A phase II study of 13-cis retinoic acid plus interferon alpha-2a in advanced stage penile carcinoma: an Eastern Cooperative Oncology Group study (E3893).

PURPOSE

Combined biological therapy with 13-cis-retinoic acid (13-cRA) and interferon alpha-2a (IFN alpha-2a) was reported to be highly effective in squamous cell carcinoma of the cervix and skin. Squamous cell carcinoma of the penis is rare in the United States, accounting for less than 1/2% of all male malignancies. Because of the association of infection with human papillomavirus with both carcinomas of the cervix and penis and their shared squamous cell histology, we carried out a phase II study of 13-cRA and IFN alpha-2a in carcinoma of the penis.

MATERIALS AND METHODS

Eighteen ambulatory patients with surgically unresectable, recurrent, and/or metastatic squamous cell carcinoma of the penis were treated with IFN alpha-2a, 3MU/day administered subcutaneously and 13-cRA, 1 mg/kg orally daily for at least eight weeks, unless intolerable toxicity occurred.

RESULTS

One patient was ineligible; one patient withdrew prior to treatment. Among the 16 eligible, treated patients, there was one complete response. Fourteen patients had progressive disease as their only treatment effect. Two patients were unevaluable for tumor response because they had no follow-up tumor measurements. No unexpected treatment-related toxicities were found on study. The only common form of grade 3 toxicity was hypertriglyceridemia found in eight of the 17 patients (47%). No toxicities above grade 3 were observed.

CONCLUSION

In contrast to its benefit in squamous cell carcinomas of the cervix and skin, the combination of 13-cRA and IFN alpha-2a has low efficacy in advanced carcinoma of the penis.