Prevalence of HER-2-Positive Invasive Breast Cancer: A Systematic Review from Iran

Background: The HER-2/neu gene is altered in 15-20% of breast cancer patients. Immunohistochemistry (IHC)is considered to be the most cost-effective method for HER-2 detection in many countries. Approximately 8,000new cases of breast cancer are observed annually in Iran. The aims of this study were to conduct a systematicreview of the literature on the rate of HER-2-positive breast cancer diagnosed by IHC in Iran.
Methods: Asystematic search of the medical literature using the Medline/PubMed, ISI and SID databases revealed articlespublished in the English and Persian languages evaluating HER-2-positive breast cancer in Iran.
Results: From22 studies, 3,033 patients were evaluated, of whom 1,350 were diagnosed as HER-2-positive by IHC HER-2testing. The mean percentage of HER-2-positive patients was 44.5%, which is higher than that recorded ininternational statistics. Results of this meta-analysis showed a significant heterogeneity between ratios. There wasa statistically significant difference between the results of pre- and post implementation of 2007 American Societyof Clinical Oncology/College of American Pathologists (ASCO/CAP) guideline. IHC HER-2 testing has beenperformed in Iran for over 10 years. Similar to many other countries, before establishment of an infrastructurefor IHC diagnostic tests, HER-2 testing was routinely performed in Iran. Our study showed that the statisticsreported from Iran varied widely; for instance, the rate of HER-2-positive cases varied from 23.3% to 81.0%.
Conclusions: Our results demonstrate that the lack of standardization and harmonization of this test have ledto marked variations in breast cancer diagnosis in Iran.