Induction therapy for poor-prognosis anal canal carcinoma: a phase II study of the cancer and Leukemia Group B (CALGB 9281).

PURPOSE: Although most patients with anal canal cancer are cured with sphincter-preserving, nonsurgical, combined-modality therapy, those with large tumors and lymph node involvement have a poor prognosis. To establish the safety and efficacy of induction chemotherapy with infusional fluorouracil (FU) plus cisplatin followed by FU plus mitomycin C with concurrent radiation in patients with poor-prognosis squamous cell cancers of the anal canal.
METHODS: Patients with previously untreated anal canal cancers with T3 or T4 tumors and/or extensive nodal involvement (bulky N2 or N3) received two 28-day cycles of induction treatment with infusional FU plus cisplatin followed by two 28-day cycles of FU plus mitomycin C with concurrent split-course radiation. A third cycle of FU and cisplatin with radiation boost was given to patients with persistent primary site disease or bulky N2 or N3 disease at presentation.
RESULTS: Forty-five assessable patients received protocol therapy. Treatment was generally well tolerated, and gastrointestinal and hematologic toxicities were the most common. Induction chemotherapy resulted in eight complete and 21 partial responses. After induction, combined-modality, and boost therapy, 37 (82%) of 45 assessable high-risk patients achieved a complete response. After 4 years of follow-up, 68% of patients are alive, 61% are disease-free, and 50% are colostomy- and disease-free.
CONCLUSION: A combined-modality approach that includes induction treatment with FU and cisplatin followed by combined-modality therapy with FU, mitomycin C, and concurrent radiation results in long-term disease control in the majority of patients with poor-prognosis anal canal cancer.