SAN DIEGO – Patients with stage I and II Hodgkin’s disease who received radiation therapy as part of their treatment plan in 1988-2006 had an 11% improvement in overall survival at 5 years, compared with patients who did not receive radiation, results from large analysis demonstrated.
Use of radiation for this patient population decreased by nearly 20% over the same time period, however, while the percentage of patients who developed second malignancies did not differ between those who had radiation and those who did not, Dr. Matthew Koshy reported at the annual meeting of the American Society for Radiation Oncology.
Dr. Matthew Koshy
In the early 1990s, several publications revealed significant long-term complications associated with a combined-modality approach involving full-dose chemotherapy and extended-field radiation therapy in patients with early-stage Hodgkin’s disease, said Dr. Koshy, who led the study during his residency in the department of radiation oncology at the University of Maryland Medical Center, Baltimore.
"As a result, cooperative groups changed the treatment paradigm," said Dr. Koshy, currently of the department of radiation and cellular oncology at the University of Chicago. "The goal of any treatment strategy in Hodgkin’s disease is to maintain the excellent survival rates while reducing the morbidity by minimizing radiotherapy and chemotherapy. As a result, two treatment strategies emerged: One was the use of combined-modality therapy, but with a reduction in the irradiated volume, the radiation dose, the number of chemotherapy cycles, and the number of chemotherapy agents. A second treatment strategy was to use chemotherapy alone with additional cycles and eliminate radiation from the treatment paradigm."
In an effort to study the use of radiation therapy for patients with early-stage Hodgkin’s disease and its impact on overall survival and secondary malignancies, Dr. Koshy and his associates analyzed data from the SEER (Surveillance, Epidemiology, and End Results) database of the National Cancer Institute for patients aged 20 years and older who were diagnosed with stage I or II Hodgkin’s disease in 1988-2006. SEER covers 26% of the U.S. population and collects incidence and survival data from 17 population-based registries.
Of the 12,467 patients studied, Dr. Koshy reported that 51.5% received radiation therapy. The median follow-up was 4.9 years, and 21% of the cohort had more than 10 years of follow-up. Factors associated with a higher likelihood of receiving radiation therapy were having stage II disease, extranodal involvement, B-symptoms (fever greater than 38??C, drenching sweats, weight loss greater than 10% of body weight) and lymphocyte-rich or nodular sclerosis histology.
The 5-year overall survival was 87% for patients who received radiation therapy, compared with 76% for those who did not (P less than .0001).
To control for selection bias, Dr. Koshy and his associates examined patients who survived a minimum of 1 year. The 5-year overall survival for this subset of patients was 90% for patients who received radiation therapy, compared with 85% for those who did not (P less than .001).
In addition, the 5-year, cause-specific survival among all patients in the analysis was 94% for those who received radiation therapy, compared with 88% for those who did not (P less than .0001).
The actuarial rate of developing a second malignancy was statistically similar between the two groups: 14.6% for patients who received radiation therapy, compared with 15% for those who did not. Dr. Koshy acknowledged certain limitations of the study, including the fact that there was no information about whether chemotherapy was administered to these patients or not, or about the mode of radiation delivery.
Some recently published phase III studies have examined the withholding of radiation therapy from patients with early-stage Hodgkin’s disease, Dr. Koshy said, "and all have shown an improvement in freedom from progression in patients who have received radiation therapy. There has never been a phase III study that has validated a chemotherapy-alone strategy."
Despite this fact, he and his associates observed a nearly 20% decrease in the use of radiation therapy for these patients between 1988 and 2006 (from 62.9% to 43.7%). "This large decrease may be a result of patients not receiving centralized care in a multidisciplinary setting," Dr. Koshy said in a later interview. "It is paramount that all cases of early-stage Hodgkin’s lymphoma be considered for combined modality therapy. Treatment planning involving radiation oncologists and medical oncologists should be standard of care."
Dr. Koshy said that he had no relevant financial conflicts to disclose.