Pathological complete response to neoadjuvant chemotherapy in luminal breast cancer is extremely low so its role is very controversial. We investigated whether the use Oncotype DX recurrence score ® could improve this response.We performed the Oncotype Dx in 103 patients with early breast cancer with high-risk clinical criteria to receive neoadjuvant chemotherapy. We reported the pathologic complete response (pCR) and its association with Oncotype DX.Median age was of 51 (24-87), median tumor size of 26 mm and 51 (57%) patients had initial node involvement. Median estrogen and progesterone receptor by histoscore was 280 and 40 and median Ki67 value was 30. 50 patients were less than 50 years old. Median Oncotype score was 30 (12-76) and 15 (14,6%) in the 11-18 score interval, 21 (20,4%) in the 18-25 and 67 (65%) with a score greater than 25. 24 (23,3%) patients obtained pCR, 22% in initial node involvement and 25% in not nodal involvement.The Oncotype DX its highly correlated with pCR (OD: 1,059, p: 0,004) in the multivariable analysis and in patients with Oncotype DX RS≥25 there was a strong correlation (OD: 18,295, P:0,005). pCR according with age (less or more than 50) and Oncotype Dx interval score is reported in the table.

Conclusion: Oncotype DX recurrence score ® predicts with great accuracy the pathologic complete response. Patients with RS 11-25 had a very low pCR, whereas patients with RS>25 achieve a 34% of pCR. Based on initial considered High risk Score (>31) we achieve a total of 18 to 42 patients of pCR (42%). Oncotype DX recurrence score ® allows a very considerable increase in the complete pathological responses after neoadjuvant chemotherapy, so it should be considered when selecting the patients who should receive neoadjuvant chemotherapy.

LESS THAN 50 YEARSMORE THAN 50 YEARS
ONCOTYPETOTALpCRTOTALpCR
RS 11-18 10 0 (0%) 0 (0%) 
RS 18-25 10 1 (10%) 11 0 (0%) 
RS > 25 30 11(36%) 37 12 (32%) 
LESS THAN 50 YEARSMORE THAN 50 YEARS
ONCOTYPETOTALpCRTOTALpCR
RS 11-18 10 0 (0%) 0 (0%) 
RS 18-25 10 1 (10%) 11 0 (0%) 
RS > 25 30 11(36%) 37 12 (32%) 

Citation Format: Ariadna Gasol Cudós, Serafin Morales Murillo, Alvaro Rodriguez Galindo, Ona Pallisé Subirats, Jordi Melé Olivé, Carles Canosa Morales, Felip vilardell villellas, Douglas René Sanchez Guzman, Joel Veas Rodriguez. Improving pathological complete response in luminal breast cancer after neoadjuvant chemotherapy [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P2-12-10.