Abstract P3-09-03: Single nucletotide polymorphisms of aromatase gene (CYP19A1) and toxicity of adjuvant aromatase inhibitors: A translational, prospective study

Background: Extending adjuvant endocrine treatment (ET) with aromatase inhibitors (AI) to 7-10 years decreases the risk of relapse in hormone receptor-positive (HR+) breast cancer (BC). However, such benefit comes at the price of higher incidence of skeletal and cardiovascular (CV) events. Biomarkers predicting such toxicities might help clinicians in tailoring adjuvant ET to patient’s needs. We conducted a prospective study to assess whether SNPs in the gene encoding for the aromatase enzyme (CYP19A1) affect the risk of skeletal and CV events in HR+ early BC patients enrolled in the GIM4 trial. Methods: The GIM4 trial randomized HR+ BC postmenopausal patients who had been already treated with 2-3 years of adjuvant tamoxifen to either 3-2 years or 5 years of adjuvant letrozole. Four SNPs of CYP19A1 were evaluated: rs10046, rs4646, rs479292 and rs727479. SNPs were genotyped through PCR on DNA obtained from patients’ peripheral blood samples. Skeletal and CV events were assessed from randomization in the GIM4 trial to last follow-up, disease recurrence or death. Skeletal events were defined as the onset of osteoporosis or bone fractures. CV events were defined as the onset of thrombosis, embolism, stroke, myocardial infarction, hearth failure, or arrythmia. Univariate and multivariate logistic regressions were performed to evaluate the association between SNPs and skeletal and CV events. Bonferroni correction for multiplicity was used for univariate SNPs association tests, with a corrected alpha of 0.012. Only associations with an alpha level Citation Format: Benedetta Conte, Chiara Molinelli, Giancarlo Bisagni, Antonio Durando, Giovanni Sanna, Stefania Gori, Ornella Garrone, Stefano Tamberi, Sabino De Placido, Francesco Schettini, Antonio Pazzola, Riccardo Ponzone, Filippo Montemurro, Gianluigi Lunardi, Rosario Notaro, Anna Turletti, Claudia Bighin, Francesca Poggio, Giulia Buzzatti, Matteo Lambertini, Luca Boni, Lucia Del Mastro. Single nucletotide polymorphisms of aromatase gene (CYP19A1) and toxicity of adjuvant aromatase inhibitors: A translational, prospective study [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 P3-09-03.