Correlation Between Pathologic Complete Response in the Breast and Absence of Axillary Lymph Node Metastases After Neoadjuvant Systemic Therapy

Abstract

Objective: The aim was to investigate whether pathologic complete response (pCR) in the breast is correlated with absence of axillary lymph node metastases at final pathology (ypN0) in patients treated with neoadjuvant systemic therapy (NST) for different breast cancer subtypes. Background: Pathologic complete response rates have improved on account of more effective systemic treatment regimens. Promising results in feasibility trials with percutaneous image-guided tissue sampling for the identification of breast pCR after NST raise the question whether breast surgery is a redundant procedure. Thereby, the need for axillary surgery should be reconsidered as well. Methods: Patients diagnosed with cT1-3N0-1 breast cancer and treated with NST, followed by surgery between 2010 and 2016, were selected from the Netherlands Cancer Registry. Patients were compared according to the pathologic response of the primary tumor with associated pathologic axillary outcome. Multivariable analysis was performed to determine clinicopathological variables correlated with ypN0. Results: A total of 4084 patients were included for analyses, of whom 986 (24.1%) achieved breast pCR. In clinically node negative patients (cN0), 97.7% (432/442) with breast pCR had ypN0 compared with 71.6% (882/1232) without breast pCR (P < 0.001). In clinically node positive patients (cN1), 45.0% (245/544) with breast pCR had ypN0 compared with 9.4% (176/1866) without breast pCR (P < 0.001). The odds of ypN0 was decreased in case of clinical T3 stage (OR 0.59, 95% CI 0.40–0.87), cN1 (OR 0.03, 95% CI 0.02–0.04) and ER+HER2- subtype (OR 0.30, 95% CI 0.20–0.44), and increased in case of breast pCR (OR 4.53, 95% CI 3.27–6.28). Conclusions: Breast pCR achieved after NST is strongly correlated with ypN0 in cN0 patients, especially in ER+HER2+, ER-HER2+, and triple negative subtypes. These results provide data to proceed with future clinical trials to investigate if axillary surgery can be safely omitted in these selected patients when image-guided tissue sampling identifies a breast pCR.

Survival in Cytologically Proven Node-Positive Breast Cancer Patients with Nodal Pathological Complete Response after Neoadjuvant Chemotherapy

“…Once patients with cytologically proven node-positive disease achieved axillary pCR, they showed improved DDFS and OS, compared with patients with residual axillary disease. This is in agreement with previous reports [ 18 , 19 , 20 , 21 , 22 , 23 ]. Axillary pCR remained prognostic for DDFS after adjustment for other prognostic factors such as clinical stage, ER, HER2, and NG.…”

“…Neoadjuvant chemotherapy (NAC) is one of the standard treatment strategies for operable invasive breast cancer, especially for patients with node-positive breast cancer in all subtypes [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. Various studies have demonstrated that axillary LN pathological complete response (pCR) after NAC is associated with improved prognosis in patients with clinically node-positive disease [ 18 , 19 , 20 , 21 , 22 , 23 ]. However, it is unknown whether patients with cytologically proven axillary node-positive breast cancer, who achieve axillary pCR after NAC have comparable prognosis to those with pathologically axillary node-negative disease who did not receive NAC.…”

Pathological Response to Neoadjuvant Chemotherapy and the Molecular Classification of Locally Advanced Breast Cancer in a Latin American Cohort

“…Several prognostic factors for pCR have been identified, among which the axillary node involvement, status of hormone receptor, and HER2, tumor grade, and the NACT regimen administered to patients are described . In this study, we identify that 43.9% ( n = 166) of cN+ patients were reported as ypN0, and only 32.5% ( n = 63) of ypN0 patients achieved pCR, whereas 98.4% ( n = 62) of patients who had pCR presented no axillary node involvement (ypN0).…”

“…In this study, it was identified that 47.6% ( n = 615) of the patients were in such clinical stages; this percentage was lower because the NCI FBCU had lack of prior treatment as a criterion for the inclusion of patients in the study. This study is unique because it collects patients with breast cancer exclusively in locally advanced stages, whereas similar studies have taken as a population patients with breast cancer in early stages of the disease, and some have included a portion of patients in locally advanced stages, but only IIB and IIIA .…”

“…In this study, we identify that 43.9% ( n = 166) of cN+ patients were reported as ypN0, and only 32.5% ( n = 63) of ypN0 patients achieved pCR, whereas 98.4% ( n = 62) of patients who had pCR presented no axillary node involvement (ypN0). Samiei et al showed that cN0 patients who achieve pCR after NACT have high probabilities of reaching ypN0, especially in the hormone receptor‐positive HER2‐positive, hormone receptor‐negative HER2‐positive, and triple‐negative subtypes of breast cancer .…”