Role of Radiation Therapy in Hodgkin’s Lymphoma

Abstract

Radiation therapy was the first modality that solely cured patients with Hodgkin's lymphoma (HL) as early as the 1940s. In the absence of other curative options, the radiation field in full dose was extended to encompass both involved and uninvolved sites including many normal organs. Decades later, it was evident that some of the HL survivors succumbed to radiation-related effects, mostly second solid tumors. The more recent reliance on modern chemotherapy in combination with radiation yielded further improvement in disease control and allowed a marked reduction in radiation exposure. Some oncologists even suggested that chemotherapy alone might retain the excellent results obtained with combined modality and campaigned for the exclusion of radiotherapy from the treatment program. However, analysis of randomized studies (as discussed later) supports the inclusion of reduced-field and dose radiotherapy in treatment programs for HL. Furthermore, new concerns regarding the short- and long-term safety of enhancing chemotherapy to compensate for the omission of radiotherapy favor shorter courses of chemotherapy. Short chemotherapy supplemented with mini-radiotherapy constitutes a highly effective and safe treatment of HL, particularly in early stages.

Early-Stage Classic Hodgkin Lymphoma: The Utilization of Radiation Therapy and Its Impact on Overall Survival

“…[8-10, [15][16][17] Studies such as HD6 [12,18] may be unreliable to truly assess for OS as several deaths in the CMT arm were from unrelated causes. A more powerful meta-analysis of 1,245 patients demonstrated an OS benefit (HR=0.40) of CMT in early-stage HL.…”

“…[5,21] Fourth, this database does not include specific chemotherapy information regarding agents and number of cycles employed. To ensure that use of RT M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 15 represented consolidation treatment, we only included patients who underwent multi-agent chemotherapy regimens as standard practice at CoC-accredited centers.…”

Declining Use of Radiotherapy in Stage I and II Hodgkin’s Disease and Its Effect on Survival and Secondary Malignancies

“…Proponents of chemotherapy alone strategies believed an improved overall survival would be seen due to the reduction in late radiation related mortality. Furthermore, any increase in relapses seen in chemotherapy alone strategies would not affect survival because these patients could be salvaged with additional chemotherapy and stem-cell transplant (5). …”

Reduced versus full doses of irradiation after 3 cycles of combined doxorubicin, bleomycin, vinblastine, and dacarbazine in early stage Hodgkin lymphomas

“…The possibility cannot be excluded that such a highly significant difference in the incidence of complications (for such a small difference in the radiation dose) also may be caused in part by chance. However, recent retrospective studies have confirmed that, the lower the irradiation dose, the lower the incidence of secondary tumors and cardiac complications 23‐30. Because it was demonstrated recently that doses of 30 Gy were sufficient to sterilize lymphadenopathies that already had disappeared under chemotherapy,31‐33 it is plausible that, in patients with early HL who are in CR after a brief regimen of ABVD chemotherapy, irradiation doses of 25 Gy to 30 Gy limited to initially involved sites might be sufficient to maintain the high rate of FFTF observed in the current trial 32, 33…”