Changes in the use of radiation therapy for early classical Hodgkin lymphoma in adolescents and young adults: implications for survival and second malignancies.

Omission of radiation therapy (RT) in adolescents and young adults (AYA) with early classical Hodgkin lymphoma (cHL) may affect survival and risk of second malignancies (SMN). Using the Surveillance, Epidemiology and End Results database we found reduction in RT use from 60.8% among 2614 cases from 1995 to 2002 to 52.9% among 2542 cases from 2003 to 2010, p<0.001. Survival at 5 years with and without RT was 95.1% vs. 93.3%, p=0.013 for 1995-2002 and 97.7% vs. 96.4%, p=0.021 for 2003-2010. Omission of RT was affected by 2003-2010 era, race-ethnicity, income and education and independently increased the risk of death (hazard ratio 1.34, p=0.011). The cumulative risk of SMN at 150 months was 3.3% vs. 3.0% (p=0.87) while the risk of death without SMN (competing risk) was 5.7% vs. 8.8% for RT and no-RT patients, respectively (p=0.0009). Omission of RT for early cHL in AYA may increase mortality without reduction in SMN.