Abstract P3-08-17: Clinical factors of late recurrence of HR+ early breast cancer after completion of 5 years of aromatase inhibitor and development of a prognostic tool. A study of 1496 women of the ICO database
Authors: Frenel Jean-Sebastien , Campion Loïc , Robert Marie , Jean-Marc Classe , Mario Campone , Moreau-Bachelard Camille 
Published: March 2020

Abstract
INTRODUCTION: Post-menopausal women with hormone receptor positive (HR+) early breast cancer receive generally 5 years of adjuvant aromatase inhibitor (AI). However, more than half of recurrences occur after that period and the identification of patients who could derive benefit from the prolongation of AI above 5 years is a critical task. We aimed to develop a simple prognostic tool to estimate the risk of late recurrence of patients with HR+ EBC who had completed 5 years of AI, in order to help the decision making process of extending AI. METHODS: We conducted a monocentric, retrospective study based on a local database (BERENIS), which included all patients treated for EBC at the Institut de Cancerologie de L’Ouest (ICO). We identified all post-menopausal women diagnosed with HR+ EBC and who had completed at least 54 months of adjuvant AI. We analysed the outcome after stopping AI, including HR+ metastatic, contralateral and ipsilateral relapses. RESULTS: Between January 2003 and December 2011, 1107 post-menopausal women were retrieved. Median follow-up after completion of 5y AI was 32.6 months [1-132]. The recurrence rate of HR+ disease was 8% (n=89) including 60 metastatic relapses, and 8 and 21 ipsilateral and contralateral local relapses respectively. Multivariate analysis showed that the pathological tumour size (continuous variable) (HR = 1.02; p = 0.035), the number of macro-metastases (continuous variable) (HR = 1.17; p = 0.001) and age (HR = 1.04; p = 0.012) were independent factors of HR+ invasive disease free survival. We then designed a score estimating the risk of late relapse. This was designed as follow: 10*(tumour size (mm)) +79*(number of macro metastases) +14*(years old). Patients were classified as low risk (78.8% of patients) or high risk (21.2%) with a threshold at 1200 points. Low risk patients had a mean 5- to 10-year risk of invasive HR+ local or distant recurrence of 9.8% (95% CI, 7.1% to 13.5%) as compared with 38.3% (95% CI, 27.6% to 50.9%) for high-risk groups. CONCLUSION: Our study is one of the first estimating the risk of late relapse in a population of post-menopausal women who have completed 5y of adjuvant AI for EBC. Our simple score identify accurately patients at high risk of relapse despite 5 years of treatment. This tool may help oncologist to select patients who could derive the most benefit of extending adjuvant AI above 5 years. A validation of this score in an independent population is necessary.
Citation Format: Jean-Sebastien Frenel, Loïc Campion, Marie Robert, Classe Jean-Marc, Campone Mario, Camille Moreau-Bachelard. Clinical factors of late recurrence of HR+ early breast cancer after completion of 5 years of aromatase inhibitor and development of a prognostic tool. A study of 1496 women of the ICO database [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P3-08-17.