Key Points
• In metastatic breast cancer, targeting the cell cycle has emerged as standard treatment. Cyclin-dependent kinase inhibitors (CDKIs), as well as radiotherapy (RT), are mainstays of treatment. In the current review, the authors assessed the safety and efficacy of treatment with CDKIs + RT.
• The authors concluded that “the combination of CDKI + RT allows an overall satisfying disease control, proving to be effective and causing a grade of toxicity influenced by some factors as the site of irradiation, leaning to favourable outcomes for sites as liver, spine or brain and to poorer outcomes for thoracic lesions or sites close to viscera; controversial evidence is instead for bone treatment. Toxicity also varies from patient to patient: in this context, the acknowledgment of toxicity and comorbidities history becomes of crucial importance. Therefore, according to our analysis we believe that the association of CDKI + RT might be effective and safe, and it is surely deserving more deepening through further analyses.”
• In the aggregate, the researchers found that radiotherapy appeared safer at the level of the spine vs the chest wall/lung. The site of targeted metastases, however, is critical, and if too close to the viscera (e.g., bowels), adverse effects could be so severe that ceasing combination therapy is necessary.