This study assesses whether new treatment strategies developed in clinical trials translate into improved survival for multiple myeloma (MM) patients in the Netherlands. All patients diagnosed with MM in the Northern part of the Netherlands between 1989 and 2005 were retrieved from two regional population-based cancer registries. Information on study participation was derived from linkage with trial information systems. The effect of period of diagnosis (1989-1992, 1993-1996, 1997-2000, 2001-2005), age (<50, 50-65, 66-74, 75), gender, Salmon-Durie (SD) stage, trial participation and treatment on relative survival were studied. In total 4985 patients were included. When trial participation was analysed for exact periods in which trials were open, 16% of patients aged 65 years with SD-stage I and 38% with SD-stage II or III were enrolled compared to 2% of patients aged >65 years with SD-stage I and 5% with SD-stage II or III. Relative survival decreased with age (p<.001), with advanced stage (p<.001) and was better for patients enrolled in trials (p<.001). Five-year relative survival increased from 34% (95% confidence interval (95% CI) 28-39%) in 1989-1992 to 56% (95% CI 50-61%) in 2001-2005 for patients 65 years. The excess mortality was 37% lower in 2001-2005 than in 1989-1992 for these patients, adjusted for age, stage, trial participation and gender (p<.001). Survival did not improve for older patients.
In conclusion: MM survival improved among younger but not among older patients since the mid-1990s. The improved survival of younger patients coincided with increasing trial participation and increasing use of high-dose chemotherapy and autologous stem-cell transplantation.