Treatment response and 5-year distant metastasis-free survival outcome in breast cancer patients after the use of MammaPrint and BluePrint to guide preoperative systemic treatment decisions

Abstract

AimIn the prospective neoadjuvant NBREaST II study, we measured the response to preoperative treatment and 5-year survival outcome in the molecular subgroups as determined by combining the MammaPrint and BluePrint. MethodsBetween 2012 and 2016 we included 256 patients for whom MammaPrint and BluePrint were performed on pre-treatment core needle biopsies. The primary objective of the NBREaST II trial was to measure chemosensitivity or endocrine sensitivity in the molecular subgroups. Distant metastasis-free survival (DMFS), relapse-free survival (RFS) and breast cancer-specific survival (BCSS) were the endpoints for long-term follow-up. ResultsMammaPrint and BluePrint molecular sub-typing reclassified 9% (24/256) of tumours, reassigning more responsive patients to the HER2-Type and Basal-Type, and less responsive patients to the Luminal-Type category. Patients with Luminal A-Type tumours (n = 67, 26% of the total cohort) had a poor response when treated with neoadjuvant chemotherapy (NCT), but had the highest 5-year DMFS outcome (91.4%; 95% CI 78.6–96.7) of all molecular subgroups. Out of the IHC/FISH defined HER2+ tumours (n = 41), 37% were not classified as HER2-Type by BluePrint. Notably, in BluePrint HER2-Type tumours, we observed a higher pCR rate, whereas the 5-year DMFS was lower compared to IHC/FISH-defined HER2+ tumours. The pCR rate and 5-year outcome for patients with Basal-Type tumours were similar to IHC/FISH-defined TN tumours. ConclusionThese findings suggest that MammaPrint and BluePrint can predict chemosensitivity and 5-year outcomes more accurately compared to traditional pathological sub-typing, supporting informed decision-making.