Gene expression profiling for breast cancer in the Philippines: Real-world data on feasibility, possible disparities, and clinical implications for LMICs.

Abstract

e12569 Background: Racial, biological and socioeconomic disparities have most recently been shown to impact on specific molecular subtypes of breast tumorsand on its clinical implications including the decision to omit adjuvant chemotherapy. Despite considerable logistical and cost constraints, we provide the first-ever documented and tangible profile of gene expression of breast cancers in the Philippines for a better understanding of its role in facilitating future testing and health policy making in an LMIC setting. Methods: This is a case series review of the 70-gene (MammaPrint) and 80-gene (BluePrint) signature done among Filipino patients from Dec 2013 to Nov 2021. Data on demographics, tumor characteristics, adjuvant therapy received and clinical risk assessment in the MINDACT study to c-low or c-high were gathered and analyzed. Results: Thirty-six females aged 36-75 years with invasive breast carcinoma Stage I to IIB had the following profile: Low Risk Luminal A (19, 52.8%), High Risk Luminal B (7, 19.4%), High Risk Her-2 (3, 8.3%), High Risk Basal (7, 19.4%). All low-risk patients underwent adjuvant endocrine therapy alone thus foregoing otherwise clinically recommended chemotherapy. No significant trend (in age, laterality, tumor grade and stage) can be discerned within all stratification groups except in the following areas: Histology: low risk profile in lobular carcinoma (n=2) Tumor Size: high risk profile in all tumors measuring 4.1 – 5 cms (n=4) Nodal Status: low risk profile in 6 of 8 patients with node+ disease LVI among node- patients: low risk profile in all 6 LVI+ tumors HR status: high risk profile in all 7 tumors with HR- status Her-2 neu status: good IHC test correlation with genomic subtype HR and Her-2 neu status: HR+her2- status in all 19 low risk tumors while high risk basal subtype in all 5 HR-her2- or triple-negative (TNBC) tumors Clinical risk in MINDACT: low genomic risk in 11 of 25 (44%) c-high patients. Conclusions: Gene profiling of breast cancer in a resource-limited setting is feasible and imperative to avoid chemotherapy and/or overtreatment. Clinically relevant disparities may exist which in turn can affect outcomes, decisions and health policies in adjuvant therapy and overall cancer care.[Table: see text]