Abstract P4-07-49: Neoadjuvant therapy in Asian breast cancer patients with early & locally advanced breast cancers – A contemporary experience from a large tertiary hospital in Singapore
Authors: Zhang Zewen , Ma Jun , Tan Jasmine Yun Ting , Ong Whee Sze , Kamis Sulastri , Yang Grace , Tan Benita Kiat Tee , Tan Veronique Kiak Mien , Tan Tira J. 
Published: March 2023

Background: Non-metastatic breast cancers (BC) are increasing treated with neoadjuvant therapy (NAT). Complete pathological response (pCR) is associated with improved survival. Early identification of care needs during NAT is crucial. We report our institution’s experience with NAT. Methods: A prospectively recruited cohort diagnosed with BC, referred to NAT program at SingHealth acute hospitals between June 2020 and June 2021. Demographics, clinical data, pCR (absence of invasive carcinoma in breast and axilla), and Functional Assessment of Cancer Therapy Breast (FACT-B) as quality of life (QOL) measure were collected. Definition of young BC (YBC) were ≤40 years, older adults (OA) ≥65 years. Results: Among 119 eligible patients, 7 (6%) were clinically stage 1, 71 (60%) stage 2, and 41 (35%) stage 3. Twenty-eight (24%) were triple negative (TNBC; defined as HER2- hormonal receptor 0-10% [HR-]), 26 (22%) HER2+ HR-, 45 (38%) HER2+ HR+, 20 (17%) HER2- HR+. Among 71 HER2+ BC, two-thirds received anthracycline (A) based chemotherapy, a quarter A-sparing and remaining 9% taxane only. Majority (89%) received dual HER2 blockade. Among TNBC, 28 (71%) received additional platinum and 2 (7%) immunotherapy. Majority (77%; n=92) completed NAT. Toxicity was main reason for incompletion. Three patients did not undergo surgery: 1 defaulted, 1 demised and the last patient’s surgery was not due at analysis. Of the 116 who underwent surgery, 23 (20%) had breast conservation and 93 (80%) mastectomy. Forty-nine (42%) achieved pCR - 12 (43%) TNBC, 17 (65%) HER2+ HR-, 20 (44%) HER2+ HR+ and 0 in HER2- HR+ (p &lt; 0.001). The pCR rates were also lower by increasing age (Multivariable OR 0.93; 95% CI, 0.90-0.97). Baseline median FACT-B scores was 117 (IQR 102-126) for the cohort: 108 for YBC, 116 for OA and 120 for the rest (p=0.200). At baseline, median score was 28, 24, 18, 22 and 27 in physical, social, emotional, functional wellbeing and BC subscale, respectively, and YBC and OA patients had lower social wellbeing scores than the remaining cohort (22 vs 24, p=0.011). Conclusion: Highest pCR were observed with HER2+ followed by TNBC. Pre-operatively, FACT-B scores were comparable by demographics, staging and tumor subtypes. However, care must be paid to social wellbeing for women in age extremes undergoing NAT.

Citation Format: Zewen Zhang, Jun Ma, Jasmine Yun Ting Tan, Whee Sze Ong, Sulastri Kamis, Grace Yang, Benita Kiat Tee Tan, Veronique Kiak Mien Tan, Tira J. Tan. Neoadjuvant therapy in Asian breast cancer patients with early & locally advanced breast cancers – A contemporary experience from a large tertiary hospital in Singapore [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-07-49.