Neoadjuvant chemotherapy in invasive breast cancer results in a lower axillary lymph node count

BACKGROUND: It is essential to have the highest level of confidence in axillary staging assessment. Many surgeons and pathologists believe that fewer lymph nodes are present in axillary dissection specimens of women treated by neoadjuvant chemotherapy. Consequently, the purpose of this study was to compare the lymph node counts of axillary dissection specimens from patients having received neoadjuvant chemotherapy with those of patients treated with primary operation. STUDY DESIGN: A retrospective analysis of a prospective database from our institution identified 283 women with invasive breast cancer who underwent level I and 11 axillary lymph node dissections. Women from the neoadjuvant chemotherapy group (n = 107) were compared with those from the primary surgery group (n = 176). The total number of lymph nodes harvested was considered as a continuous variable, but also dichotomized into two categories (< 10 and ! 10). Its correlation with the different variables was analyzed. RESULTS: The median number of lymph nodes retrieved in the neoadjuvant chemotherapy group was 10.0 (range 0 to 38) compared with 12.5 (range 0 to 30) in the control group (p = 0.002). There were also significantly more patients with fewer than 10 lymph nodes recovered in the neoadjuvant group (45 versus 28%, p=0.007). Logistic regression showed that neoadjuvant chemotherapy was the only factor associated with retrieval of fewer than 10 lymph nodes. CONCLUSIONS: This study suggests that administration of neoadjuvant chemotherapy to breast cancer patients results in a reduced number of lymph nodes retrieved in the axillary dissection specimens.