Greenall MJ, Quan SHQ, Stearns MW, Urmacher C, DeCosse JJ. Epidermoid cancer of the anal margin. Pathologic features, treatment and clinical results. Am J Surg 1985; 149: 95-101. 13. Klotz RG, Pamukoglu T, Souillard DH. Transitional cloagenic carcinoma of the anal canal. Clinicopathological study of 373 cases. Cancer 1967; 20: 1727-45. 14. Kuehn PG, Eisenberg H, Reed JF. Epidermoid carcinoma of the perianal skin and anal canal. Cancer 1968; 22: 932-8. 15. Beahrs OH, Wilson SM. Carcinoma of the anus. Ann Surg 1976; 184: 422-8. 16. Singh R, Nime F, Mittelman A. Malignant epithelial tumours of the anal canal. Cancer 1981; 48: 411-5.
17. Papillon J. Rectal and Anal Cancers. Berlin: SpringerVerlag, 1982. 18. Schraut WH, Wang C, Dawson PJ, Block GE. Depth of invasion, location and size of cancer of the anus dictate operation treatment. Cancer 1983; 51: 1291-6. 19. Boman BM, Moertel CG, O'Connell MJ, Scott M, Weiland LH, Beart RW. Carcinoma of the anal canal. A clinical and pathologic study of 188 cases. Cancer 1984; 54: 114-25. 20. Clark J, Petrelli N, Herrera LM, Heimann A. Epidermoid carcinoma of the anal canal. Cancer 1986; 57: 400-6. 21. Frost DB, Richards PC, Montague ED, Giacco GG, Martin RG. Epidermoid cancer of the anorectum. Cancer 1984; 53: 1285-93. 22. Greenall MJ, Quan SHQ, DeCosse JJ. Epidermoid cancer of the anus. Br J Surg 1985; 72(Suppl.): S97-S103. 23. Nigro ND, Vaitkevicius VK, Considine B. Combined therapy for cancer of the anal canal: a preliminary report. Dis Colon Rectum 1974; 17: 354-6. 24. United Kingdom Co-ordinating Committee for Cancer Research (UKCCCRj Anal Cancer Trial Protocol. London: CRC Clinical Trials Centre, 1992. 25. Stearns MW, Ouan SH. Epidermoid carcinoma of the anorectum. Surg Gynecol Obstet 1970; 131: 953-7. 26. Pang LSC, Morson BC. Basaloid carcinoma of the anal canal. J Clin Patho/1967; 20: 128-35. 27. Daling JR, Weiss NS, Hislop TG, et al. Sexual practices, sexually transmitted diseases and the incidence of anal cancer. N Engl J Med 1987; 317: 973-7. 28. Palmer JG, Shepherd NA, Jass JR, Crawford LV, Northover JMA. Human papillomavirus type 16 DNA in anal squamous cell carcinoma. Lancet 1987; ii: 42. 29. Bauer HM, Hildesheim A, Schiffman MH, et al. Determinants of genital human papillomavirus infection in low-risk women in Portland, Oregon. Sex Transm Dis 1993; 20: 274-8. 30. Pao CC, Kao SM, Tang GC, Kun Lee JS, Ruan S. Human papillomavirus and cervical carcinoma in China and Taiwan. Lancet 1993; 342: 937.
© 1996 Blackwell Science Ltd, Surgical Oncology, 5: 65-68
Malignant anal tumours in the Chinese population in Hong Kong C. K. LEOW, C. C. CHUNG, W. Y. LAU AND A. K. C. LI Department of Surgery, The Chinese University of Hong Kong, Prince of Wales Hospital, Shetin, New Territories, Hong Kong
Malignant anal tumours are rare cancers but are particularly common in Switzerland, Poland and Brazil. Very little is known about this condition in the Chinese population. A retrospective study, covering an 11-year period, was performed. A total of 18 patients were treated at the Prince of Wales Hospital, Hong Kong. There were eight squamous cell carcinomas, seven adenocarcinomas and one each of adenosquamous carcinoma, malignant melanoma and leiomyosarcoma. Bleeding per rectum, with or without perianal pain, was the main presenting symptom. Abdominoperineal resection was the treatment modality used in most cases. Adenocarcinomas, seen mainly in males, accounted for about 39% of cases, a figure much higher than that published elsewhere. Another 44% of patients, predominantly females, had squamous cell carcinoma. None had a positive past history of sexually transmitted disease. The local prevalence of HPV infection is much lower than in the Western world, and the role of HPV in the oncogenesis of anal tumours in the Chinese population awaits elucidation. Surgical Oncology
1996; 5: 65-68. Keywords: Chinese, human papillomavirus, malignant anal tumours.
the New Territories of Hong Kong. All patient records with a diagnosis of anal tumour were reviewed retrospectively. Patient information including presenting symptoms, relevant past history, and operative and non-operative treatment records were noted. In particular, both the macroscopic and microscopic descriptions of the lesion in the histopathological report were reviewed. The tumour site was then classified as recommended by the World Health Organization (WHO) [6].
