Temporal Trends in Mortality From Diseases of the Circulatory System After Treatment for Hodgkin Lymphoma: A Population-Based Cohort Study in Sweden (1973 to 2006)

Abstract

Hodgkin lymphoma (HL) survival in Sweden has improved dramatically over the last 40 years, but little is known about the extent to which efforts aimed at reducing long-term treatment-related mortality have contributed to the improved prognosis. We used population-based data from Sweden to estimate the contribution of treatment-related mortality caused by diseases of the circulatory system (DCS) to temporal trends in excess HL mortality among 5,462 patients diagnosed at ages 19 to 80 between 1973 and 2006. Flexible parametric survival models were used to estimate excess mortality. In addition, we used recent advances in statistical methodology to estimate excess mortality in the presence of competing causes of death. Excess DCS mortality within 20 years after diagnosis has decreased continually since the mid-1980s and is expected to further decrease among patients diagnosed in the modern era. Age at diagnosis and sex were important predictors for excess DCS mortality, with advanced age and male sex being associated with higher excess DCS mortality. However, when accounting for competing causes of death, we found that excess DCS mortality constitutes a relatively small proportion of the overall mortality among patients with HL in Sweden. Excess DCS mortality is no longer a common source of mortality among Swedish patients with HL. The main causes of death among long-term survivors today are causes other than HL, although other (non-DCS) excess mortality also persists for as long as 20 years after diagnosis, particularly among older patients.