Purpose: This study contained herein assessed long-term results, toxicity, and prognostic variables following combined modality therapy of patients with International Union Against (Cancer Classification T1-4, N0-3, M0 squamous-cell carcinoma of the anal canal.
Patients and methods: Between 1985 and 1996, 62 patients completed treatment with combined modality therapy. A median total dose of 50 Gy was given to the primary, perirectal, presacral, and inguinal nodes followed by a local boost in selected cases. 5-Fluorouracil was scheduled as a continuous infusion of 1,000 mg/m2 per 24 hours on days 1 to 5 and 29 to 33 and mitomycin C as a bolus of 10 mg/m2 on days 1 and 29. Routinely processed paraffin-embedded sections were stained using monoclonal antibodies for detection of proliferating cell nuclear antigen and MIB1 (Ki-67) antigen to determine the labeling index. In addition, DNA ploidy was assessed after Feulgen staining.
Results: Actuarial cancer-related survival, no evidence of disease survival, and colostomy-free survival rates at five years were 81, 76, and 86 percent, respectively. In univariate analysis, T category (T1/2 vs. T3/4) was predictive for no evidence of disease survival (87 vs. 59 percent; P = 0.03) and colostomy-free survival (94 vs. 73 percent; P = 0.05). N category (N0 vs. N1-3) influenced actuarial cancer-related survival (85 vs. 58 percent; P = 0.002) and no evidence of disease survival (80 vs. 53 percent; P = 0.02). A higher proliferative potential as measured by the MIB1 labeling index was associated with a better colostomy-free survival (90 vs. 50 percent; P = 0.04). In multivariate analysis, actuarial cancer-related survival was only influenced by the N category (P = 0.03) and no evidence of disease survival by N category (P = 0.03) and mitomycin C dose (P = 0.04). Salvage abdominoperineal resection achieved long-term control in only four of seven patients with local failures.
Conclusion: Treatment with a combination of radiotherapy and chemotherapy is safe and effective for patients with anal canal carcinoma. Abdominoperineal resection is indicated as a salvage procedure in nonresponding and recurrent lesions and may be of benefit in a small subgroup of patients with poor prognostic factors.