Determinants of pathological response to neoadjuvant chemotherapy in women with breast cancer in Kenya
Date of Award
Master of Medicine (MMed)
Dr. Shahin Sayed
Dr. Asim Jamal
Dr. Zahir Moloo
Pathology (East Africa)
Background: Breast cancer (BC) is the most common cause of cancer deaths in Kenya. Standard treatment involves surgery followed by adjuvant chemo/radiotherapy as appropriate. Neoadjuvant chemotherapy (NACT) facilitates surgery in locally advanced breast cancer. The Residual Cancer Burden (RCB) is an objective, standardised measure of pathological response to NACT. Pathological complete response (pCR) (RCB Class 0) is a robust prognostic indicator, used in clinical trials. This study aimed to use RCB to improve understanding of current practice and effectiveness of NACT for breast cancer patients at Aga Khan University Hospital Nairobi (AKUH, N.).
Methods: 67 breast cancer patients receiving NACT between March 2012 and March 2020 were identified. Pathological response was evaluated by RCB (Index and Class). Demographics, treatment, and tumour characteristics (e.g. grade, immunohistochemical subtype) in both core biopsy and resection specimens were analysed to determine their influence on RCB. The influence of RCB and NACT on outcome measures (local recurrence, distant metastasis, event-free survival (EFS) was analysed.
Results: Seven (12.3%) showed complete response (RCB 0, pCR), while 24 (42.1%) showed minimal response (RCB Class III) (n=57). Data showed trends towards better outcomes with decreasing RCB (p=0.215 for EFS, n=45), and towards lower RCB with increased tumour grade (core biopsy; p=0.269, n=48). In 45 cases with complete NACT regimen data, most received AC-T (n=22, 49%) and FEC-T (n=9, 20%). nine of 67 patients (13.4%) had Breast Conserving Treatment (BCT). Neither RCB, BCT, nor outcomes, were affected by NACT regimen. Six of 40 cases (15%) had clinically significant alterations in biomarker expression.
Conclusions: NACT achieved pCR rate of 12.3%, and a BCT rate of 13.4%. RCB index evaluation is feasible, and a useful addition to the standard pathology report following NACT. Alterations in biomarker expression necessitate re-evaluation of IHC subtype in the resection specimen.
Thairu, N. M. (2020). Determinants of pathological response to neoadjuvant chemotherapy in women with breast cancer in Kenya (Unpublished master's dissertation). Aga Khan University, East Africa.