New research being done in Stockholm, Sweden, has found that between 15 and 33 percent of breast cancer tumors change their hormonal status during the course of the disease. This finding is of major clinical importance because (1) it indicates that many breast cancer patients are not receiving optimal treatment for their particular type of cancer, and (2) by monitoring changes in a tumor’s hormonal status, oncologists will be better able to provide therapy specifically targeted to the tumor’s change in hormonal makeup.

Hormone Receptor Status

You’re probably familiar with the classification of breast cancer tumors as either ER-positive or negative, PR-positive or negative, and HER2 positive or negative. When the biopsy is done, and the tumor tissue tested, the ER (estrogen) and PR (progesterone) receptor status tests show whether one or both of these hormones is helping to grow the cancer. Cancers that are hormone positive can be treated by hormone suppressing drugs; hormone negative cancers may respond to other methods. Patients with hormone negative cancers are usually then tested for HER2 (human epidermal growth factor receptor 2) status. If the HER2 test is positive, treatment such as Herceptin is normally given.

Treatment Based on Hormone Receptor Status

Once the hormone status of the tumor is determined, the treatment protocol is based on the results of the original tests. It is not common practice to test for a change in hormonal status (by performing additional biopsies) during the course of treatment, and often not for a relapse either. The study being done in Stockholm has the potential to radically alter this accepted norm.

Study Finds Hormone Status Changes During Disease

The Stockholm study looked at changes in tumors in multiple relapses in breast cancer patients. In numerous cases, the researchers found significant tumor instability throughout the tumor progression. So much so that one in three tumors (or approximately 33%) change their ER or PR hormone receptor status, and the HER2 status changed for 15 percent of patients. Further, approximately 16 percent of the patients had tumors whose hormonal makeup changed back and forth during the progression of the disease.

Better Treatment Options Could Result

While this is all fascinating in the abstract, what does it mean for the newly-diagnosed breast cancer patient? Or, for that matter, the patient who has just learned she’s had a relapse? Up until now, treatment has been based on the initial testing of the tumor. For instance, ER positive patients might be put on Tamoxifen; HER2 positive patients, Herceptin, and so forth. All well and good, but if the hormone status of the tumor is changing during the course of the treatment, chances are the treatment will no longer be effective. Or at least not as effective.

What this study suggests is that the hormonal status of the tumor should be monitored throughout treatment, and if a relapse should occur, an in-depth and thorough re-testing must be done. This means more frequent biopsies of the tumor, as opposed to the norm of one initial biopsy. Insurance companies will balk at the cost. Some doctors may be reluctant to embrace new diagnostic procedures. Hopefully, though, the promise of better-targeted treatment throughout the course of the disease will, in the long run, outweigh these concerns.

What Are My Options?

This research is still in the clinical trial stage, so it will be a while before we begin to hear more about it in the mainstream media. In the meantime, share this information with your medical team, and learn as much as you can about your diagnostic options. It could mean the difference between months of useless treatment versus a shorter, better-targeted treatment plan.