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.
MATERIALS AND METHODS: Patients who were treated with first line palliative chemotherapy for de novo MBC from 2002-2011 in UMMC were identified from the UMMC Breast Cancer Registry. Information collected included patient demographics, histopathological features, treatment received, including the different chemotherapy regimens, and presence of FN and TRD. FN was defined as an oral temperature >38.5° or two consecutive readings of >38.0° for 2 hours and an absolute neutrophil count <0.5x109/L, or expected to fall below 0.5x109/L (de Naurois et al, 2010). TRD was defined as death occurring during or within 30 days of the last chemotherapy treatment, as a consequence of the chemotherapy treatment. Statistical analysis was performed using the SPSS version 18.0 software. Survival probabilities were estimated using the Kaplan-Meier method and differences in survival compared using log-rank test.
RESULTS: Between 1st January 2002 and 31st December 2011, 424 patients with MBC were treated in UMMC. A total of 186 out of 221 patients with de novo MBC who received first line palliative chemotherapy were analyzed. The mean age of patients in this study was 49.5 years (range 24 to 74 years). Biologically, ER status was negative in 54.4% of patients and Her-2 status was positive in 31.1%. A 5-flourouracil, epirubicin and cyclophosphamide (FEC) chemotherapy regimen was chosen for 86.6% of the cases. Most patients had multiple metastatic sites (58.6%). The main result of this study showed a FN rate of 5.9% and TRD rate of 3.2%. The median survival (MS) for the entire cohort was 19 months. For those with multiple metastatic sites, liver only, lung only, bone only and brain only metastatic sites, the MS was 18, 24, 19, 24 and 8 months respectively (p-value= 0.319).
CONCLUSIONS: In conclusion, we surmise that FEC is a safe regimen with acceptable FN and TRD rates for de novo MBC.