Mitomycin C as an adjunct to postoperative radiation therapy in squamous cell carcinoma of the head and neck: results from two randomized clinical trials.

PURPOSE

This study was undertaken to assess the benefit of mitomycin C as an adjunct to postoperative radiation therapy in patients with operable squamous cell carcinoma of the head and neck.

METHODS AND MATERIALS

Between May 1980 and May 1991, 182 patients have been enrolled in two consecutive randomized clinical trials testing mitomycin C as an adjunct to radiation therapy in squamous cell carcinoma of the head and neck. In both trials, patients were stratified by stage, disease site and intent of therapy. This subset analysis includes 113 patients entered into these two randomized trials treated with surgery and postoperative radiation therapy. In the first trial, patients were randomized to receive standard postoperative radiation therapy alone compared with postoperative radiation therapy with concomitant mitomycin C. In the second trial, patients were randomized to postoperative radiation therapy or postoperative radiation therapy with concomitant mitomycin C plus dicoumarol.

RESULTS

As of November 1991, the 113 patients treated with surgery and postoperative radiation therapy in both trials had a median follow-up of 93 months. There have been a total of 12 local recurrences in the radiation therapy alone arm compared to 0 local recurrences in the radiation therapy/mitomycin C arm. There were eight regional recurrences in the radiation therapy alone arm compared with five regional recurrences in the mitomycin C arm. Patients in the mitomycin C arm experienced a superior 5-year actuarial local regional control rate (87% vs. 67%, p < .015) and a statistically significant disease-free survival benefit (67% vs. 44%, p < .03). Overall survival difference between the two arms (56% vs. 41%) has not reached statistical significance.

CONCLUSIONS

We conclude from these prospectively designed randomized clinical trials that in patients with operable head and neck cancer treated with surgery and postoperative radiation therapy, concomitant administration of mitomycin C with radiation therapy will result in a statistically significant disease-free survival and local regional control benefit. We are currently investigating the value of other bioreductive alkylating agents as adjuncts to radiation therapy in patients with squamous cell carcinoma of the head and neck.