Time-dose considerations in the treatment of anal cancer.

PURPOSE: To analyze the impact of patient and treatment parameters in concurrent chemoradiation treatment for anal carcinoma. METHODS AND MATERIALS: Retrospective review of 50 MO anal cancer patients treated from 1984-1994. Most patients received concurrent 5-FU, mitomycin, and radiation. Local control and disease-free/overall survival were determined and analyzed according to patient and treatment parameters. RESULTS: With 43 month median follow-up, projected overall survival is 66% at 5 and 8 years. Disease-free survival is 67% at 5 years and 59% at 8 years. Local control is 70% at 5 and 8 years. Doses of > or =54 Gy are associated with improved 5-year survival (84 vs. 47%, p = 0.02), disease-free survival (74 v. 56%, p = 0.09), and local control (77 vs. 61%, p = 0.04). Although local control, disease-free survival, and overall survival were improved in patients whose overall treatment time was <40 days, this was not statistically significant. Outcome in the four patients with pretreatment hemoglobin (Hgb) <10 appeared worse with 3-year overall survival 50 vs. 68% (p = 0.07), disease-free survival 0 vs. 67% (p = 0.11), and local control 0 vs. 74% (p = 0.05). Projected 5-year overall survival, relapse-free survival, and local control in 4 HIV(+) patients is 0, 75, and 75%. Multivariate analysis reveals that dose (p = 0.02) and Hgb (p = 0.05) independently affect local control, dose (p = 0.02) affects disease-free survival, and dose (p = 0.01), Hgb (p = 0.03), T-stage (p = 0.03), and HIV-status (0.07) independently influence overall survival. CONCLUSION: Radiation doses of > or =54 Gy are associated with significantly improved survival and local control in anal cancer patients treated with chemoradiation. Overall treatment times of less than 40 days are associated with a trend towards improved outcome, but this is not significant. Pretreatment hemoglobin <10 is associated with worse treatment outcome. Survival of HIV (+) patient is poor, but the majority of such patients in this series died of intercurrent disease with their anal carcinomas controlled by chemoradiation.

Duke Scholars

Author Christopher G. Willett Radiation Oncology