Initial results of a phase II trial of high dose radiation therapy, 5-fluorouracil, and cisplatin for patients with anal cancer (E4292): an Eastern Cooperative Oncology Group study.

PURPOSE

A prospective clinical trial was performed to assess the response and toxicity associated with the use of high dose radiation therapy, 5-fluorouracil, and cisplatin in patients with anal cancer.

METHODS AND MATERIALS

Patients with anal cancer without distant metastasis were eligible for this study. Radiation therapy consisted of 59.4 Gy in 33 fractions; a 2 week break in treatment was taken after 36 Gy had been given. A treatment of 5-fluorouracil, 1,000 mg/m2 per day intravenously, was given for the first 4 days of radiation therapy, and cisplatin, 75 mg/m2 intravenously, was given on day 1 of radiation therapy. A second course of 5-fluorouracil and cisplatin was given after 36 Gy of radiation, when the radiation therapy was resumed.

RESULTS

Nineteen patients entered this study and received treatment. Thirteen (68%) had a complete response, 5 (26%) had a partial response, and 1 (5%) had stable disease. The patient with stable disease and one of the patients with a partial response had complete disappearance of tumor more than 8 weeks after completion of radiation therapy. Fifteen patients had toxicity of Grade 3 or higher: the worst toxicity was Grade 3 in eight patients, Grade 4 in six patients, and Grade 5 in one patient. The most common form of toxicity of Grade 3 or higher was hematologic. The one lethal toxicity was due to pseudomembranous colitis, which was a complication of antibiotic therapy for a urinary tract infection.

CONCLUSION

Radiation therapy, cisplatin, and 5-fluorouracil resulted in an overall response rate of 95%. Significant toxicity occurred, an indication that this regimen is near the maximal tolerated dose. A Phase III clinical trial is planned in which radiation therapy, cisplatin, and 5-fluorouracil will be used as an experimental arm.