A single-center retrospective safety analysis of cyclin-dependent kinase 4/6 inhibitors concurrent with radiation therapy in metastatic breast cancer patients.

Cyclin dependent kinases 4/6 (CDK4/6) inhibitors gained an essential role in the treatment of metastatic breast cancer. Nevertheless, data regarding their use in combination with radiotherapy are still scarce. We performed a retrospective preliminary analysis of breast cancer patients treated at our Center with palliative radiation therapy and concurrent CDK4/6 inhibitors. Toxicities were measured according to CTCAE 4.0, local response according to RECIST 1.1 or PERCIST 1.0 and pain control using verbal numeric scale. 18 patients (32 treated sites) were identified; 50% received palbociclib, 33.3% ribociclib and 16.7% abemacliclib. Acute non-hematologic toxicity was fair, with the only exception of a patient who developed G3 ileitis. During 3 months following RT, 61.1% of patients developed G 3-4 neutropenia; nevertheless no patient required permanent suspension of treatment. Pain control was complete in 88.2% of patients three months after radiotherapy; 94.4% of patients achieved and maintained local control of disease. Radiotherapy concomitant to CDK4/6 inhibitors is feasible and characterized by a fair toxicity profile, with isolated episodes of high-grade reversible intestinal toxicity. Rate of G 3-4 neutropenia was comparable with that measured for CDK4/6 inhibitors alone. Promising results were reported in terms of pain relief and local control of disease.

Radiotherapy and Tyrosine Kinase Inhibitors in Stage IV Non-small Cell Lung Cancer: Real-life Experience.

AIM: To investigate the role of conventional radiotherapy (RT) and stereotactic body radiotherapy (SBRT) in patients with epidermal growth factor (EGFR)-mutant or anaplastic lymphoma kinase (ALK) rearrangement-positive metastatic non-small cell lung cancer (NSCLC). PATIENTS AND METHODS: Fifty patients with EGFR-mutated or ALK rearrangement-positive NSCLC were treated at our Institution. Radiotherapy was delivered before, after or concomitantly with tyrosine kinase inhibitors (TKIs). Acute toxicities and overall survival (OS) were assessed. RESULTS: Radiotherapy was performed within 30 days before TKI, concomitantly with TKI and within 30 days after TKI in eight (16%), 33 (66%) and 9 (18%) cases, respectively. The median duration of TKI therapy in the whole series was 11.9 months. The median OS was 19.3 months and 1- and 2-year OS was 71.5% and 36.5%, respectively. The group treated with SBRT had a significant benefit in terms of OS (p=0.043). Only two grade 3 toxicities were reported. CONCLUSION: RT concomitantly or close to TKI administration in stage IV NSCLC was shown to be feasible and safe. Intriguing data on OS were also reported.