Triple negative breast cancer: combining radiotherapy with PARP inhibitors
Dr Youlia Kirova, radiothérapeute au département de Radiothérapie de l'Institut Curie.
Physicians are often powerless when faced with triple negative breast cancer. This form represents 10 to 20% of breast cancers and responds to neither Hormone therapy nor Herceptin. It is characterised by a strong tendency to metastasis. This form of cancer is often found in patients carrying the BRCA1 and BRCA2 mutations. In this patient cohort, PARP inhibitors have obtained marketing authorisation for treatment of ovarian cancer.
Increasing effectiveness of radiotherapy through PARP inhibitors
One of the therapeutic priorities is to find new solutions to treat patients for whom neoadjuvant chemotherapy - administered before surgery - is not effective enough or those for whom surgery is not an option after this first treatment due to the size of the tumour growth or presence of metastatic disease. This is the goal of the phase-1 clinical trial, RadioPARP, coordinated by radiotherapy oncologist Youlia Kirova, which should be starting very soon at Institut Curie. Initially it aims to assess the tolerance of a combination of radiotherapy and Olaparib. This drug belongs to the PARP inhibitors family, a molecule known for its role in repairing DNA damage. The underlying idea in this combination is to prevent repair of damage caused by rays in the tumorous cells and thus lead to their destruction. “Olaparib is administered orally to patients”, explains Dr. Youlia Kirova. “Then we hope to see a radio-sensitising effect in the breast and lymph nodes.” The goal of this first clinical phase is to observe the tolerance of this combination in patients, as well as to assess its effectiveness.
In the long term, the hope is that we will be able to offer this therapeutic strategy before surgery to patients with triple negative breast cancer in order to:
- increase conservative surgeries
- improve the diagnosis while reducing rates of relapse and metastasis
This strategy could also be an additional option for patients whose cancer spreads after the first treatments. The first patient should be included in this study at the end of September 2016.