In recent years, survival of patients with multiple myeloma (MM) has markedly improved as a result of the introduction of several novel therapies, with an in increment in overall survival (OS) of up to 80% at 4 years. However, the majority of the reported data originates from clinical trials which are subject to bias, by including mainly optimal patients and treatment conditions. Managing MM in Colombia and other low and middle-income countries can be challenging due to delays on diagnosis and treatment, as well as health care access barriers. RENEHOC is a retrospective-prospective registry documenting diagnosis, treatment characteristics and outcomes in hematologic neoplasias in Colombia, supported by ACHO.
The aim of the present study is to estimate survival rates of MM patients in an unselected population and analyze possible factors associated with these outcomes.
An ambispective multicentric study was conducted based on data collected by RENEHOC during 2018, by centers in the most populated areas in Colombia. Descriptive statistics were used to analyze patient's demographic and clinical characteristics. The Kaplan-Meier method was used to assess overall (OS) and disease-free survival (DFS) rates. Hazard Ratios (HR) using Cox proportional regression modeling was estimated. Variables considered as prognostic factors for analysis were: Sex, age, time from onset symptoms to diagnosis (TSD), induction chemotherapy, ISS, Durie-Salmon (DS), type of monoclonal component and consolidation with autologous transplant (ASCT).
We present data from 334 patients. Mean age at diagnosis was 64.4 years (SD ± 11.09); 55.9% were male. The most common symptoms at diagnosis were bone pain (76.6%), anemia (59.5%) and pathological fractures (43.1%). Mean time TSD was 10.3 months (SD ± 10.8). Renal failure was present in 25.1% of cases; 34% of them required dialysis. IgG was the most common monoclonal component (52.7%). Molecular cytogenetic prognostic characterization was available only in 20% (n = 67). The majority of patients were staged as advanced by DS (DS IIIA or IIIB: 64%, N = 214) and high-risk by ISS (ISS 1: 15.3%, ISS 2: 24.8%, ISS 3: 31.4%, unknown: 28.1%). Nine patients received radiotherapy as first-line treatment and 235 chemotherapy. The most common induction regimens were CyBorD (53%), VTD (15%), Bortezomib-dexa (7%), and VISTA (6%). Partial response or better was achieved in 67% of the patients after first-line, without significant differences in response between regimens. Only 25% (n = 83) of the patients received ASCT as consolidation therapy in first line. 7% (n = 24) were transplanted latter. 24% (n = 80) were considered to elegible but could not undergo ASCT due to administrative barriers.
Median OS and DFS were 56.5 and 46 months. Survival rates were superior in patients treated with triplet combinations (CyBorD 56.2 and 55; VTD 46.3 and 46; Vd 31.6 and VISTA 36.6 and 28 months). At 5 years, OS was 76.8% and DFS was 73.2%. On multivariate analysis, the only factor associated with improvement in OS was ASCT as consolidation (HR 0.34; p = 0.001, CI 0.17-0.66).
OS and DFS were similar to the outcomes reported in the existing literature mainly assessed in high-income countries. ASCT as consolidation therapy was the only factor affecting survival. Health care access barriers played an important role on prolonged TSD, low rate of prognostic evaluation and low rates of transplantation in patients otherwise eligible for it. Efforts such as RENEHOC allows us to identify flaws in patient care that affect prognosis, and start efforts to correct them.