Anal carcinoma: a 15-year retrospective analysis

Using a 15-year experience in two teaching hospitals to illustrate the clinicopathologic, treatment and survival characteristics of cloacogenic and squamous cell carcinoma of the anus.

A retrospective analysis over a 15-year period from St Vincent's Hospital (SVH) and the Catholic Medical Center (CMC) in New York City. The patients in the study all had a diagnosis of either squamous or cloacogenic cell carcinoma of the anus.

Cloacogenic and squamous cell carcinoma accounted for 2.5% of all large bowel cancers. In the population sample, 28/92 (30.4%) were of the cloacogenic type and 64/92 (69.6%) were of the squamous cell type. The male-to-female ratio was 1:1.5 in those with cloacogenic cancer and 1.8:1 in those with squamous cell carcinoma. The mean age of presentation was 57 +/- 2.8 years for the squamous cell carcinoma patients and 66.3 +/- 3.4 years in those with cloacogenic carcinoma (P < 0.02); 3/28 (10.7%) of patients with cloacogenic cancer were human immune deficiency virus (HIV) positive while 15/64 (23.4%) of the squamous cell cancer patients were HIV positive. The most common clinical presentation in both groups were rectal bleeding, pain, constipation and the presence of an anal mass. Of patients with squamous cell cancer 25% had evidence of infection with the human papilloma virus (HPV) while none of those with cloacogenic cancer had evidence of HPV infection (P < 0.0005). The treatment modality and survival were similar in both histologic groups. The most important factors that affect survival in both groups are female sex and stage of disease.

Cloacogenic and squamous cell carcinoma account for only a small proportion of large bowel cancers. The squamous cell type is the more common type and presents at a younger age in both sexes. The squamous cell type is also more common in males and is associated with human papilloma and HIV infection. Treatment modality and survival is, however, similar in both histologic variants of anal cancer.