Controversies in monitoring metastatic breast cancer during systemic treatment. Results of a GIM (Gruppo Italiano Mammella) survey

Background: The optimal strategy for monitoring metastatic breast cancer (M-MBC) is unclear. Nevertheless, M-MBC influences patient's quality of life and it affects the use of resources in terms of both drugs and diagnostic exam prescription. We aim to disclose oncologists' approach on M-MBC, identifying controversial areas. Methods: An anonymous online survey was conducted among GIM members who, based on their on-field experience, shared their own method for M-MBC planning. Chi-square tests and Fisher exact tests were used as appropriate. Results: The survey was completed by 256 recipients (51%). The majority of them were medical oncologists. Approximately 50% of respondents reported that M-MBC was primarily based on the monitoring strategies used in clinical trials, and for 70% of them M-MBC should be evidence-based. Areas of controversies included the primary goal of M-MBC, the use of tumour markers, the optimal timing for baseline assessment and frequency of repeating testing. Respondents agreed on planning M-MBC before treatment's start and on discussing with the patient about the M-MBC strategy and on choosing CT-scan as the preferred reassessment imaging method. The most relevant factors influencing the M-MBC strategy were performance status, triple negative histology, exam's contraindication, the presence of clinically measurable disease, and treatment safety profile; on the contrary, patients' socio-economic status, exam's cost, and hospital's logistic limits were less relevant. Experienced oncologists seemed less prone to intensive follow-up. Conclusion: M-MBC strategy still has controversial issues and its potential clinical effects for breast cancer patients need ad hoc studies.