Abstract Background: Women with a history of chest radiation for Hodgkin lymphoma are at an increased risk of developing breast cancer. Although mastectomy has historically been recommended for surgical treatment of breast cancers in women with prior radiation exposure, surgical management trends and contralateral breast cancer risk in this population remain undefined. Methods: We performed a population-based retrospective study using the Surveillance, Epidemiology, and End Results (SEER) database from 1990-2016. Our cohort included women who received radiation for Hodgkin lymphoma prior to 30 years old and were diagnosed with a subsequent breast cancer. We evaluated trends in local therapy including rates of breast conserving surgery (BCS) and mastectomy. In those undergoing unilateral surgery, the Kaplan-Meier method was used to estimate the 5- and 10-year cumulative incidence of contralateral breast cancer. Results: Our final cohort included 295 women with a median age of 22 years (range, 8-30 years) at Hodgkin lymphoma diagnosis, and 42 years (range, 22-65 years) at breast cancer diagnosis. Of these patients, 263 (89.2%) presented with unilateral breast cancer, while 32 (10.8%) presented with synchronous bilateral breast cancer. Overall, BCS was performed in 17.3% of patients and mastectomy was performed in 82.7%. In the 263 patients presenting with unilateral breast cancer, 50 (19.0%) underwent BCS and 213 (81.0%) underwent mastectomy. Subgroup analysis of mastectomy patients with surgical laterality information available demonstrated a 40.5% bilateral mastectomy rate. In the entire cohort, the 5-year incidence of contralateral breast cancer in women who underwent unilateral surgery was 9.4% (95% CI, 5.6-15.4), increasing to 20.2% (95% CI, 13.7-29.2) at 10-years of follow up. Hormone receptor status of the index breast cancer was not associated with significant differences in the incidence of contralateral breast cancer (p=0.13). Conclusions: Women with a history of prior chest radiation for Hodgkin Lymphoma with a diagnosis with breast cancer have a 10-year contralateral breast cancer risk of 20%. These findings support consideration of contralateral prophylactic mastectomy during surgical decision-making in this high-risk patient population. Citation Format: Elisheva R Eisenberg, Anna Weiss, Ipshita Prakash, Sonia Skamene, Mark Basik, Jean Francois Boileau, Lissa Ajjamada, Michael Pollak, Stephanie M Wong. Surgical management and contralateral breast cancer risk in women with a history of radiation therapy for Hodgkin lymphoma: Results from a population-based cohort [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr PD7-07.