High-dose radiation therapy and neoadjuvant plus concomitant chemotherapy with 5-fluorouracil and cisplatin in patients with locally advanced squamous-cell anal canal cancer: final results of a phase II study.

Purpose: To analyse toxicity and response to a new scheme of neoadjuvant chemotherapy (CT) and concomitant radiochemotherapy (RT-CT) for locally advanced anal canal squamous-cell carcinoma (ACC).
Patients and Methods: Eighty patients with an ACC > 40 mm and/or with lymph node involvement were included (1 T1, 52 T2, 14 T3, 13 T4, 18 N0, 30 N1, 32 N2-N3). Two cycles of 5-fluorouracil (5-FU) and CDDP were delivered as neoadjuvant CT and two during RT-CT. Pelvic (+/- inguinal) RT delivered 45 Gy in 25 fractions of 1.8 Gy. Involved fields were boosted after a one to two month gap (15-20 Gy). The median follow-up was 29 months.
Results: One patient died of a pulmonary embolism on day 4. All patients received the entire treatment, with reduced 5-FU doses in 27% of the cases because of acute toxicity. Sixty-four grade 3 and five grade 4 toxicities were observed. No toxic death occurred. Complete response (CR) and partial response (PR) rates were, respectively, 10% and 51% after neoadjuvant CT, 67% and 28% after RT-CT and 93% and 5% after treatment completion (including 4 abdomino-perineal resections). The three-year actuarial overall, tumour-specific, colostomy-free, relapse-free, disease-free and event-free survivals were 86%, 88%, 73%, 70%, 67% and 63%, respectively.
Conclusions: Tolerance was good. After neoadjuvant CT, most of the patients were objective responders. After treatment completion, all but five achieved CR. The long-term results confirm the durability of local control and low toxicity on the sphincter. An ongoing phase III intergroup trial analyses the impact of neoadjuvant CT, and the benefit of a high-dose boost irradiation, on local control and colostomy-free survival.