The Effect of Neoadjuvant Chemotherapy on Her-2 Status in Her-2 Negative Breast Cancer Patients: A Study on Pathological Response

Background The impact of neoadjuvant chemotherapy (NAC) on Her-2 status in low Her-2 breast cancer (BC) is not well understood. We assessed the change of Her-2 status in Her2- low and her-2 score 0 in BC patients following NAC. Methods A retrospective study involved a total 469 patients with BC, non metastatic included the study managed in privet hospitals in the Republic of the Sudan. Results A total of 469 patients were eligible and included. Post NAC, 250 (53.3%) patients had a Her-2 score of 0 (176 had unchangeable Her-2 score of 0 and 74 were changed from low Her-2 to Her-2 score 0), while 219 (46.7%) had a low Her-2 (151 had unchangeable low Her-2 and 68 were changed from Her-2 score 0 to low Her-2). Patients with unchanged low Her-2 or changed from low Her-2 score zero had a higher percentage of ER positivity (65.6% and 58.1%) than those with changes from Her-2 score 0 to low (61.7%) or with unchanged Her-2 score 0 (52.8%), respectively. Patients with low Her-2 post-NAC who maintained low Her-2 had higher grade, Ki-67, and ER+ status compared to those whose Her-2 status changed. Patients with a Her-2 score of 0 post-NAC had higher Ki-67 levels and were more likely to be ER+. There was no significant correlation between post-NAC changes in Her-2 status and RCB. Conclusion Changes in low Her2- expression were observed in post-NAC BC patients. Further investigation is needed to recognize the prognostic values of Her-2 changes in low Her-2-BC.