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

Abstract

Purpose: The objective of this study was to assess survival and prognostic factors for anal carcinoma in the population.

Methods: 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.

Results: 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.

Conclusion: 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.