Radiation Therapy Improves Survival in Hodgkin's Lymphoma

Despite a recent decline in utilization, consolidated radiation therapy (RT) has been shown to improve 10-year survival rates for patients with stage I/II Hodgkin's lymphoma following treatment with chemotherapy, according to data from a large analysis presented at the ASTRO 56th Annual Meeting.

The use of RT for patients with early-stage Hodgkin's lymphoma has decreased from 56% to 41% between 1998 and 2011. In 88.4% of the patients, the physician-reported reason for not administering RT was that it was not part of the planned initial treatment strategy. Based on the results of the analysis, the authors of the study suggested that since combined modality therapy contributed significantly to the cure rate for patients with early stage Hodgkin's lymphoma, RT should remain standard practice.

“Multiple prospective, randomized trials have shown a significant improvement in disease control with the addition of RT, however previous trials were limited by low patient numbers and limited follow-up and thus, were unable to demonstrate an overall survival benefit,” lead study author Rahul R. Parikh, MD, a radiation oncologist at Mount Sinai Beth Israel and an Assistant Professor of Radiation Oncology at Icahn School of Medicine at Mount Sinai, said in a statement. “This is the largest dataset in this patient population to demonstrate a survival benefit with the addition of RT.”

For the study, 41,502 patients with an average age of 37 who had been diagnosed with stage I and II Hodgkin’s lymphoma between 1998 and 2011 were selected from National Cancer Data Base. The median follow-up for patients in the database was 7.5 years. Of the patients selected, 96% (n= 39,842) had received multi-agent chemotherapy and 49% (n= 20,441) had received RT at a median dose of 30.6 Gy.

The association between RT use, co-variables, and outcome was assessed in a multivariate Cox proportional hazards model. Survival was estimated using the Kaplan-Meier method.

The 10-year overall survival (OS) rate for the entire group of patients was 80.8%. After a median of 10 years, the OS rate for patients who received RT was 84.4% compared with 76.4% for those who did not (HR = 0.51; 95% CI, 0.46-0.56, P <.00001).

The omission of RT was associated with higher rates of transplant procedures performed, a surrogate for persistent/relapsed disease (P=.04). Additionally, initiating chemotherapy within 30 days after diagnosis was associated with improved OS at 10 years (84.5% vs 78.3%, P <.00001), even when adjusting for all co-variables (HR = 0.86; 95% CI 0.77-0.95, P = .005).

The research also indicated that RT use was associated with younger patients (≤40 years), who had a higher socioeconomic status, who had access to health insurance, and who received treatment at comprehensive cancer centers (P <.0001).

“Given that the utilization of RT was associated with younger age, insurance status, higher socioeconomic status, and treatment at comprehensive cancer centers, we have highlighted ongoing disparities in Hodgkin’s Disease treatment and it is important that we recognize these findings as potential barriers to care,” Parikh said. “Given the survival benefit demonstrated in this study, radiotherapy should be included in the combined modality approach of multi-agent chemotherapy followed by consolidation RT in order to maintain high overall survival rates for this curable disease.”

The adverse events associated with the addition of radiation therapy were not noted in the analysis. Short-term side effects of RT generally include skin reaction, fatigue, nausea, and diarrhea.

In general, long-term adverse events represent a leading concern facing the administration of RT for patients with early-stage Hodgkin's lymphoma. These side effects usually do not manifest for 10 to 20 years following treatment. While newer approaches for administering RT hope to ameliorate these concerns, further data are still required to analyze this risk.

Parikh RR, Yahalom J, Talcott JA, et al. Early-Stage Hodgkin's Disease: The Utilization of Radiation Therapy and Its Impact on Overall Survival. Presented at: 2014 ASTRO Annual Meeting; September 14 - 17, 2014; San Francisco, CA. Presentation Number: CT-08

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