Primary chemoradiation therapy with fluorouracil and cisplatin for cancer of the anus: results in 35 consecutive patients.

Purpose: This prospective phase II study was designed to test the activity and toxicity of a regimen of fluorouracil (5-FU) and cisplatin (CDDP) in combination with radiation therapy in the treatment of epidermoid cancer of the anal canal.
Patients and Methods: Thirty-five consecutive patients with untreated epidermoid cancer of the anal canal were candidates for chemoradiation therapy (CRT). Staging of cancer was as follows: T1, 26%; T2, 60%; T3, 14%; and N1, 2,3, 26%. No patient had distant metastases. The treatment protocol consisted of two to three cycles of chemotherapy starting on days 1 and 21 and concurrent radiotherapy at a daily dose of 1.8 Gy up to a total dose of 36 to 38 Gy in 4 weeks, delivered to the anal region, perineum, middle and lower pelvis, and inguinal and external iliac nodes. Radiotherapy was then delivered to the anoperineal region and metastatic inguinal nodes to a total dose of 18 to 24 Gy in 10 fractions. Chemotherapy consisted of 24-hour intravenous (IV) infusion of 5-FU 750 mg/m2 on days 1 to 4 and CDDP 100 mg/m2 by 60-minute IV infusion on day 1.
Results: All patients received two cycles of chemotherapy; the second was delayed in three patients because of leukopenia that was evident in 11 (31%). In eight patients, a third cycle was added. They all experienced nausea or vomiting; one patient showed signs of cardiotoxicity and one developed proctitis, dermatitis, and diarrhea (grade 3). Complete regression (CR) was assessed in 33 patients (94%); nine patients with metastatic lymph nodes also had CR. Two patients had a partial response (PR); both underwent abdominoperineal resection, which was not curative in one. Two patients (6%) had a local recurrence; in one, this was associated with hepatic metastases. One of these patients underwent surgery and is alive after about 4 years, while the other is undergoing chemotherapy. After a median follow-up duration of 37 months, 94% of patients are alive without evidence of disease and 86% are colostomy-free.
Conclusion: This regimen is well tolerated; its toxicity does not exceed that observed with the combination of 5-FU and mitomycin (MMC). Compared with our previous experience based on the classic CRT (5-FU, MMC, and radiation), the objective response rate observed with this new combination was similar. However, the local recurrence rate, observed in patients treated with the new regimen, was lower (6% v 24%). According to more recent data from the literature, primary CRT is the elective indication in epidermoid cancer of the anus and replacement of MMC with CDDP seems an effective and logical evolution.