Purpose
The study was designed to determine whether response-based therapy improves outcomes in intermediate-risk Hodgkin lymphoma. We examined patterns of first relapse in the study.
Methods
From 9/02 – 7/10, 1712 patients <22 yrs of age with stage I–IIA with bulk, I–IIAE, I–IIB, and IIIA–IVA with/without bulk were enrolled. Patients were categorized as rapid (RER) or slow early responders (SER) after 2 cycles of doxorubicin, bleomycin, vincristine, etoposide, prednisone, and cyclophosphamide (ABVE-PC). SER patients were randomized to 2 additional ABVE-PC cycles or augmented chemotherapy with 21Gy IFRT. RER patients were stipulated to undergo 2 additional ABVEPC cycles and were then randomized to 21Gy IFRT or no further treatment if complete response (CR) was achieved. RER without CR patients were non-randomly assigned to 21Gy IFRT. Relapses were characterized with respect to site (initial, new or both; and initial bulk or initial non-bulk), and IFRT field (in-field, out-of-field, or both). Patients were grouped by treatment assignment (SER; RER/no CR; RER/CR/IFRT; and RER/CR/no IFRT). Summary statistics were reported.
Results
At 4-year median follow-up, 244 patients had relapsed, 198 of whom were fully evaluable for review. Those who progressed on treatment (n=30) or lacked relapse imaging (n=16) were excluded. Median time to relapse was 12.8 months. Of the 198 patients, 30% were RER/no CR, 26% were SER, 26% were RER/CR/no IFRT, 16% were RER/CR/IFRT, and 2% remained uncategorized. 74% and 75% relapses involve initially bulky and non-bulky sites, respectively. First relapses rarely occurred at exclusively new or out-of-field sites. In contrast, relapses usually occurred at nodal sites of initial bulky and non-bulky disease.
Conclusion
While response-based therapy has helped define treatment for select RER patients, it has not improved outcome for SER patients or facilitated refinement of IFRT volumes or doses.