Pan-European Expert Meeting on the Use of Metronomic Chemotherapy in Advanced Breast Cancer Patients: The PENELOPE Project

Introduction: Metronomic chemotherapy (mCHT) is a treatment regimen in which drugs are administered frequently or continuously and that maintains low, prolonged, and pharmacologically active plasma concentrations of drugs to avoid toxicity associated with traditional chemotherapy regimens, while achieving tumor response. Despite the increasing use of mCHT in patients with metastatic breast cancer (MBC) and the endorsement of mCHT in guidelines, no consensus exists about which patients may substantially benefit from mCHT, which agents can be recommended, and in which treatment setting mCHT is most appropriate. Methods: In October 2017, ten international experts in the management of breast cancer convened to develop a report describing the current status of the use of mCHT for the treatment of advanced breast cancer, based not only on current literature but also on their opinion. The Delphi method was used to reach consensus. Results: A full consensus was reached concerning the acknowledgement that mCHT is not simply a different way of administering chemotherapy but a truly new treatment option. The best-known effect of mCHT is on angiogenesis inhibition, but exciting new data are on the way regarding potential activity on immune system activation. The experts strongly suggest that the ideal patients for mCHT are those with hormone receptor (HR)-positive tumors or those with triple-negative disease. Independently of HR status, mCHT could be an advantageous option for elderly patients, who are often under-treated simply because of their age. Conclusion: Current data support the use of mCHT in selected patients with MBC. Funding: Pierre Fabre.