Malignant tumors of the anal canal: The spectrum of disease, treatment, and outcomes

BACKGROUND. Cancers of the anal canal are a rare and diverse group of tumors of the gastrointestinal tract currently managed most often with surgery, chemoradiotherapy, or both. Previous investigations of cancer of the anal canal have reported on small numbers of patients, included only squamous histology, or included a select group of patients. The current study reviewed a large consecutive series of patients with cancer of the anal canal, including all histologies, who received chemoradiotherapy as the primary treatment modality. METHODS. The spectrum of pathology, treatment, and outcomes for 192 patients with malignant tumors of the anal canal over a 10- year period, from 1984 to 1994, was analyzed. Patient charts were reviewed for diagnosis, staging, treatment, survival, and recurrence rates. RESULTS. The pathologies of 192 patients (mean age, 58 years; 119 females and 73 males) included 143 (74%) with squamous cell carcinoma, 36 (19%) with adenocarcinoma, and 7 (4%) with melanoma. The remaining 6 patients (3%) were diagnosed with neuroendocrine tumors (2), carcinoid tumor (1), Kaposi sarcoma (1), leiomyosarcoma (1), or lymphoma (1). T classification distributions were T1 (3%), T2 (46%), T3 (28%), and T4 (12%). The overall crude 5-year survival and recurrence rates were 53% and 34%, respectively. Five-year survival rates were 57% for squamous cell carcinoma, 63% for adenocarcinoma, and 33% for melanoma. Five-year survival rates by T classification were T1 (62%), T2 (57%), T3 (45%), and T4 (17%). Twenty-one (15%) of the patients with squamous cell carcinoma underwent surgical therapy only, with a 5-year survival rate of 60% and a recurrence rate of 23% at 5 years. The remaining 122 patients (85%) with squamous cell carcinoma received chemoradiotherapy only, with a 5- year survival rate of 55% and a recurrence rate of 34% at 5 years. Salvage abdominal perineal resection for recurrent or persistent squamous cell carcinoma after chemoradiotherapy was performed on 13 patients, with 8 (62%) of them alive at a mean follow-up of 32 months. Twenty-two patients (61%) with adenocarcinoma of the anal canal were treated with surgery, and 14 patients (39%) underwent surgery with adjuvant chemoradiation therapy. The 5- year survival and recurrence rates were 63% and 21%, respectively. CONCLUSIONS. Chemoradiotherapy for patients with squamous cell carcinoma offers survival rates equivalent to surgical therapy and preserved sphincter function. Adenocarcinoma managed with surgery, with adjuvant therapy for selected patients, gives good results. Melanoma continues to be associated with a poor prognosis.