Risk of breast cancer according to clinicopathologic features among long-term survivors of Hodgkin's lymphoma treated with radiotherapy

BACKGROUND: It is unknown whether breast cancer (BC) characteristics among young women treated with radiotherapy (RT) for Hodgkin's lymphoma (HL) differ from sporadic BC. METHODS: Using population-based data, we calculated BC risk following HL according to clinicopathologic features. RESULTS: Compared with BC in the general population, risks of oestrogen receptor (ER)-positive/progesterone receptor (PR)-positive and ER-negative/PR-negative BC in young, irradiated HL survivors were increased five-fold (95% confidence interval (CI)=3.81-6.35) and nine-fold (95% CI=6.93-12.25), respectively. Among 15-year survivors, relative risk of ER-negative/PR-negative BC exceeded by two-fold (P=0.002) than that of ER-positive/PR-positive BC. CONCLUSION: Radiotherapy may disproportionately contribute to the development of BC with adverse prognostic features among young HL survivors.