Classic Kaposi's sarcoma: Low-dose interferon alfa treatment

Background: Classic Kaposi's sarcoma, a rare form of cancer, has no definitive cure. A beneficial effect of low-dose interferon (IFN) alfa was indicated by some case reports. In the present report, we summarize the results of our experience with subcutaneous low-dose IFN alfa treatment of 11 patients with extensive classic Kaposi's sarcoma and review the literature. Design: Eleven patients, 56-96 years old, were treated: 10 men, 1 woman, 3 of whom had an associated malignancy. Subcutaneous injections of IFN alfa were given, starting with 3 million units 5 times a week, and modified according to side effects and response after 2 weeks (2-6 million units, 3-6 times a week). This treatment was continued for 6 months, except for 1 patient who died after 4 months and another who stopped treatment at 4 months due to surgery but was treated again after recurrence. Treatment was continued after 6 months when a partial response was noted, but further improvement was desired (1 patient). Results: In 9 out of the 11 patients, initial response was noted after 3-13 weeks of treatment. This was manifested by a reduction of lesion size and fading of color, leading to a partial resolution. Maximum response was achieved after 4-6 months. Remission lasted 4-72 months. Recurrences were retreated, with additional remissions after only 5-8 weeks of treatment. Side effects included fever and fatigue, which were overcome by dose reduction. Conclusion: Whereas in AIDS-related Kaposi's sarcoma patients become refractory to IFN, this was not observed in our patients with classic Kaposi's sarcoma. Moreover, unlike AIDS-related Kaposi's sarcoma, continuous treatment was not needed in classic Kaposi's sarcoma, and recurrences were responsive to retreatment.