Weekly Versus Three-Weekly Administration of Paclitaxel as Neoadjuvant Chemotherapy in HER2 Negative, Stage III Breast Cancer: A Comparison of Treatment Responses.

Objective: Neoadjuvant chemotherapy with doxorubicin (A) and cyclophosphamide (C) followed by taxane (T) (AC followed by T) is one of the standard regimens in locoregionally advanced breast cancer. Paclitaxel, a taxane, can be given either in a three-weekly or a weekly schedule. The aim of this study was to compare the efficacy in terms of the clinical and pathological response of three-weekly paclitaxel with weekly paclitaxel in the treatment of human epidermal growth factor receptor 2 (HER2)-negative, stage III breast cancer.

Methods: A quasi-experimental study was conducted from April 2022 to October 2023 in two centers in Dhaka, Bangladesh. Sixty-six patients were enrolled and divided equally into two arms. Arm-A patients received four cycles of AC followed by paclitaxel (175 mg/m2)three-weekly for four cycles. Patients in Arm-B received four cycles of AC followed by paclitaxel (80 mg/m2) weekly for 12 weeks. Patients were evaluated before, during, and after the completion of the chemotherapy to assess clinical outcomes and were assessed for the pathological response after surgical management.

Results: Pathological complete response (pCR) was achieved in 15 (25%) patients. Four patients (13.33%) in Arm A and 11 patients (36.66%) in Arm B had pCR. The difference was statistically significant (p 0.037). The p-value was 0.219 for response at the primary site and 0.13 for response in axillary disease. In both arms, patients with triple-negative receptor status had increased pCR (22.22% or two patients out of nine in Arm A, and 85.71% or six patients out of seven in Arm B) in comparison to hormone receptor (estrogen receptor (ER) and/or progesterone receptor (PR)) positive tumors (9.52% or two patients out of 21 in Arm A, and 21.74% or five patients out of 23 in Arm B). However, these differences were not significant.

Conclusions: After three-weekly administrations of four cycles of AC, the weekly administration of paclitaxel was found to be more effective in comparison to three-weekly administration of paclitaxel.