Cause-specific mortality among Medicare beneficiaries with newly diagnosed non-Hodgkin lymphoma subtypes

As the US population ages and non-Hodgkin lymphoma (NHL)-specific mortality declines, deaths from causes other than NHL will become increasingly important in treatment decision making for older patients with NHL. The objective of the current study was to describe how the 5-year cumulative incidence of NHL-specific and other-cause mortality varies by subtype, age, comorbidity level, and time since diagnosis in older patients.

Using the Surveillance, Epidemiology, and End Results cancer registry data linked to Medicare claims, patients aged ≥66 years were identified at the time of diagnosis with a first, primary NHL diagnosis from 2004 through 2013. Death certificate data and Fine-Gray competing risks models were used to estimate the 5-year cumulative incidence of NHL-specific and other-cause mortality by NHL subtype, age, and comorbidity level. Estimates were displayed over time using stacked cumulative incidence curves.

Among 30,666 patients with NHL, 32% died of NHL and 13% died of other causes within 5 years of diagnosis. The cumulative incidence of other-cause mortality increased with age and comorbidity level for all subtypes. Among patients with aggressive NHL subtypes, NHL-specific mortality exceeded other-cause mortality across all age groups, comorbidity levels, and number of years after diagnosis. For patients with indolent NHL subtypes, other-cause mortality was similar to or exceeded NHL-specific mortality, especially among older patients with severe comorbidity or with the indolent marginal zone, lymphoplasmacytic, and mycosis fungoides subtypes.

The findings of the current study suggest that mortality from causes other than NHL are important for patients of an older age, with a higher comorbidity level, and with indolent disease. Evidence from the current study can guide the development of tools for estimating individual prognosis that inform treatment discussions in patients with NHL.