A. Armengol-Alonso (CDMX, Mexico)
Instituto Nacional de Ciencias Medicas y Nutricion Salvador ZubiranAuthor Of 1 Presentation
39P - Applicability of a pathology-based combined model NOLUS (NOn-LUminal Score) in HR+/HER2- early breast cancer patients treated at a tertiary referral center in México
Abstract
Background
In Mexico, breast cancer (BC) is the leading cause of cancer death in women over 25 years old. Access to genomic platforms for biological intrinsic subgroups identification is not covered by the public health system. Within early BC (EBC) RH+/HER2- the non-luminal subgroup is associated with poor oncologic outcomes.
Methods
A retrospective review of 580 consecutive records of a BC prospective cohort attendeding INCMNSZ during the period Jan-2011 to Jun-2019. A combined score based on ER, PR and Ki67 levels was calculated. NOLUS formula was derived: −0.45∗ER −0.28∗PR +0.27∗Ki67 + 73.02. High-NOLUS cutoff point ≥ 51.38 identified non-luminal population and low NOLUS < 51.38. The model was tested in EBC to identify the frequency of the non-luminal subtype.
Results
Luminal subtype 65.9%, triple negative 17.7%, HER2+ 16.4%. St Gallen classification: luminal A 58.3%, luminal B 33.8%, luminal B HER2+ 7.9%, Within the RH+/HER2- subgroup (n 175) low-NOLUS was 90.3%, and high-NOLUS 9.7%. Tumor grade was G1 37.7%, G2 49.7%, G3 12.6%. 63.9% of the patients with low-NOLUS had luminal A and 36.1% were luminal B. 5.9% of patients with high-NOLUS had luminal A vs 94.1% luminal B (p=<0.001). 82.3% received surgical treatment as initial strategy, neoadjuvant (n 31) 17.7%, (22 chemotherapy, 9 endocrine therapy). None of the patients presented pathologic complete response. Chemotherapy was received in 54.9%, endocrine therapy 95.4%. Median follow-up was 35.5 months, disease-free survival (DFS) of the entire cohort was 95.4% and cancer-specific survival (CSS) 97.1%. Relapse occurred in 4.6% (8/175). Distant recurrence (DR) in 7, all in the high-NOLUS group. DFS for low-NOLUS was 98.1% vs 70.6% high-NOLUS (p=<0.005). CSS for low-NOLUS was 98.1% vs high-NOLUS 88.2% (p=<0.044).
Conclusions
The frequency of the non-luminal subgroup in Mexican patients with EBC RH+/HER2- represented by high-NOLUS is similar to that reported in the literature. Patients with high-NOLUS have worse outcomes in DR and CSS. The NOLUS model is useful to identify non-luminal subgroups in RH+/HER2- EBC in the absence of genetic platforms.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.