Trends in mantle cell lymphoma: Updated SEER analysis from 2000 to 2021.

Abstract

e19081 Background: Mantle Cell Lymphoma (MCL) is a rare subtype of Non-Hodgkin Lymphoma (NHL) that is characterized by cyclin-D1 overexpression. The Surveillance, Epidemiology and End Results (SEER) 22 database includes MCL data collected from 22 US states between 2000 and 2021. Previously, we reported prior SEER data that found the rate of MCL is declining since 2015 at a statistically significant rate. Here, we report an update on that data as well as subgroup analyses highlighting disparities in MCL outcomes. Methods: Statistical analysis was performed using the SEER*Stat platform and GraphPad. Age-adjusted incidence (per 100,000 Persons/Y) of reported MCL cases was extracted. We calculated the Annual Percent Change (APC) which is a standard way to characterize trends in MCL rates over time assuming the rates are to change at a constant percentage of the rate of the previous year. To compare trends in survival, we calculated the relative survival rate (RSR) as the ratio of the observed OS divided by the expected OS of an age-matched comparable group from the general population. Results: We found an initial increase in MCL incidence from 0.684 (2000-2004) to 0.786 (2005-2009) to 0.845 (2010-2014), followed by decreasing incidence from 0.828 (2015-2019) and to 0.783 (2020) and 0.778 (2021). While SEER reported 2021 incidence rates for all cancer sites were 9.4% higher compared to the 2020 incidence rates, that for MCL is 2.87% lower 2 . This indicates a real trend in MCL decline over time following the overall NHL downward trend. This is supported by the APC analysis as the MCL APC from 2000 to 2014 was +2.03% signaling an annual increase, that for the years 2015 to 2021 was -1.427% indicating an average -1.427% annual decline in MCL incidence since 2015. Subset analyses of race, income and stage were also performed. Median household income (inflation adjusted to 2022) is reported by RSR at 12 month intervals. We found a dose response relationship between survival and income at income intervals of $15,000. Unfortunately, the 5Y RSRs of Hispanic and American Indian populations continue to be significantly lower than other groups, reflecting continued disparities in access to healthcare or an overall worse prognosis in these patients. This contrasts with the 5Y RSRs of Black and API patients, which were among the lowest (47.3% and 46.7%, 2000-2004), but became the highest (67.2% and 67.8%, 2015-2019) reflecting not only a better access to healthcare, but also a shift to a previously unrecognized better overall prognosis of MCL in these patients. Conclusions: Our updated SEER analysis confirms that MCL incidence is declining over time and following the overall NHL downward trend. Our subset analyses establish a dose response relationship between survival and income. The improvement in RSR for Black and API patients could indicate an underlying favorable prognosis that was previously masked by disparities in healthcare access.