Half-Body Irradiation in the Treatment of Multiple Myeloma: A Report of Nine Cases

We report the results of treatment of 9 patients with advanced multiple myeloma (MM) using half-body irradiation. Six nonresponders to chemotherapy received it as consolidation therapy after the plateau phase of MM had been observed, and 4 patients received it as salvage therapy of refractory or relapsing MM. One of the patients received it twice, first as consolidation and later during the course of her disease also as salvage therapy. Objective response was obtained in 1 of 6 patients who received half-body irradiation as consolidation therapy and in 3 of 4 patients who received it as salvage therapy. Responders to half-body irradiation generally achieved a longer relapse-free interval. Treatment with half-body irradiation was especially effective in combination with human leukocyte interferon as salvage therapy in 2 of the patients with refractory MM, leading to a relapse-free interval of more than 27 months in one of them. Symptomatic relief was observed in 5 of 6 patients. All had transient post-irradiation pancytopenia, with pneumonitis, nausea and vomiting observed in those who had the upper half of the body irradiated first. It is thus our opinion that half-body irradiation should not be used as consolidation therapy in nonresponders to chemotherapy, because it causes undue toxicity to heavily pretreated patients. Its role in the treatment of refractory or relapsing MM in combination with human leukocyte interferon should be fully evaluated.