In:
Journal of Clinical Oncology, American Society of Clinical Oncology (ASCO), Vol. 38, No. 15_suppl ( 2020-05-20), p. 532-532
Abstract:
532 Background: Estimation of risk of recurrence is critical for adjuvant therapy decision making in patients with primary breast cancer. The POTENT trial examined outcomes associated with standard postoperative endocrine therapy with/without S-1 in patients with estrogen receptor (ER)-positive and human epidermal growth factor receptor 2 (HER2)-negative primary breast cancer (Toi et al, San Antonio Breast Cancer Symposium 2019). The aim of this study was to investigate absolute treatment effect across recurrence risk score to individualize indication for the concurrent administration of standard postoperative endocrine therapy with S-1. Methods: The POTENT trial included 1930 patients with ER-positive and HER2-negative breast cancer. The primary end point was invasive disease-free survival (iDFS). A continuous, composite measure of recurrence risk for each patient was determined from a Cox model incorporating age, tumor size, nodal status, grade, estrogen receptor, and Ki-67 expression levels. Absolute treatment effect of S-1 was estimated in each risk group defined by the composite risk score. Results: Of 1930 patients, we included the data from 1897 patients without unavailable data. Tumor grade, ER expression, and Ki-67 expression were available from central assessment. A Cox proportional hazards model for iDFS was estimated in standard endocrine therapy only group (N = 954). Age was excluded from the model because it did not add prognostic information. 5-year iDFS estimates were 91.6%, 82.0%, and 67.2% for low, intermediate, and high composite risk group, respectively. Absolute improvement in 5-year iDFS by the addition of S-1 to standard endocrine therapy were 0.9%, 6.7%, and 8.1% for low, intermediate, and high composite risk group, respectively. Hazard ratio for S-1 in each risk group were 0.86 (95%CI: 0.45-1.63, P = 0.642), 0.51 (95%CI: 0.34-0.78, P = 0.001), and 0.71 (95%CI: 0.49-1.02, P = 0.064), respectively. Continuous value of composite risk was also prognostic in a Cox proportional hazards model stratified by S-1 and neoadjuvant/adjuvant chemotherapy use (HR 2.58, 95%CI: 2.13-3.11, P 〈 0.0001). Conclusions: Patients with ER-positive and HER2-negative disease, and intermediate to high risk, defined by clinicopathological factors, experienced absolute improvement of about 7-8% in 5-year iDFS with addition of S-1 to standard endocrine therapy, while improvement was minimal in those at low risk. Clinical trial information: 000003969 .
Type of Medium:
Online Resource
ISSN:
0732-183X
,
1527-7755
DOI:
10.1200/JCO.2020.38.15_suppl.532
Language:
English
Publisher:
American Society of Clinical Oncology (ASCO)
Publication Date:
2020
detail.hit.zdb_id:
2005181-5
