What is the prognosis for patients who relapse after primary radiation therapy for early-stage low-grade follicular lymphoma?

PURPOSE: To investigate the potential for long-term survival for patients who relapsed after primary radiation therapy (RT) for early-stage low-grade follicular lymphoma and to assess the relative importance of prognostic factors.

METHODS AND MATERIALS: Records were reviewed for 79 patients with stage I (n = 32) and II (n = 47) follicular small cleaved cell (fsc, n = 48) and follicular mixed small cleaved cell and large-cell (fmx, n = 31) lymphoma who relapsed after radical RT at Stanford University. Most patients had received doses of 35 to 45 Gy to involved (n = 30) or extended fields (n = 39) or total/subtotal lymphoid irradiation (n = 9).

RESULTS: Median time to relapse was 2 years. Most relapses were detected on history (30%) or physical examination (66%). Positive relapse investigations included lymphangiogram (n = 19), chest radiograph (n = 5), and bone marrow biopsy (n = 6). Known extent of relapsed disease was: stage I, n = 30; stage II, n = 26; stage III, n = 10; and stage IV, n = 8. Patients were managed with "watchful waiting" (37%), further RT (39%), chemotherapy [CT, (17%)], or RT + CT (5%). Actuarial survival rates after relapse at 5, 10, 15, and 20 years were 56%, 35%, 17%, and 17% respectively. Median survival was 5.3 years after relapse. Median survival for relapse stage I, II, III, and IV was 10.2, 5.5, 3.0, and 1.1 years respectively. Progression-free survival rates at 5, 10, 15, and 20 years after relapse were 44%, 22%, 22%, and 22% respectively. Factors associated with reduced survival were increasing age, increasing relapse stage, symptoms, histologic transformation and > or = 3 relapse sites. Survival was the same for initial management with "watchful waiting" or RT.

CONCLUSION: Approximately 20% of patients experienced prolonged survival after relapse. Younger, asymptomatic patients with stage I-II relapsed disease had the best outcome but results were inferior to those for newly diagnosed stage I-II disease.