Stockholm, Sweden: New research has found that breast cancer tumours change their hormonal status throughout the course of disease, whereas the decision about the most effective treatment for the patient is usually only based on one biopsy of the primary tumour. For some patients, biopsy verifications of any relapse will be very important because it may completely change their clinical management, a Swedish researcher will tell the 2011 European Multidisciplinary Cancer Congress  today (Monday 26 September). Dr. Linda Lindstrm, from the Karolinska Institutet Department of Oncology-Pathology, Solna, Stockholm, will say that her group's research is the first sizeable study to look at changes in tumours in multiple relapses in breast cancer patients.
"Our study demonstrates tumour instability in clinically used markers throughout tumour progression. We saw, for example, that one in three breast cancer patients alter oestrogen (ER) or progesterone (PR) hormone receptor status, and 15% of patients change human epidermal growth factor receptor 2, or HER2, status during the course of disease," she will say.
ER and PR receptor status tests show whether one or both of these hormones is helping to grow the cancer. Cancer that is hormone positive can be treated by hormone-suppressing drugs, whereas hormone negative cancers may respond to other types of treatment. Hormone negative patients are normally tested for HER2. If this test is positive, treatment such as Herceptin will usually be given.
The researchers studied breast cancer patients in the Stockholm healthcare region who had a recurrence of the disease between January 1, 1997 and December 31, 2007. Information on ER status in several relapses from the same individual was assessed in 119 patients: 33.6% of patients had changes in tumour status between the different sites of relapse (local, loco-regional and metastases) whereas 36.1% of the patients were stable ER positive, and 30.3%
|Contact: Mary Rice|
ECCO-the European CanCer Organisation