Printer Friendly

HER2 status of metastatic tumor may differ from primary tumor

November 30, 2011

A new study published in the Journal of Clinical Oncology supports the need for biopsies of metastatic lesions to determine if HER2 status is the same (concordant) as in the primary tumor.  The researchers confirmed that metastatic lesions can be HER2-negative when the primary tumor was HER2-positive (discordant), and having this information is critical to determining patient prognosis and appropriate therapy.

In this retrospective study, Dr. Naoto Ueno and colleagues identified 182 patients who initially had been diagnosed with HER2-positive primary breast cancer between 1997 and 2008 at MD Anderson Cancer Center who also had metastatic tumor biopsy results available for review.  Of the 182 patients with HER2-positive primary tumors, 43 (24%) had discordant (HER2-negative) metastatic tumors.  The HER2 discordance rates differed significantly based on whether patients received chemotherapy for primary tumor treatment but not on the basis of whether patients received Herceptin.  Interestingly, patients with discordant HER2 status had shorter overall survival than did patients with concordant HER2 status (hazard ratio=0.43). 

In an accompanying study which looked at changes in ER and PR status in addition to HER2, Dr. Eitan Amir and colleagues also stress the importance of biopsying the metastatic tumor for receptor status (ER, PR, HER2).  "Clinicians alter immediate management in one of seven patients on the basis of results of the biopsy, and discordance is not then associated with detrimental effects on outcome."