INTRODUCTION Anal tumours account for 1-6% of all anorectal tumours [1, 2]. The majority of tumours of the anal region are squamous cell carcinomas (up to 80%) [3]. Primary anal adenocarcinoma is rare. Over a 40-year period, Merlini & Eckert reported nine adenocarcinomas among 106 anal tumours [4]. Although anal cancers do occur throughout the world, they are particularly common in Switzerland, Poland and Brazil [5]. We reviewed our experience in Chinese patients with anal tumours treated at the Prince of Wales Hospital, The Chinese University of Hong Kong from 1984 to January 1995.
RESULTS A total of 18 patients (11 females and 7 males) were treated. There were three squamous cell carcinomas (16.7%), five basaloid squamous carcinomas (27.8%), seven adenocarcinomas (38.9%) and one each of adenosquamous carcinoma, malignant melanoma and leiomyosarcoma. Squamous cell carcinomas were more common in females (7/8), while adenocarcinomas were predominant in males (5/7). All the adenocarcinomas and 75% (6/8) of the squamous carcinomas
PATIENTS AND METHODS The Prince of Wales Hospital, serving a population of 1.2 million, is the principal teaching hospital in Correspondence: Prof. A. K. C. Li, Department of Surgery, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong. © 1996 Blackwell Science
Ltd
65
C. K. Leow et al.
66
were found within the anal canal. Only two of the squamous carcinomas were located at the anal verge (Table 1). The mean age of the two groups was not significantly different (Student's r-test, P>0.05). Bleeding, with or without perianal pain, was the presenting symptom in all but one patient. This patient (no. 5). who presented with intestinal obstruction, had noticed a palpable lump at the anus 1 year prior to presentation. Abdominoperineal resection was performed in 11 patients, two received radiotherapy, one (no. 5) was palliated with a colostomy and one (no. 7) had supportive treatment only due to advanced age and poor general condition. One interesting characteristic among these patients was the preponderance of locally advanced disease at presentation. The majority of these tumours have already infiltrated into or through the sphincteric muscle. Only four of the 15 patients, with either squamous carcinoma or adenocarcinoma, are still alive after more than 4 years following the initial treatment. One patient (no. 12) developed lymph node metastases in the groin 9 months after the initial treatment. This responded to radiotherapy and she is still alive.
DISCUSSION Anal carcinoma behaves as two distinct clinical entities: tumour of the anal canal and tumour of the anal margin. The exact extent of the anal canal described in the literature is confusing. About 70% of all anal tumours occur in the anal canal if the dentate line is taken as the distal limit of the canal [7-12). If the extent of the canal, as recommended by WHO [6). is from the anorectal ring to the anal verge (the junction of the modified squamous epithelium of the pecten with the perianal skin) the figure becomes 85% [13-20). Moreover, there is also confusion over the lateral extent of the anal margin. Beahrs & Wilson suggested that this is within 5 cm of the anal verge [15). Seventy-five per cent of the squamous carcinoma in our series occur in the canal, as defined by WHO [6). This is comparable to results reported by others [13-16, 19, 20). Accurate localization of the lesion within the anus dictates treatment options and prognosis. Schraut et al. advocated local excision for superficially invasive tumours that are less than 2 cm in diameter [18). Despite such favourable circumstances, local recurrence can still occur. Frost and co-workers reported the presence
Table 1. Patients with squamous cell carcinoma (SQUAME) and adenocarcinoma (ADENa) of the anus
Patient no.
Sex
Age (years)
Symptoms (months)
Site
Invasion
Histology
Primary (adjuvant) treatment
Outcome (months)
Recurrence
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
M M M M M
74 67 42 76 64 84 65 65 57 53 73 66 63 45
AC AC AC AV * AC AV AC AC AC AC AV AV AC AC
m m m In In m * In m m m t m In In
ADENa ADENa ADENa ADENa ADENa ADENa ADENa SQUAME SQUAME SQUAME SQUAME SQUAME SQUAME SQUAME SQUAME
APR APR APR (Chemo) APR * APR (RT) * APR (RT) RT (Salvage APR) APR APR RT APR (RT) APR APR (Chemo)
Alive (55) Died (7) Alive (49) Died (7) Defaulted Died (7) Alive (4) Died (22) Died (42) Defaulted Alive (142) Alive (48) Died (56) Defaulted Died (30)
No Yes No Yes
F F F F F F F F F
B (1) B+P (3) B (6) B+P (6) * B+P (6) B+P (2) B (2) B (2) B+P (3) B+P B (24) B (12) B (3) B+P (2)
M
72
*Refer to text. tUn known, incisional biopsy only. B = bleeding per rectum; P = perianal pain; AC node; APR = abdominoperineal resection.
