Patterns of relapse from a phase 3 Study of response-based therapy for intermediate-risk Hodgkin lymphoma (AHOD0031): a report from the Children's Oncology Group.

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.
Patients and Methods: From September 2002 to July 2010, 1712 patients <22 years old with stage I-IIA with bulk, I-IIAE, I-IIB, and IIIA-IVA with or without doxorubicin, bleomycin, vincristine, etoposide, prednisone, and cyclophosphamide 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). The SER patients were randomized to 2 additional ABVE-PC cycles or augmented chemotherapy with 21 Gy involved field radiation therapy (IFRT). RER patients were stipulated to undergo 2 additional ABVE-PC cycles and were then randomized to 21 Gy IFRT or no further treatment if complete response (CR) was achieved. RER without CR patients were non-randomly assigned to 21 Gy IFRT. Relapses were characterized without respect to site (initial, new, or both; and initial bulk or initial nonbulk), and involved field radiation therapy 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 experienced relapse, 198 of whom were fully evaluable for review. Those who progressed during treatment (n=30) or lacked relapse imaging (n=16) were excluded. The median time to relapse was 12.8 months. Of the 198 evaluable patients, 30% were RER/no CR, 26% were SER, 26% were RER/CR/no IFRT, 16% were RER/CR/IFRT, and 2% remained uncategorized. The 74% and 75% relapses involved initially bulky and nonbulky sites, respectively. First relapses rarely occurred at exclusively new or out-of-field sites. By contrast, relapses usually occurred at nodal sites of initial bulky and nonbulky disease.
Conclusion: Although response-based therapy has helped define treatment for selected RER patients, it has not improved outcome for SER patients or facilitated refinement of IFRT volumes or doses.
(Copyright © 2015 Elsevier Inc. All rights reserved.)