Role of HER2 in brain metastasis of breast cancer: a systematic review and meta-analysis.

BACKGROUND Breast cancer is one of the most common cancers among women worldwide and the HER2 receptor plays an important role in its development and progression. This systematic review aimed to summarize the role of HER2 in brain metastasis in patients with breast cancer. MATERIALS AND METHODS We conducted a literature search by advanced search in title field using the Scopus, Pubmed, and Google scholar databases until the end of June 2014. With metastasis, metastatic, HER2, brain, and breast cancer, as terms of search we selected 31 articles, which were reviewed by two independent and blinded expert reviewers. The studies were first selected according to their titles and abstracts. Quality of the studies were then assessed using the STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) protocol for observational studies and CONSORT(Consolidation of Standards for Reporting Trials) protocol for clinical trials. For statistical analyses, we used STATA, version 11.0 software. Forest and funnel diagrams were drawn and for heterogeneity, index was also considered. Also we used meta regression analysis. RESULTS Finally, we reviewed 10 studies. The prevalence of brain metastasis in HER2- positive breast cancer patients was 24.9%. There was publication bias in the reviewed studies. Meta regression analysis showed that follow up time had no significant effect (p=0.396) on the prevalence of brain metastasis. CONCLUSIONS The results showed a high prevalence of brain metastasis in HER2 positive breast cancer patients.