Second primary malignancy after multiple myeloma-population trends and cause-specific mortality.

Area of Science:

• Hematology
• Oncology
• Cancer Epidemiology

Background:

• Multiple myeloma (MM) management has evolved with autologous hematopoietic cell transplantation (AHCT) and novel agents.
• AHCT and lenalidomide maintenance are linked to an increased risk of second primary malignancy (SPM).

Purpose of the Study:

• To analyze the trends in SPM risk and mortality among MM patients across different treatment eras.
• To assess the impact of evolving MM therapies on SPM incidence and cause-specific mortality.

Main Methods:

• Utilized Surveillance, Epidemiology, and End Results (SEER) 13 registries data for 9,833 MM patients diagnosed <65 years.
• Analyzed three eras: 1995-99 (pre-thalidomide/AHCT), 2000-04 (post-thalidomide/pre-lenalidomide/bortezomib), and 2005-09 (post-novel agents).
• Assessed SPM risk using standardized incidence ratios (SIR) and cause-specific mortality.

Main Results:

• Cumulative incidence of SPM at 90 months increased from 4.7% to 6.3% across the eras (P=0.0008).
• SIR for hematological malignancies (acute leukemias, lymphomas) in years 1-5 and 6-10 increased significantly over time.
• Overall mortality in MM patients declined sharply, with no increase in SPM-related death risk.

Conclusions:

• The evolution of MM therapy, including AHCT and novel agents, is associated with a population-level increase in SPM risk.
• Despite increased SPM risk, there is no discernible effect on the risk of death from SPM.
• Therapeutic advancements in MM have improved survival without increasing SPM-related mortality.