BETTER TO STUDY HER-2 IN METASTATIC LESIONS

Breast Cancer Res Treat. 2009 Jan;113(2):301-6. Epub 2008 Feb 14.

Related Articles, Links

HER-2/neu expression in primary and metastatic breast cancer.

Lower EE, Glass E, Blau R, Harman S.

Department of Internal Medicine, University of Cincinnati College of Medicine, Holmes, Room 1001, Eden Avenue and Albert Sabin Way, Cincinnati, OH 45267-0565, USA. ELower@ohcmail.com

Introduction Trastuzumab is a highly effective therapy for the treatment of HER-2/neu positive breast cancer. To maximize benefit and minimize unnecessary toxicity, patient selection is essential. Currently HER-2/neu analysis is routinely performed only for primary invasive breast cancers, and trastuzumab therapy is recommended based on primary analysis only. Methods Using immunohistochemistry, we performed a retrospective study comparing HER-2/neu expression in original primary to subsequent metastatic breast cancers. Results Tumors from 382 patients with metastatic breast cancer were studied. In 254 cases (66%) both primary and metastatic lesions were concordant. In 90 cases the primary lesion was HER-2/neu positive with the metastatic lesion negative; whereas, in 37 cases the primary lesion was HER-2/neu negative and the metastatic lesion positive. Primary HER-2/neu immunostaining was associated with a negative predictive value of 35.7%. Although all four groups were similar at diagnosis, survival differences were noted with the best survival experienced by patients with initial primary lesions HER-2/neu negative and subsequent metastatic lesions positive. Patients with hormone receptor and HER-2/neu positive primary lesions who received tamoxifen were more likely to have HER-2/neu positive metastasis. Conclusions The significant discordance between HER-2/neu expression in primary and metastatic tumors suggests that determination of HER-2/neu status in metastatic disease should be attempted.