Breast Cancer Index Identifies Early Stage ER+ Breast Cancer Patients at Risk for Early and Late Distant Recurrence
A partir de l'analyse rétrospective d'échantillons tumoraux prélevés sur 317 patientes atteintes d'un cancer du sein traité par tamoxifène et sur 358 autres patientes incluses dans une cohorte multicentrique, cette étude montre que l'indice BCI (Breast Cancer Index), basé sur l'expression de plusieurs gènes, permet d'évaluer le risque de récidive distante à court ou long terme (> 5 ans) chez les patientes atteintes d'un cancer du sein ER+ de stade précoce
Purpose : Residual risk of relapse remains a substantial concern for hormone-receptor (HR+) positive breast cancer patients, with approximately half of all disease recurrences occurring after 5 years of adjuvant anti-estrogen therapy.
Experimental Design : The objective of this study was to examine the prognostic performance of an optimized model of Breast Cancer Index (BCI), an algorithmic gene expression-based signature, for prediction of early (0-5 years) and late (>5 years) risk of distant recurrence in estrogen receptor positive (ER+), lymph node negative (LN-) patients. The BCI model was validated by retrospective analyses of tumor samples from tamoxifen-treated patients from a randomized prospective trial (Stockholm TAM, n=317) and a Multi-institutional cohort (n=358).
Results : Within the Stockholm TAM cohort, BCI risk groups stratified the majority (~65%) of patients as low risk with <3% distant recurrence rate for 0-5 years and 5-10 years. In the Multi-institutional cohort, which had larger tumors, 55% of patients were classified as BCI low risk with <5% distant recurrence rate for 0-5 years and 5-10 years. For both cohorts, continuous BCI was the most significant prognostic factor beyond standard clinicopathological factors for 0-5 years and >5 years.
Conclusions : The prognostic sustainability of BCI to assess early and late distant recurrence risk at diagnosis has clinical utility for decisions of chemotherapy at diagnosis and for decisions for extended adjuvant endocrine therapy beyond 5 years.
Clinical Cancer Research , résumé, 2013