OBJECTIVE: To evaluate the association between clinico-pathological features and HER2 overexpression in breast cancer.
METHODS: This is a retrospective study conducted in the Department of Surgery, University Malaya Medical Centre. The association between HER2 overexpression, determined by immunohistochemistry, and other clinicopathological factors was evaluated in 996 patients with newly diagnosed breast cancer treated from 2005 to 2007 using univariate and multivariate logistic regression.
RESULTS: HER2 overexpression occurred in 30.3% of patients. On bivariate analysis, HER2 overexpression was inversely related to ER expression (p<0.01) and PR expression (p<0.01). This overexpression was associated with a higher tumour grade, lymphovascular positivity and infiltrating ductal carcinoma subtype. On multivariate analysis, HER2 overexpression was significantly associated with higher tumour grade (p= 0.018, CI 1.25-11.04), PR negativity (p= 0.002, CI 0.30-0.77) and lymphovascular positivity (p= 0.042, CI 1.01-2.12).
CONCLUSIONS: HER2 overexpression was observed in 30.3% of Malaysian female breast cancer patients. This group of patients represents a more aggressive subtype of breast cancer with higher tumour grade, PR negativity and lymphovascular positivity. No significant relationship was established between HER2 overexpression and age, race, lymph node, ER, pathology subtype and stage of disease from this study.
METHODS AND MATERIALS: Patients with T3-4, N2 M0 breast cancer diagnosed between January 2005 and December 2008 and who received at least one cycle of neoadjuvant chemotherapy were eligible for this study. Thirty-four patients were identified from the Chemotherapy Daycare Records and their medical records were reviewed retrospectively. The neoadjuvant chemotherapy regimen administered was at the discretion of the treating oncologist. Breast tumour size and nodal status was assessed at diagnosis, at each cycle and before surgery.
RESULTS: All 34 patients had invasive ductal cancer. The median age was 52 years (range 27-69). 65% had T4 disease and 76% were clinically lymph node positive at diagnosis. The median size of the breast tumour at presentation was 80 mm (range 42-200 mm). Estrogen and progesterone receptor positivity was seen in less than 40% and HER2 positivity, by immunohistochemistry, in 27%. The majority (85%) of patients had anthracycline based chemotherapy, without taxanes. The overall response rate (clinical CR+PR) was 67.6% and pathological complete responses were apparent in two (5.9%). 17.6% of patients defaulted part of their planned treatment. Recurrent disease was seen in 44.1% and the median time to relapse was 11.3 months. The three year disease free and overall survival rates were 52.5% and 58% respectively.
CONCLUSION: Neoadjuvant chemotherapy for locally advanced breast cancer in a Malaysian setting confers response and pCR rates comparable to published clinical trials. Patients undergoing neoadjuvant chemotherapy are at risk of defaulting part of their treatment and therefore their concerns need to be identified proactively and addressed in order to improve outcomes.