Prognostic factors in anal squamous carcinoma: a multivariate analysis of clinical, pathological and flow cytometric parameters in 235 cases.

Clinical, pathological and flow cytometric parameters have been analysed by univariate and multivariate analysis to define those parameters of important prognostic influence in 235 cases of surgically treated squamous carcinoma of the anus and perianal skin. Patients had been treated by anorectal excision (166 patients) or by local excision (69). Analyses were carried out on five data sets--the two surgical subgroups, two groups distinguished by site of tumour and on all 235 patients. Univariate analysis showed many parameters to be of prognostic influence, although histological typing of tumours into the more common histological subtypes was of no prognostic value. Parameters of independent prognostic significance in multivariate analysis were those indicating depth of spread, inguinal lymph node involvement and DNA-ploidy. In this study the subdivision of the rarer types of anal canal tumour, such as mucoepidermoid carcinoma, microcystic squamous carcinoma and small cell anaplastic carcinoma, was relevant confirming that these tumours have a poor prognosis. It is now felt that surgery should not be employed as primary treatment in most cases of anal cancer and the results of this study have to be interpreted with caution when applied to patients treated with radiotherapy with or without chemotherapy. Nevertheless, our findings suggest that the most useful prognostic information can be gleaned from accurate clinical staging and an assessment of DNA-ploidy status.