Cause-specific mortality in survivors of lymphoplasmacytic lymphoma (LPL) and waldenstrom macroglobulinemia (WM).

Abstract

e19056 Background: LPL and WM are rare, indolent mature B-cell lymphomas. While recent studies reveal improving survival after LPL/WM, cause-specific mortality has not been comprehensively studied. Methods: We identified 6659 adults with first primary LPL (n = 2866) or WM (n = 3793) within 17 US population-based cancer registries from 2000 to 2015. Patients were followed for vital status (mean follow-up = 5.07 years), and causes of death were determined from death certificates. Standardized mortality ratios (SMRs) estimated relative risk of death compared to the general population. We estimated cumulative mortality and absolute excess risk (AER) per 10,000 person-years. Results: We observed 2826 deaths overall, of which 43%, 13%, and 42% were due to lymphoma, cancers excluding lymphoma, and non-malignant causes, respectively. There was a 20% higher risk of death due to non-malignant causes compared to the general population (n = 1194, SMR = 1.2, 95% confidence interval [CI] = 1.1 to 1.2). The most common non-malignant causes included infectious (n = 162, SMR = 1.8, 95% CI = 1.5 to 2.1, AER = 21.0), respiratory (n = 131, SMR = 1.2, 95% CI = 1.0 to 1.5, AER = 7.4), and digestive (n = 76, SMR = 1.9, 95% CI = 1.5 to 2.4, AER = 10.7) diseases. Cause-specific mortality varied by time since and age at LPL/WM diagnosis. Risks were highest in the first year after LPL/WM for non-malignant causes (SMR = 1.4, AER = 34.3), particularly infections (SMR = 2.4, AER = 34.4) and non-neoplastic hematologic diseases (SMR = 17.3, AER = 20.7). In contrast, risk of death due to cancers excluding lymphoma increased with time since diagnosis (SMR< 1y = 1.2, SMR≥5y = 1.7; AER< 1y = 15.1, AER≥5y = 60.0). Analyses by age, focused on AERs, showed generally similar risks across age groups (cancers excluding lymphoma: AER< 65= 26, AER65-75= 28, AER≥75= 31; non-malignant causes: AER< 65= 52, AER65-75= 66, AER≥75= 23). Cumulative mortality from non-malignant causes (23.7%) exceeded that from lymphoma (22.9%) beginning 9 years after LPL/WM diagnosis. Conclusions: Using population data, we identified areas to improve survivorship care of LPL/WM patients, particularly for non-malignant causes of death.