Estrogen Receptor Status of Contralateral Breast Cancers—Value Added or Pathology Without a Purpose?

Menée auprès de témoins et de 1 290 patientes atteintes d'un cancer du sein diagnostiqué sur la période 1985-2000 (âge médian au diagnostic : 47 ans), cette étude analyse le risque de cancer controlatéral associé aux variants constitutionnels de gènes de susceptibilité au cancer sein en fonction du statut des récepteurs à oestrogènes

Résumé en anglais

Pathologic characteristics of invasive breast cancers associated with pathogenic germline variants (PGV) in breast cancer susceptibility genes have been described. More recently, quantitative estimates of contralateral breast cancer (CBC) risk among carriers have also been reported that leverage large datasets, such as those from CARRIERS (Cancer Risk Estimates Related to Susceptibility) and BRIDGES (Breast Cancer Risk After Diagnostic Gene Sequencing). These data are now regularly incorporated into clinical discussions with patients who have PGV in breast cancer susceptibility genes; they impact shared decision-making surrounding medical and surgical approaches in affected and unaffected individuals. The report by Reiner and colleagues builds upon these studies by leveraging the Women’s Environment, Cancer, and Radiation Epidemiology (WECARE) population-based database to evaluate ER-specific CBC risks in those with BRCA1, BRCA2, ATM, and CHEK2 1100delC PGV. Cases had CBC with known ER status diagnosed at least 1 year after the first invasive breast cancer, and matched controls had a diagnosis of unilateral invasive breast cancer prior to the age 55 years without development of CBC despite an intact contralateral breast. Despite the substantial study population size overall, as the authors point out, this study included a small number of variant carriers (148 PGV carriers, many of whom were BRCA1 or BRCA2 carriers, among 1290 study participants, with too few PALB2 carriers to evaluate this gene). The authors found that the rate of ER-positive CBC was 5 to 6 times higher in women with PGV in BRCA2, ATM, and CHEK2, and that the rate of ER-negative CBC was 26 times higher in women with BRCA1 PGV, as compared with those without PGVs in the respective genes. ER status of the first primary breast cancer did not significantly modify these associations.