RADIATION-THERAPY FOR THE PALLIATION OF MULTIPLE-MYELOMA

Purpose: This study reviews the experience at the University of Arizon a in an effort to define the minimum effective radiation dose for dura ble pain relief in the majority of patients with symptomatic multiple myeloma. Methods and Materials: The records of 101 patients with multi ple myeloma irradiated for palliation at the University of Arizona bet ween 1975 and 1990 were reviewed. Three hundred sixteen sites were tre ated. Ten sites were asymptomatic, including six hemibody fields with advanced disease unresponsive to chemotherapy and four local fields wi th impending pathological fractures. Three hundred six evaluable sympt omatic sites remained. The most common symptom was bone pain. Other sy mptoms included neurological impairment and a palpable mass. Results: Total tumor dose ranged from 3.0 to 60 Gy, with a mean of 25 Gy. Sympt om relief was obtained in 297 of 306 evaluable symptomatic sites (97%) . Complete relief of symptoms was obtained in 26% and partial relief i n 71%. Symptom relief was obtained in 92% of sites receiving a total d ose less than 10 Gy (n = 13) and 98% of sites receiving 10 Gy or more (n = 293). No dose-response could be demonstrated. The likelihood of s ymptom relief was not influenced by the location of the lesion or the use of concurrent chemotherapy. Of the 297 responding sites, 6% (n = 1 9) relapsed after a median symptom-free interval of 16 months. Neither the probability of relapse nor the time to relapse was related to the radiation dose. Retreatment of relapsing sites provided effective pal liation in all cases. Conclusion: Radiation therapy is effective in pa lliating local symptoms in multiple myeloma. A total dose of 10 Gy sho uld provide durable symptom relief in the majority of patients.