Patients who experience a relapse after initial wide-field, high-dose radiation therapy have a good prognosis. Combination chemotherapy results in 10-year disease-free survival (DFS) and overall survival (OS) rates of 57% to 81% and 57% to 89%, respectively.[1,2,3,4] For patients who experience a relapse after initial combination chemotherapy, prognosis is determined more by the duration of the first remission than by the specific induction or salvage combination chemotherapy regimen. Patients whose initial remission after chemotherapy was longer than 1 year (late relapse) have long-term survival with salvage chemotherapy of 22% to 71%.[4,5,6,7,8,9] Patients whose initial remission after chemotherapy was shorter than 1 year (early relapse) do much worse and have long-term survival of 11% to 46%.[4,8,10]
Patients who relapse after initial combination chemotherapy usually undergo reinduction with the same or another chemotherapy regimen followed by high-dose chemotherapy and autologous bone marrow or peripheral stem cell or allogeneic bone marrow rescue.[11,12,13,14,15] This therapy has resulted in a 3- to 4-year DFS rate of 27% to 48%. Patients who are responsive to reinduction chemotherapy may have a better prognosis.
Two randomized trials have compared aggressive conventional chemotherapy versus high-dose chemotherapy with autologous hematopoietic stem cell transplantation for relapsed chemosensitive Hodgkin lymphoma (HL). Both trials show improvement in freedom from treatment failure at 3 years for the transplantation arm (75% vs. 45% and 55% vs. 34%, respectively); but no difference was observed in OS.[16,17][Level of evidence: 1iiDii]
In two retrospective reviews of patients who underwent autologous bone marrow transplantation (ABMT) for relapsed or refractory disease, a comparison was made of those who received involved-field radiation therapy (IF-XRT) for residual masses after high-dose therapy versus no further treatment.[18,19] Those who received IF-XRT had improved progression-free survival. Normalization of 18F-fluorodeoxyglucose–positron emission tomography–computed tomography (FDG-PET-CT) scans after reinduction therapy predicted a much better outcome after stem cell transplantation, with an event-free survival rate of 80% versus 29% in one phase II trial.[Level of evidence: 3iiiDi] For patients at high risk of residual HL after stem cell transplant, a phase III study (the AETHERA trial [NCT01100502]) is evaluating the role of brentuximab vedotin.