Publication: Annals of Surgical Oncology, Sept 1, 2023
Peter Blumencranz MD, FACS, Mehran Habibi MD, Steve Shivers PhD, Geza Acs MD, Lisa E. Blumencranz PhD, Erin B. Yoder MS, Bastiaan van der Baan MS, Andrea R. Menicucci PhD, Patricia Dauer PhD, William Audeh MD & Charles E. Cox MD
Neoadjuvant chemotherapy (NCT) increases the feasibility of surgical resection by downstaging large primary breast tumors and nodal involvement, which may result in surgical de-escalation and improved outcomes. This subanalysis from the Multi-Institutional Neo-adjuvant Therapy MammaPrint Project I (MINT) trial evaluated the association between MammaPrint and BluePrint with nodal downstaging.
Patients & Methods
The prospective MINT trial (NCT01501487) enrolled 387 patients between 2011 and 2016 aged ≥ 18 years with invasive breast cancer (T2–T4). This subanalysis includes 146 patients with stage II–III, lymph node positive, who received NCT. MammaPrint stratifies tumors as having a Low Risk or High Risk of distant metastasis. Together with MammaPrint, BluePrint genomically (g) categorizes tumors as gLuminal A, gLuminal B, gHER2, or gBasal.
Overall, 45.2% (n = 66/146) of patients had complete nodal downstaging, of whom 60.6% (n = 40/66) achieved a pathologic complete response. MammaPrint and combined MammaPrint and BluePrint were significantly associated with nodal downstaging (p = 0.007 and p < 0.001, respectively). A greater proportion of patients with MammaPrint High Risk tumors had nodal downstaging compared with Low Risk (p = 0.007). When classified with MammaPrint and BluePrint, more patients with gLuminal B, gHER2, and gBasal tumors had nodal downstaging compared with HR+HER2−, gLuminal A tumors (p = 0.538, p < 0.001, and p = 0.013, respectively).
Patients with genomically High Risk tumors, defined by MammaPrint with or without BluePrint, respond better to NCT and have a higher likelihood of nodal downstaging compared with patients with gLuminal A tumors. These genomic signatures can be used to select node-positive patients who are more likely to have nodal downstaging and avoid invasive surgical procedures.