Girls treated for Hodgkin’s lymphoma during adolescence acquire a considerable risk of developing breast cancer, as shown by an observational study. The study has an unusually long follow-up time, with an average of 17.8 years and a maximum of 33 years.
The study was published in Deutsches Ärzteblatt International (2014; 111[1-2]:3-9), and carried out by Günther Schellong, MD, of the Department of Pediatric Hematology and Oncology, University Hospital Münster, in Münster, Germany, and his colleagues in the German Working Group on the Long-Term Sequelae of Hodgkin’s Disease. The authors stated that part of their rationale for the study was to generate sufficient data for insurance companies to justify the screening of female patients who had received radiotherapy for Hodgkin lymphoma.
The incidence figures for secondary breast cancer are based on long-term observation of 590 female patients in the German-Austrian pediatric treatment trials dating back to the years 1978 to 1995. The authors estimate that 19% of the girls treated with radiotherapy for Hodgkin disease develop secondary breast cancer within 30 years as a result of that therapy. Because of these findings, a structured screening program for breast cancer in this high-risk group has been set up in Germany, making use of existing structures put in place by the German Consortium for Hereditary Breast and Ovarian Cancer (Deutsches Konsortium für familiären Brust- und Eierstockkrebs).
Among women age 25 to 45 years included in this study, the frequency of breast cancer was found to be 24 times higher than that in the corresponding normal population. In 25 of the 26 women affected by secondary breast cancer, the cancer occurred within the former radiation field. The authors wrote that location of the secondary cancer is an indicator of the causative effect of the radiation burden. The highest risk of secondary breast cancer was found in those who were treated with supradiaphragmatic radiotherapy when they were age 10 to 20 years—during puberty, when breast development rapidly occurs.
The study authors recommend that, when supradiaphragmatic radiotherapy is necessary in girls older than 9 years, the part(s) of the chest exposed to the radiation should be kept as minimal as medically justifiable. This will allow the risk of breast cancer to be kept as low as possible.