= anal
canal; AV
= anal
verge; m
= muscle;
No Yes Yes No Yes Yes Yes Yes
In = locoregional lymph
©1996 Blackwell Science Ltd, Surgical Oncology, 5: 65-68
Malignant anal tumours in Chinese
of nodal metastases in 8% of such cases [21]. Abdominoperineal resection, a therapeutic modality against which all other forms of treatment must be compared [12], was the treatment of choice. The published 5-year survival rates range from 38 to 71%, reflecting differences in patient selection [12]. The obvious drawback of surgery is the loss of anal sphincters and permanent colostomy formation. With the advent of radiotherapy, megavoltage external beam radiation provided a 5-year survival rate of 60-70% [22]. The pioneering work of Nigro et al. in combining chemotherapy with radiotherapy for treating anal canal tumour [23] is now advocated by many. The 5-year survival rate with this combined treatment is 70% [3]. The question of whether combined therapy is superior to radiotherapy alone will hopefully be answered by the UKCCCR anal cancer trial [24]. The majority of our cases were treated by abdominoperineal resection. One of two patients treated with radiotherapy had to have salvage abdominoperineal resection due to progression of the disease. Our much higher rate of abdominoperineal resection reflects the presence of locally advanced disease involving underlying muscle and/or locoregional lymph nodes. Thirty per cent of tumours confined to the submucosa have nodal metastases, but once there is underlying muscle involvement, the incidence rises above 60% [21]. Approximately 40% of our malignant anal tumours were adenocarcinomas. This is much higher than in previous reports [3, 4]. One possible explanation is that a proportion of these tumours were not primary anal adenocarcinoma but resulted from the down-growth of a primary rectal tumour. However, a review of all our seven cases suggested that this is unlikely. In six of the seven cases, the ulcerative lesion was found to be situated in the anal canal. The seventh case, presenting with intestinal obstruction, could possibly be a case of low rectal carcinoma which extended downwards. The clear-cut history of a palpable lump at the anus without any other symptoms, 1 year prior to presentation, would be in favour of a primary anal lesion. Adenocarcinoma of the anus should be considered as analogous to rectal adenocarcinoma, and the treatment is abdominoperineal resection. Anal canal carcinoma is more common in women (M : F 2: 3) while anal margin tumours show © 1996 Blackwell Science Ltd, Surgical Oncology, 5: 65-68
67
a male preponderance (M : F 4: 1) [13, 15, 25, 26]. In our series, seven of eight patients were females. None of these patients had a past history of anogenital warts, a known risk factor for anal squamous cell carcinoma [27]. The association of human papillomavirus (HPV)-especially type 16-in anal squamous cell cancers is well recognized [5, 28]. The prevalence of HPV-associated anal squamous carcinoma is not known in the Chinese population. Only 7% of local women with a negative cervical cytological smear tested positive for HPV DNA (Dr Y. F. Wong, personal communication). This is much less than the 17.7% detected in a group of low-risk women in the USA [29]. Although the association of HPV as an aetiological agent in the development of anal carcinoma is strong, geographical differences in the prevalence of HPV infection imply that risk factors other than HPV may play an important role in the aetiology of anal squamous cell carcinoma in Hong Kong; a situation not dissimilar to that found with cervical cancer in China [30]. In conclusion, a single universally accepted definition on the extent of the anal canal should be adopted, not only to facilitate the choice of treatment but also to allow a comparison of treatment outcome between centres on comparable lesions. Malignant anal tumours are rare in the Chinese population. The majority of the tumours we found were squamous cell carcinomas and adenocarcinomas, in almost equal proportions. The incidence of anal adenocarcinoma reported here is much higher than elsewhere, afflicting mainly men. Squamous cell carcinomas were predominantly found in women, none of whom had a past history of sexually transmitted disease. The role of human papillomavirus in anal carcinoma in this population is not known. Epidemiological studies of the prevalence of genital HPV infections are required; this would then provide information on the possible oncogenic HPV types associated with anal carcinomas in the Chinese population in Hong Kong.
