Molecular Phenotypes of DCIS predict overall and invasive recurrence
Menée sur 314 patientes atteintes d'un carcinome canalaire in situ du sein (âge médian : 57,7 ans), cette étude met en évidence une association entre le sous-type moléculaire de la tumeur et le risque de récidive globale ou de récidive invasive
Background : Molecular phenotypes of invasive breast cancer predict early recurrence. DCIS exhibits similar phenotypes but their frequency and significance remain unclear. To determine whether DCIS molecular phenotypes predict recurrence, 314 women (median age 57.7 years) with primary DCIS who were screened or entered DCIS trials in a specialist breast unit from 1990-2010 were studied.
Patients and Methods : Ki67, ER, PR and HER2 expression within primary DCIS was established using immunohistochemistry (IHC). Patients were sub-divided into molecular phenotypes using IHC surrogates (Luminal A (ER/PR+HER2-), Luminal B (ER/PR+/HER2+), HER2-type (ERandPR-/HER2+) or triple negative (ER/PR/HER2)) and recurrence rates compared.
Results : Overall there were 57 recurrences (18.2%), 35 (11.2%) DCIS and 22 (7%) invasive cancer. A low rate of recurrence at five years was seen in Luminal A DCIS (7.6%) compared to 15.8-36.1% in other phenotypes. Independent predictors of overall recurrence on multivariate analysis were involved (<1mm) surgical margins (HR 4.31, P<0.001), high-grade lesions (HR 2.28, P<0.024) and molecular phenotype (HR 5.14, P=0.001 for Luminal B; HR 6.46, P<0.001 for HER2-type and HR 3.27, P=0.028 for triple negative disease compared to Luminal A DCIS). Independent predictors for invasive recurrence were high ki67 expression (HR 1.04, P=0.021) and molecular phenotype (HR 13.4 P=0.014 for Luminal B; HR 11.4, P=0.027 for HER2-type and HR 10.3, P=0.031 for triple negative compared to Luminal A DCIS.
Conclusions : DCIS molecular phenotype predicts for both overall and invasive recurrence. HER2 testing of DCIS could help clinicians individualise the treatment of patients with DCIS.
Annals of Oncology , résumé, 2015