Preliminary report on long-term results of pion therapy at Los Alamos

Between 1974 and 1981 a group of 234 patients with generally advanced regional cancers were treated with pions at the Los Alamos Meson Production Facility (LAMPF). As of May 1983, 53 patients remained alive of which 31 were examined. Records on these and others were reviewed in order to assess some late effects of pion therapy. In judging clinical RBE values there appeared to be no difference between acute and late effect RBE's. Complications were clearly dose-related and significantly greater in patients who received additional local photon irradiation and/or surgery. Tumor control also appeared dose related but difficult to assess because of a wide range of fractionation numbers.