The primary objective of the study is to describe the tolerance profile of radiation treatments performed during systemic treatment with new drugs (molecular targeted therapies, immunotherapy, others).

Patients suffering from stage IV breast cancer undergoing a systemic treatment including: molecular targeted therapy, conjugated antibodies (ADCs), monoclonal antibodies, tyrosine kinase inhibitors (TKI), immunotherapy (ICIs), who are candidates for a radiation treatment (both palliative or curative), after being informed about the study and giving written informed consent, will be considered eligible for this observational study. This study aims to prospectively analyze the tolerance profile of radiation treatments performed during new generation systemic therapy.

Inclusion Criteria:

• Patients suffering from stage IV breast cancer
• Ongoing systemic treatment including: molecular targeted therapy, conjugated antibodies, monoclonal antibodies, tyrosine kinase inhibitors, immunotherapy (immunocheckpoint inhibitors)
• Candidates for radiation treatment (both palliative and curative).

Exclusion Criteria:

• Previous radiation treatment on the same site
• Absolute contraindications to radiotherapy
• Systemic treatment administered as part of a clinical trial

Patients suffering from stage IV breast cancer undergoing systemic treatment including: molecular targeted therapy, conjugated antibodies, monoclonal antibodies, tyrosine kinase inhibitors, immunotherapy (immunocheckpoint inhibitors)