Purpose: Balancing disease control and toxicity from chemotherapy and radiotherapy (RT) when treating early-stage classical Hodgkin lymphoma (cHL) is important. Available data on long-term toxicity after RT for cHL mostly refer to RT techniques no longer in use. We aimed to describe long-term toxicity from modern limited-field (LF)-RT after two or four cycles of doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD).
Patients and methods: This study included all patients with cHL treated with two or four cycles of ABVD and 30 Gy LF-RT during 1999-2005 in Sweden. Patients (n = 215) and comparators (n = 860), matched for age, gender, and region of residence, were cross-checked against national health registries for malignancies, diseases of the circulatory system (DCS), and diseases of the respiratory system (DRS) from the day of diagnosis of cHL.
Results: The risk of a malignancy was higher for patients than comparators, hazard ratio (HR) 1.5 (95% CI, 1.0 to 2.4), as was the risk for DCS 1.5 (95% CI, 1.1 to 2.0) and for DRS 2.6 (95% CI, 1.6 to 4.3). The median follow-up was 16 years (range, 12-19 years). Of individual diagnoses in DCS, only venous thromboembolism was statistically significantly elevated. If the first 6 months (ie, time of active treatment for cHL) were excluded and censoring at relapse of cHL or diagnosis of any malignancy, the increased HR for venous thromboembolism diminished. Most of the excess risk for DRS consisted of asthma, HR 3.5 (95% CI, 1.8 to 6.8). Patients diagnosed with DRS were significantly younger than comparators.
Conclusion: Compared with toxicity from earlier RT techniques, excess morbidity was not eliminated, but lower than previously reported. The elevated risk of DRS was driven by diagnosis of asthma, which could in part be explained by misdiagnosis of persisting pulmonary toxicity.