Editorial: Epidemiological trends in hematological malignancies

Abstract

Ou et al. performed a global population-based epidemiologic study of disease burden of chronic lymphocytic leukemia (CLL) in years 1990 to 2019 that included disability-adjusted life years (DALY) and age-standardized rates (ASR). They observed that CLL agestandardized incidence rate is growing worldwide, except in North America and Oceania. Also, unsurprisingly, the socio-demographic index (SDI) correlated with the burden of death and DALY. SDI is a measurement of country/regions development status that correlates with health outcomes. In low SDI quintiles, age-standardized death rate and age-standardized DALY rates went up, while decreasing significantly in high SDI quintiles. Presumably this disparity reflects access to newer and expensive medications, and to health care in general. Unfortunately, information from low SDI countries is limited and CLL incidence may be underestimated. Despite this intrinsic constraint, the paper illustrates what physicians everywhere know firsthand: social economic inequality is a major determinant of survival for patients with cancer, a sad determinant that is depicted here in the context of CLL.Tang et al. used the Surveillance, Epidemiology, and End Results (SEER) to describe epidemiologic, prognostic and treatment outcomes of patients with primary central nervous system lymphoma. The SEER Program is supported by the Unite States National Cancer Institute and provides information on USA cancer statistics (1). The authors showed that race, sex, age, marital status, surgical resection and chemotherapy were independently associated with survival. The paper reflects the power of large databases such as SEER, but also illustrates the limitations of such analyses. Detailed risk stratification and treatment aspects were not available, for example. But it is interesting to notice that single patients had worse survival than married patients, likely indicating the importance of support provided by a spouse caregiver. Patients identified as Black, despite representing only 7% of this cohort, also had shorter survival than White patients.Wu et al. also used SEER to review survival trends in patients under age 65 years with mantle cell lymphoma (years 1995-2016). They divided years of diagnosis in three eras: chemotherapy-alone (1995)(1996)(1997)(1998)(1999)(2000), intensified immunochemotherapy era (2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012) and targeted therapy era (2013-2016) and compared survival in these time frames. The patient population was predominantly white, but 5.8% were Black and 10.6% were Hispanic. In multi-variate analysis, male gender, age, and disease stage predicted survival, while race did Frontiers in Oncology frontiersin.org 01