Severe Gastrointestinal Mucositis Following Concurrent Palbociclib and Palliative Radiation Therapy.

Background/aim: Palbociclib is an FDA-approved cyclin-dependent kinase inhibitor for the treatment of advanced breast cancer. Limited information is available regarding the toxicity of palbociclib and concurrent radiation therapy.

Case Report: Herein, we report a case of esophageal toxicity in a patient treated with palbociclib and radiation therapy. A 63-year-old woman was treated with palbociclib followed by palliative radiation therapy. The patient presented three days after completing radiation therapy with severe odynophagia, and dysphagia and was found to have grade 2-3 esophageal ulcers. Palbociclib and radiation therapy was held on admission, and a resolution of her symptoms and improvement in her oral intake was noted at which time she was restarted on palbociclib with no further radiation treatment.

Conclusion: Caution is advised when patients are undergoing concurrent palbociclib and even low-dose palliative radiation treatment. In these patients, providers should maintain a high index of suspicion for toxicities such as dermatitis or mucositis.