A genetic test at the time of diagnosis, useful for predicting treatment response in breast cancer

Researchers at Hospital Clínic and IDIBAPS lead a study in which a genomic test performed at the time of diagnosis in breast cancer is useful to identify the real tumor subtype and provide valuable information regarding prognosis and the tumor response to chemotherapy. When transferred to the clinical practice, allows deciding within a multidisciplinary committee the best treatment and follow-up strategy in each case. The article has been published in the journal BMC Medicine and has been coordinated by Dr. Aleix Prat, head of the Onclology (oncology) Department at Hospital Clínic and the Translational genomics and targeted therapeutics in solid tumors IDIBAPS team. Researchers at the Vall d'Hebron Institute of Oncology (VHIO) and the University of North Carolina have also participated.

In the last decade, it has become apparent that gene expression-based data in breast cancer can provide useful biological, prognostic, and predictive information. Genomic tests are now performed in a selective way only after surgery in patients with hormone-sensitive tumors, in order to decide if further chemotherapy treatment is required. This study evaluates the possibility of using these tests in clinical practice in any type of breast cancer as well as their usefulness in predicting response to treatment with chemotherapy and prognosis before performing any intervention.

In the article published in BMC Medicine, genomic and clinical data of 957 patients with breast cancer, one of the largest series published, were evaluated to test the ability to identify the molecular tumor subtype and assess its usefulness in predicting tumor’s chemotherapy response and patient’s prognosis. Researchers have shown that the biology identified with genomic data is the most significant predictor of treatment response and survival beyond the 4-5 variables that are currently used in clinical practice. "In this study we have seen that incorporation of genomics into clinical practice would help us to better classify tumors and to establish the most appropriate treatment," explains Dr. Aleix Prat.

Thus, these genomic platforms allow to identify in a reproducible and reliable way the molecular breast cancer subtype and, when performed at the time of diagnosis, to predict sensitivity to chemotherapy and long-term survival. "At the Breast Cancer Unit at Hospital Clinic we have incorporated the test at the time of diagnosis and, before taking any treatment decision, we discuss the result within a committee with all the breast cancer specialists," explains Dr. Prat. The study also opens new opportunities for research in breast cancer, because "we are currently evaluating how the genomic changes during chemotherapy or with innovative biological drugs can help us to better predict patient’s response and survival," he concludes.

Article reference:

Response and survival of breast cancer intrinsic subtypes following multi-agent neoadjuvant chemotherapy.

Prat A, Fan C, Fernández A, Hoadley KA, Martinello R, Vidal M, Viladot M, Pineda E, Arance A, Muñoz M, Paré L, Cheang MC, Adamo B, Perou CM.

BMC Med. 2015 Dec 18;13(1):303. doi: 10.1186/s12916-015-0540-z.