ESTRO 2023 - Abstract Book

S527

Sunday 14 May 2023

ESTRO 2023

Conclusion This report provides a European-wide standard in HDR-PDR BT source calibration at the hospital level to maintain high quality patient treatments.

Mini-Oral: Radiotherapy and the heart

MO-0637 Risk of myocardial infarction/stroke after breast cancer treatment: a cohort of 1.3 million patients P. Franco 1 , E. Favaro 2 , G.W. Gilcrease 3 , S.C. Calabrese 4 , E. Ferracin 5 , D. Di Cuonzo 6 , A. Macciotta 7 , A. Catalano 8 , L. Dansero 8 , A. D'Errico 9 , G. Numico 10 , R. Gnavi 11 , G. Costa 8 , E. Pagano 6 , C. Sacerdote 6 , F. Ricceri 8 1 University of Eastern Piedmont, Department of Translational Sciences, Novara, Italy; 2 Department of Medical Sciences, University of Turin, Turin, Italy; 3 UNESCO, Chair in Sustainable Development and Territory Management, Turin, Italy; 4 University of Turin, University of Turin, Turin, Italy; 5 ASL TO3, Unit of Epidemiology, Regional Health Service, Grugliasco, Italy; 6 University of Turin, School of Medicine and Surgery, Turin, Italy; 7 Department of Clinical and Biological Sciences, University of Turin, Centre for Biostatistics, Epidemiology, and Public Health (C-BEPH), Turin, Italy; 8 Centre for Biostatistics, Epidemiology, and Public Health (C-BEPH), Department of Clinical and Biological Sciences, University of Turin, Turin, Italy; 9 ASL TO3, Grugliasco , Unit of Epidemiology, Regional Health Service, Turin, Italy; 10 “Santa Croce e Carle” Hospital and Regional Oncology Network, Department of Medical Oncology, Cuneo, Italy; 11 ASL TO3, Grugliasco , Unit of Epidemiology, Regional Health Service, Grugliasco, Italy Purpose or Objective Due to effective screening programs and cancer therapies, the number of long-term survivors after breast cancer (BC) has increased. However, these women have a higher risk of second primary cancer, cardiovascular, and metabolic diseases. To assess the risk of myocardial infarction (MI) and stroke in female BC patients after treatment, we analysed administrative data of a cohort of > 4 million inhabitants of the XXXX region, Italy. Materials and Methods Women under study belong to the XXX Longitudinal Study (PLS), an administrative longitudinal cohort linked with the 2011 census data and followed-up through administrative record-linkage for mortality, hospital admissions, drug prescriptions, and specialist examinations. We identified all incident BC patients in XXXX between 2011 and 2017 (exposure) and incident cases of MI and stroke (outcomes), using 2 validated algorithms. Treatment received (chemotherapy-CT; radiation therapy- RT; endocrine therapy-HT) was also identified. The effect of BC on the risk of MI and stroke was tested using different Cox models to account for competing risks. BC women were compared with healthy women. Women who underwent a specific therapy were compared both with healthy women and other BC patients. To consider possible confounders, we adjusted the models for hypertension, hypercholesterolemia, diabetes, education, and with chronic obstructive pulmonary disease (as proxy of heavy smoking). Results We included 1,342,333 women aged 30 to 75 years observing 19,203 women with BC diagnosis. A total of 13,492 patients received RT, 7,824 received CT (1,992 CT only and 5,832 both RT and CT). A total of 14,767 women were treated with aromatase inhibitors and 10,752 with tamoxifen. Women with BC showed an increased risk for both MI and stroke compared to women without BC. In the fully adjusted model, women with BC showed an increased risk for MI (HR:1.20;95%CI:1.05- 1.38) and for stroke (HR:1.58;95%CI:1.38-1.82). Women with BC treated with CT only had double the risk of MI compared to women without BC (HR: 2.60;95%CI:1.89-3.60) and compared to women with BC treated with surgery (HR:2.65;95%CI: 1.64-4.28). Women with BC treated with only RT did not show a statistically significance higher risk compared to women without BC and compared to women with BC treated with surgery. The results showed that the risk of stroke was independent from specific treatments. Women with BC treated with aromatase inhibitors or tamoxifen did not show an increased risk of MI, but a significant increase of stroke was observed for those treated with aromatase inhibitors (HR:1.25;95%CI 1.34-1.87). (Table.1)