Frequency of HER-2/neu receptor positivity and its association with other features of breast cancer

Abstract

Background: Carcinoma breast is the commonest malignancy of females all over the world and second leading cause of death due to cancer among females. In Pakistan it is more common at a young age contrary to the West where it is more common in old age (after 60 years). The objectives of this cross sectional study were to determine the frequency of HER-2/neu receptor over-expression and its association with some of the features of breast cancer like patient age, ER/PR status, tumour size, histological grade and axillary lymph node involvement.

Methods: This study was conducted at Surgical C Unit, Postgraduate Medical Institute of Lady Reading Hospital, Peshawar, from January 2007 to December 2007. Study included all patients with breast cancer admitted in Surgical 'C' unit LRH, Peshawar for Modified Radical Mastectomy (MRM). The resected specimens were sent to histopathologist for immunohistochemical (IHC) studies (HER-2/neu receptor and ER/PR) and detailed histopathological analysis including tumour subtype, size, histological grade and involvement of axillary lymph nodes. Patients refusing HER-2/neu receptor immunohistochemistry were excluded from the study. Name, age, sex, other relevant data, detailed history and clinical examination findings and results of investigation were recorded. Data was analyzed with SPSS version 10.

Results: This study included 24 female patients of breast cancer having modified radical mastectomy (MRM). Age distribution ranged from 32-75 years with a Mean +/- SD of age 48.3 +/- 18.2 years. Fifteen out of 24 patients (62.5%) were >40 years, while nine patients out of 24 (37.5%) were <40 years of age. The HER-2/neu receptor status was found positive in 11 patients (45.9%) and negative in 13 patients (54%) of the total cases. HER-2/neu receptor positivity was not significantly associated with histopathological sub-type (p > 0.05), number of axillary lymph nodes involved (p > 0.05) and histological grade (p > 0.05). While, it was significantly associated with tumour size (p < 0.05) and negative ER/PR status (p < 0.05).

Conclusion: Due to high prognostic significance and frequency in Pakistani females with breast cancer, HER-2/neu receptor should be checked in all patients with breast cancer so that the positive cases should have herceptin therapy and benefit from anthracycline based chemotherapeutic agents which can improve survival in these patients.