External beam radiation therapy (RT) is the standard treatment for stage I-II, grade 1-2 follicular lymphoma. Because of an indolent natural history, some advocate alternative management strategies, including watchful waiting for this disease. The relative improvement in outcomes for patients treated with and without RT has never been tested in randomized trials.
The Surveillance, Epidemiology, and End Results database was queried for adult patients with stage I-II, grade 1-2 follicular lymphoma diagnosed from 1973 to 2004. Retrievable patient data included age, sex, race, stage, extranodal disease, and treatment with RT within the first year after diagnosis. Actuarial overall survival (OS) and disease-specific survival (DSS) were analyzed.
A total of 6568 patients were identified. DSS at 5, 10, 15, and 20 years in the RT group was 90%, 79%, 68%, and 63% versus 81%, 66%, 57%, and 51% in the no RT group (hazard ratio [HR], 0.61; 95% confidence interval [CI], 0.55-0.68; P < .0001). OS at 5, 10, 15, and 20 years in the RT group was 81%, 62%, 45%, and 35% versus 71%, 48%, 34%, and 23% in patients not receiving RT (HR, 0.68; 95% CI, 0.63-0.73; P < .0001). On multivariate analysis, upfront RT remained independently associated with improved DSS (P < .0001, Cox HR, 0.65; 95% CI, 0.57-0.72) and OS (P < .0001; Cox HR, 0.73; 95% CI, 0.67-0.79). Lymphoma was the most common cause of death (52%). Only 34% of patients received upfront RT.
Upfront RT was associated with improved DSS and OS compared with alternate management approaches, a benefit that persisted over time. This benefit suggests that watchful waiting with administration of salvage therapies on progression/relapse do not compensate for inadequate initial definitive treatment. Although it is the standard of care for this disease, RT for early stage low-grade follicular lymphoma is greatly underused in the US population; increased use of upfront RT could prevent thousands of deaths from lymphoma in these patients. Cancer 2010. © 2010 American Cancer Society.