REFERENCES 1. Morson BC. The pathology and results of treatment of cancer of the anal region. Proc R Soc Med 1959; 53: 416-9. 2. Richards JC, Bearhs OH, Woolner LB. Squamous cell carcinoma of the anus, anal canal and rectum in 109
68
C. K. Leow et al.
patients. Surg GynecolObstet 1962; 114: 475-9. 3. Deans GT, McAleer JJA, Spence RAJ. Malignant anal tumours. Br J Surg 1994; 81: 500-8. 4. Merlini M, Eckert P. Malignant tumours of the anus. Am J Surg 1985; 150: 370-2. 5. Scholefield JH, Kerr IB, Shepherd NA, Miller KJ, Bloomfield R, Northover JMA. Human papillomavirus type 16 DNA in anal cancers from six different countries. Gut 1991; 32: 674-6. 6. Morson BC, Sobin LH. Histological typing of intestinal tumours. In: International Histological Classification of Tumours, No. 15. Geneva: World Health Organization, 1976: 67-9. 7. Morson BC. The pathology and results of treatment of squamous cell carcinoma of the anal canal and anal margin. J R Soc Med 1960; 61: 623-4. 8. Hardcastle JD, Bussey HJR. Results of surgical treatment of squamous cell carcinoma of the anal canal and anal margin seen at St. Marks Hospital 1928-66. J R Soc Med 1968; 61: 629-30. 9. Hardy KJ, Hughes ESR, Cuthbertson AM. Squamous cell carcinoma of the anal canal and anal margin. Aust NZ J Surg 1969; 38: 301-5. 10. AI-Jurf AS, Turnbull RB, Fazio VW. Local treatment of squamous cell carcinoma of the anus. Surg Gynecol Obstet 1979; 148: 574-8. 11. O'Brien PH, Jenrette JM, Wallace KM, Metcalf JS. Epidermoid carcinoma of the anus. Surg Gynecol Obstet 1982; 155: 745-51. 12. Greenall MJ, Quan SHQ, Stearns MW, Urmacher C, DeCosse JJ. Epidermoid cancer of the anal margin. Pathologic features, treatment and clinical results. Am J Surg 1985; 149: 95-101. 13. Klotz RG, Pamukoglu T, Souillard DH. Transitional cloagenic carcinoma of the anal canal. Clinicopathological study of 373 cases. Cancer 1967; 20: 1727-45. 14. Kuehn PG, Eisenberg H, Reed JF. Epidermoid carcinoma of the perianal skin and anal canal. Cancer 1968; 22: 932-8. 15. Beahrs OH, Wilson SM. Carcinoma of the anus. Ann Surg 1976; 184: 422-8. 16. Singh R, Nime F, Mittelman A. Malignant epithelial tumours of the anal canal. Cancer 1981; 48: 411-5.
17. Papillon J. Rectal and Anal Cancers. Berlin: SpringerVerlag, 1982. 18. Schraut WH, Wang C, Dawson PJ, Block GE. Depth of invasion, location and size of cancer of the anus dictate operation treatment. Cancer 1983; 51: 1291-6. 19. Boman BM, Moertel CG, O'Connell MJ, Scott M, Weiland LH, Beart RW. Carcinoma of the anal canal. A clinical and pathologic study of 188 cases. Cancer 1984; 54: 114-25. 20. Clark J, Petrelli N, Herrera LM, Heimann A. Epidermoid carcinoma of the anal canal. Cancer 1986; 57: 400-6. 21. Frost DB, Richards PC, Montague ED, Giacco GG, Martin RG. Epidermoid cancer of the anorectum. Cancer 1984; 53: 1285-93. 22. Greenall MJ, Quan SHQ, DeCosse JJ. Epidermoid cancer of the anus. Br J Surg 1985; 72(Suppl.): S97-S103. 23. Nigro ND, Vaitkevicius VK, Considine B. Combined therapy for cancer of the anal canal: a preliminary report. Dis Colon Rectum 1974; 17: 354-6. 24. United Kingdom Co-ordinating Committee for Cancer Research (UKCCCRj Anal Cancer Trial Protocol. London: CRC Clinical Trials Centre, 1992. 25. Stearns MW, Ouan SH. Epidermoid carcinoma of the anorectum. Surg Gynecol Obstet 1970; 131: 953-7. 26. Pang LSC, Morson BC. Basaloid carcinoma of the anal canal. J Clin Patho/1967; 20: 128-35. 27. Daling JR, Weiss NS, Hislop TG, et al. Sexual practices, sexually transmitted diseases and the incidence of anal cancer. N Engl J Med 1987; 317: 973-7. 28. Palmer JG, Shepherd NA, Jass JR, Crawford LV, Northover JMA. Human papillomavirus type 16 DNA in anal squamous cell carcinoma. Lancet 1987; ii: 42. 29. Bauer HM, Hildesheim A, Schiffman MH, et al. Determinants of genital human papillomavirus infection in low-risk women in Portland, Oregon. Sex Transm Dis 1993; 20: 274-8. 30. Pao CC, Kao SM, Tang GC, Kun Lee JS, Ruan S. Human papillomavirus and cervical carcinoma in China and Taiwan. Lancet 1993; 342: 937.
© 1996 Blackwell Science Ltd, Surgical Oncology, 5: 65-68