Among women with recurrent breast cancer, sites of cancer recurrence may have HER2 of hormone-receptor status that differs from the primary tumor. As such, individual biopsies of sites of cancer recurrence may be required in order to ensure optimal treatment. These findings were recently reported at the 2008 annual meeting of the American Society of Clinical Oncology.
When a suspicious area or lump in the breast is discovered, a physician will perform a biopsy. During a biopsy, cells are removed for examination in the laboratory to determine whether cancer is present. Other information is also obtained from the biopsy sample, which will play an important role in treatment decisions; this may include HER2 and hormone-receptor status.
It has been assumed that when breast cancer recurs, the sites of relapse will have characteristics similar to the primary tumor, including HER2 and hormone-receptor status. As a result, treatment options for recurrent breast cancer tend to be determined by biopsy results from the initial diagnosis. However, a few small studies have indicated that in some patients, sites of relapsed breast cancer may actually have different HER2 and hormone-receptor status from the original tumor. If this is the case, the relapsed disease may not respond to treatment options that were effective in the primary cancer.
Researchers from Canada recently analyzed data from a previous study involving patients identified by the British Columbia Cancer Agency Breast Cancer Outcomes Unit who had been diagnosed with primary breast cancer. These patients had experienced a local, regional, or distant relapse of their breast cancer. Tumor samples were analyzed for HER2 and hormone-receptor status of both the primary and relapsed tumors.
- 28% of tumors had changes in estrogen receptor, progesterone receptor, and/or HER2 status between the primary and relapsed sites of cancer.
- Both gain and loss of receptors were noted between primary and relapsed tumor sites; these gains and losses occurred among individuals who had received prior systemic chemotherapy, hormone therapy, or both.
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The researchers concluded that because nearly 30% of tumors had changes in hormone and HER2-receptor status between the primary and recurrent sites of cancer among breast cancer patients, biopsies of recurrent sites may be an important step in determining optimal treatment options. They add that further study regarding this issue is warranted.
Breast cancer patients who have experienced a recurrence of their disease may wish to discuss with their physician the risks and benefits of biopsies of recurrent sites of cancer.
Reference: MacFarlane R, Speers C, Masoudi H, and Chia S. Molecular changes in the primary breast cancer versus the relapsed/metastatic lesion from a large populations-based database and tissue microarray series. Program and abstracts of the 44th American Society of Clinical Oncology Annual Meeting; May 30 – June 3, 2008; Chicago, Illinois. Abstract 1000.
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