Are the current criteria for response useful in the management of multiple myeloma?

One hundred seventy-three patients with multiple myeloma were treated from the time of diagnosis with standard oral melphalan and prednisone at 28-day intervals until they became refractory to treatment. Response to treatment was determined according to the Chronic Leukemia-Myeloma Task Force (TF) criteria, and independently according to the Southwest Oncology Group (SWOG) criteria. Survival by disease stage and response according to the two sets of criteria were analyzed for patients living longer than 3 months. The median survival of responding and nonresponding (TF criteria) stage II patients was 43.8 and 40.3 months, respectively (P = .29). By SWOG criteria, median survival for responding and nonresponding stage II patients was 48.3 and 39.0 months, respectively (P = .12). In stage III patients, median survival for responders and nonresponders (TF criteria) was 34.0 and 21.7 months, respectively (P = .01), compared with 35.5 and 24.4 months (P = .04) by SWOG criteria. These data would suggest that the TF criteria predicts a survival disadvantage only in very advanced myeloma and that applying the stricter limits for the definition of response of the SWOG does not further aid in selecting a subgroup of myeloma patients with poorer survival.