The amount of surgery in patients with early breast cancer and complete clinical response to neoadjuvant systemic therapy

Abstract

BACKGROUND: Neoadjuvant systemic therapy for triple-negative and HER2-positive breast cancer can achieve a complete pathologic response in approximately 60% of patients. Pathological complete response to neoadjuvant systemic therapy is a predictive factor consistent with a positive prognosis which can be accurately determined by percutaneous vacuum aspiration biopsy. AIM: To evaluate the amount of surgery in the group of patients with triple-negative and HER2-positive early breast cancer whose complete pathologic response was confirmed by vacuum aspiration biopsy and who did not undergo standard surgery. MATERIALS AND METHODS: The following single-centre study has been conducted in the Russian Federation. Women aged 18 years old and older with unicentric (cT1-2N0-1M0 by classification TNM) triple-negative or HER2-positive breast cancer with complete clinical response after neoadjuvant systemic therapy according to imaging diagnostic methods. The patients underwent vacuum aspiration biopsy on the mammary gland under ultrusound control with standard amount of surgical intervention on the axillary region. In case when no invasive or in situ disease was detected, no further breast surgery was performed and the patients underwent standard radiation therapy. The survival with no tumor relapse in the ipsilateral mammary gland was assessed as the primary endpoint. The study is registered on сlinicaltrials.gov, NCT04293796. RESULTS: Between June 2020 and May 2022, twenty-seven (84.4%) patients (all women; mean age 47.5 (3268) years) were enrolled in the study and underwent visually controlled vacuum aspiration biopsy. The average initial tumor size was 20.5 (735) mm. 7 (25.9%) patients initially had metastases in the axillary lymph nodes confirmed by puncture biopsy; 15 (55.6%) patients had HER2-positive breast cancer, and 12 (44.4%) had triple-negative breast cancer. A study of vacuum aspiration biopsy samples showed that 6 (22.2%) patients had a residual tumor, and 21 (77.8%) patients achieved complete pathologic response (95% confidence interval 53.2 to 81.4). At a median follow-up of 12.4 months, there were no tumor relapses in the ipsilateral mammary gland in 21 patients with complete pathologic response confirmed by vacuum aspiration biopsy after neoadjuvant systemic therapy, as well as other relapses or progression of the disease. CONCLUSIONS: The patients with a complete pathologic response, which is confirmed by the vacuum aspiration biopsy method, who refused to perform surgery on the mammary gland do not demonstrate worse results with a short period of observation. However, additional prospective clinical studies are needed.