Patient-friendly scan could replace biopsy to assess hormone sensitivity in patients with metastatic breast cancer News
A specific PET scan (FES-PET) that displays the hormone sensitivity of metastases predicts the outcome of a biopsy with 99% certainty. The determination of hormone sensitivity, i.e. the presence of oestrogen receptors (ER), is of great importance for the treatment and prognosis of metastatic breast cancer. A biopsy is the standard, but this procedure cannot always be safely performed. The finding that the FES-PET scan is a patient friendly alternative to determine the hormone sensitivity, is therefore important for the thousands of women diagnosed with metastatic breast cancer each year.

These findings are the result of the largest global study that has been conducted on the topic until now by multidisciplinary teams of five Dutch centres, under the leadership of oncologists Carolien Schröder (Netherlands Cancer Institute/University Medical Center Groningen) and Liesbeth de Vries (UMCG). The results of the study were published on May 18th in the influential Journal of Clinical Oncology. 

To map out potential metastases in breast cancer patients, these patients undergo certain tests and scans. These include a standard CT scan, PET scan or bone scan, and a biopsy of a metastasis. A biopsy is highly important for establishing the characteristics of the breast cancer, such as the ER. This receptor is present in roughly 70% of all breast cancer cases, and makes the cancer sensitive to hormone treatments. It is important to establish these characteristics yet again in the case of metastases, as they may change over the course of time. This means that metastases in breast cancer that was previously hormone sensitive may not also be sensitive (and vice versa). In addition, characteristics may differ across metastases. The specific FES-PET scan, however, displays ER across the entire body. In the Dutch IMPACT study it was investigated whether the addition of specific PET scans, such as the FES-PET scan, to standard testing would be useful. 

The current study demonstrates that in FES-PET uptake above a certain threshold (maximal standard uptake value > 2,5), the biopsy also shows ER in 99% of cases. The FES-PET scan is therefore highly reliable. ‘A biopsy provides more information besides the ER, and will therefore remain relevant. But if a biopsy cannot be safely performed, the FES-PET scan is an excellent alternative to determine hormone sensitivity in metastatic breast cancer. This is of direct importance in daily clinical practice. In addition, we know that patients prefer a scan to a biopsy’, says medical oncologist Schröder. The aim is thus to make the FES-PET scan as widely available as possible and to include it in guidelines. 

The study was conducted by five Dutch centres: the UMCG in Groningen, the Amsterdam UMC at VU Amsterdam, UMC Utrecht, Erasmus MC in Rotterdam, and Radboudumc in Nijmegen.  ‘Through this collaboration, we were able to compile a large cohort of patients with recently metastasized breast cancer. In addition, by conducting the study with these five centres, all the protocols for specific scans, biopsies, and other procedures were standardized. This study provides a wealth of information that may eventually support optimal prediction of which patient will react to which type of therapy. As a result, the prospects for women with metastatic breast cancer can hopefully be further improved in the future’, explains Schröder.    

This study was made possible by the Dutch Cancer Society (KWF), grants 5565 and 12347.