Outcomes and prognostic factors for squamous-cell carcinoma of the anal canal: analysis of patients from the National Cancer Data Base.

Abstract

The objective of this study was to assess survival and prognostic factors for anal carcinoma in the population. Patients with squamous-cell carcinoma of the anal canal were identified from the National Cancer Data Base (1985-2000). Univariate and multivariable methods were used to assess factors associated with survival. Concordance was calculated to assess agreement between American Joint Committee on Cancer stage and actual outcome. Nineteen thousand one hundred ninety-nine patients with anal carcinoma were identified (Stage I, 25.3 percent; Stage II, 51.8 percent; Stage III, 17.1 percent; Stage IV, 5.7 percent). Overall five-year survival was 58.0 percent. The American Joint Committee on Cancer (6th edition) staging system provided good survival discrimination by stage: I, 69.5 percent; II, 59.0 percent; III, 40.6 percent; and IV, 18.7 percent (concordance index, 0.663). On multivariable analysis, patients with anal carcinoma had a higher risk of death if they were male, >or=65 years old, black, living in lower median incomes areas, and had more advanced T stage tumors, nodal or distant metastases, or poorly differentiated cancers (P < 0.0001). There was not a significant difference in survival by hospital type or year of diagnosis. Although tumor characteristics and staging affect prognosis, patient factors, such as gender, race, and socioeconomic status, are also important prognostic factors for squamous-cell carcinoma of the anal canal.