Abstract P2-14-13: Single institute data to assess timing of surgery post neoadjuvant in breast cancer patients

Background: This study aims to analyze the impact of the time taken from the completion of neoadjuvant chemotherapy to surgery on patients' outcomes in terms of pathological response, overall survival and disease-free survival. There is no specific guideline for timing of the surgery. This study presents the experience of our institute's unique and large data of locally advanced breast cancer patients who received neoadjuvant systemic therapy.

Methods: This retrospective study evaluated patients diagnosed with Stage II and III breast cancer patients who received neoadjuvant chemotherapy, which was FEC and Taxotere +/-Herceptin depending on Her2 status of disease. Evaluation of the treatment outcome was based on the time interval between completion of neoadjuvant chemotherapy and surgery. Patients were selected from the time frame of January 2004 to December 2014. The effect of time interval was studied using two types of stratification. First stratification included time interval less than 4 weeks, 4-6 weeks and more than 6 weeks. Second stratification included patients with time interval <4 weeks, 4-7 weeks, and ≥8 weeks. Patients were also evaluated on the basis of receptor status ER, PR and Her2, and their outcomes.

Results: A total of 611 patients were identified. The patients were divided into two cohorts for better analysis. The first cohort showed 94 patients (15.4%) who had surgery within 4 weeks of their last dose of neoadjuvant chemotherapy, 378 (61.9%) within 4-6 weeks, and 139 (22.7%) ≥6 weeks. For the second cohort 94 patients (15.4%) had surgery within 4 weeks, 424 (69.4%) within 4-7 weeks, and 93 (15.2%) ≥ 8 weeks. Median OS and median DFS is not reached. OS at 5 years was 89.6% and DFS at 5 years was 74%. In both cohorts, OS and DFS were not significant when stratified to timing of surgery but the trend of DFS, although not statistically significant, was poor when patients had surgery more than 6 and 8 weeks. When patients were assessed on pathologic response stratified with timing of surgery, about 15% of patients had surgery ≥8 weeks, only 12.9% of those had complete pathological response compare to patients whose surgery was 6-7 weeks and complete pathologic response was 26% (p=0.02). In terms of receptor status, (ER-/HER-2+) patients had a statistically significant decrease in complete pathologic response if surgery was ≥8 weeks. However, ER+/HER-2-, (ER+/HER-2+), ER-/HER-2- had no difference in complete pathological response.

Conclusion: The above data indicates that our patients showed improved complete pathologic response if the surgery was performed within 8-weeks, especially for (ER-/HER-2+) patients. All patients post neoadjuvant had better OS and DFS trends if the surgery was performed between 4-6 weeks. The data suggests that early surgery helps complete pathologic response, and the necessary measures must be taken to identify any obstacles leading to delay in surgery and eliminating these obstacles.

Citation Format: Suleman K, Haque E, Mushtaq AH, Badran A, Alsayed A, Ajarim D, Twegieri T, Almalik O, Jastaniyah NT, Elhassan T, Alkhayal W. Single institute data to assess timing of surgery post neoadjuvant in breast cancer patients [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-14-13.