Posted by: bcconnections | July 26, 2012

Breast Cancer Tumor Markers Can Change Throughout Tumor Progression

Testing breast cancer tumors for the presence of hormone receptors (estrogen receptor (ER)/ progesterone receptor (PR)) and human epidermal growth factor receptor (HER2) is an important component of determining appropriate therapy for breast cancer patients.  Whether these tumor markers remain stable when a patient has a recurrence has become an area of active investigation.  A Swedish-based study reports that receptor status frequently differs between the primary tumor and the recurrence, and even between multiple consecutive recurrences.  According to the study report, ER status changes between the primary tumor and the recurrence 32.4% of the time, PR status 40.7% of the time, and HER2 status 14.5% of the time.  These findings have clinical relevance since changes in receptor status could influence a patient’s eligibility for therapies.  For example, if a patient whose primary tumor was HER2 negative had a relapse that tested HER2 positive, the patient would now be a candidate for receiving HER2-targeted therapies.  The authors conclude, “given that the therapy-predictive markers alter in clinically significant frequencies during tumor progression, biopsies should be taken as a routine procedure because they will have important implications for further therapy management (Lindstrom et al., Journal of Clinical Oncology;20:2601-8, http://jco.ascopubs.org/content/30/21/2601.abstract).”

The National Comprehensive Cancer Network (NCCN) acknowledges the potential therapeutic benefit that could result from a change in receptor status from negative to positive upon recurrence, but also cautions that retesting “carries with it the potential for denying a patient endocrine therapy/HER2-targeted therapy because of a false-negative on a second biopsy (Carlson et al., JNCCN, July 2012, Volume 12, Number 7, pages 821-829).”  Therefore, the NCCN recommends retesting tumor markers upon recurrence only in cases where ER/PR or HER2 status is unknown, originally negative or not over-expressed.  Furthermore, they remark that “clinical judgment remains important.  For patients with clinical courses consistent with hormone-receptor positive breast cancer, or with prior positive hormone receptor results, the panel agreed that a course of endocrine therapy is reasonable regardless of whether the receptor assay is repeated or is the result of the most recent hormone receptor assay.”

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Responses

  1. Thanks for this post. This is very interesting. I think in the past, biopsy upon metastasis has been avoided as it was considered too invasive. I think that, even now, it’s not even done consistently. As a breast cancer survivor, I’d rather know as much about the enemy as I can, in order to foil it. In a future post, I’d love to hear about discordance in hormone receptor status even within the same tumor and how that’s currently handled in the clinic. Thanks!

    • Great idea Diane, I’ll keep that topic in mind for a future post.


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