Risk of disease recurrence and survival in patients with multiple myeloma: A German Study Group analysis using a conditional survival approach with long-term follow-up of 815 patients

Abstract

Background: Unlike the traditional method of overall survival prediction in patients with cancer, conditional survival predicts the survival of patients dynamically throughout the course of disease, identifying how a prognosis evolves over time. Methods: The authors assessed 815 consecutive patients with multiple myeloma through the German Study Group on Multiple Myeloma (Deutsche Studiengruppe Multiples Myelom; DSMM) incentive. Over 10 variables, including patient-specific and multiple myeloma–specific parameters, were analyzed at the time of initial diagnosis and repeatedly during follow-up. The probability of survival for another 5 years was calculated according to disease-related and host-related risks. Multivariate Cox models were used to determine baseline and updated prognostic factors for survival. Results: The median follow-up and overall survival were 10.3 years and 5.1 years, respectively. When comparing 5-year conditional survival probabilities from the data derived at the time of initial diagnosis with those updated over time, substantially differing prognoses were observed when follow-up data were used. Multivariate Cox regression models for cohorts surviving 0 to 5 years demonstrated hazard ratios (HRs) for patients aged <60 years, 60 to 69 years, and >70 years of 1, 1.68, and 3.17, respectively. These HRs for age were found to decline for patients surviving 5 years, as well as for those with advanced stages of disease (II/III) and unfavorable cytogenetics, whereas progressive disease remained an important factor in patients surviving 1 year, 3 years, and 5 years, with HRs of 1.85, 2.11, and 2.14, respectively. Conclusions: To the authors' knowledge, the current study is the first analysis of conditional survival in patients with multiple myeloma using both baseline and follow-up risk parameters, demonstrating that regular risk assessment throughout the course of disease and complete follow-up provide a more reliable conditional survival estimation than baseline assessment alone.