Consolidative Proton Therapy Following High-dose Chemotherapy and Autologous Stem Cell Transplant in an Adolescent with Relapsed Hodgkin Lymphoma

Proton therapy for Hodgkin lymphoma

Hodgkin lymphoma has gone from an incurable disease to one for which the majority of patients will be cured. Combined chemotherapy and radiotherapy achieves the best disease control rates and results in many long-term survivors. As a result, a majority of long-term Hodgkin lymphoma survivors live to experience severe late treatment-related complications, especially cardiovascular disease and second malignancies. The focus of research and treatment for Hodgkin lymphoma is to maintain the current high rates of disease control while reducing treatment-related morbidity and mortality. Efforts to reduce late treatment complications focus on improvements in both systemic therapies and radiotherapy. Herein we review the basis for the benefits of proton therapy over conventional X-ray therapy. We review outcomes of Hodgkin lymphoma treated with proton therapy, and discuss the ability of protons to reduce radiation dose to organs at risk and the impact on the most significant late complications related to the treatment.

Involved-node proton therapy in combined modality therapy for Hodgkin lymphoma: results of a phase 2 study

PURPOSE

This study describes the early clinical outcomes of a prospective phase 2 study of consolidative involved-node proton therapy (INPT) as a component of combined-mode therapy in patients with stages I to III Hodgkin lymphoma (HL) with mediastinal involvement.

METHODS AND MATERIALS

Between September 2009 and June 2013, 15 patients with newly diagnosed HL received INPT after completing chemotherapy in an institutional review board-approved protocol comparing the dosimetric impact of PT with those of three-dimensional conformal radiation therapy (3DCRT) and intensity modulated RT. Based on (18)F-Fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) response, 5 children received 15 to 25.5 cobalt Gy equivalent (CGE) of INPT after receiving 4 cycles of Adriamycin, Bleomycin, Vincristine, Etoposide, Prednisone, Cyclophosphamide or Vincristine, adriamycin, methotrexate, Prednisone chemotherapy, and 10 adults received 30.6 to 39.6 CGE of INPT after 3 to 6 cycles of Adriamycin, Bleomycine, Vinblastine, Dacarbazine. Patients were routinely evaluated for toxicity during and after treatment, using Common Terminology Criteria for Adverse Events, version 3.0, and for relapse by physical examination and routine imaging. Relapse-free survival (RFS) and event-free survival (EFS) rates were calculated using the Kaplan-Meier method from the time of diagnosis.

RESULTS

The median follow-up was 37 months (range, 26-55). Two events occurred during follow-up: 1 relapse (inside and outside the targeted field) and 1 transformation into a primary mediastinal large B cell lymphoma. The 3-year RFS rate was 93%, and the 3-year EFS rate was 87%. No acute or late grade 3 nonhematologic toxicities were observed.

CONCLUSIONS

Although decades of follow-up will be needed to realize the likely benefit of PT in reducing the risk of radiation-induced late effects, PT following chemotherapy in patients with HL is well-tolerated, and disease outcomes were similar to those of conventional photon therapy.