Radiation-Induced Esophagitis Exacerbated by Everolimus

Background: Everolimus, a potent mammalian target of rapamycin (mTOR) inhibitor, has shown anticancer activity against various types of cancer, including renal cell carcinoma (RCC); however, little information is available on the efficacy and safety of the combination of everolimus and radiotherapy. We report a case of radiation-induced esophagitis that might have been exacerbated by the sequential administration of everolimus. Case Presentation: A 63-year-old Japanese man with RCC complained of back pain, and magnetic resonance imaging revealed vertebral metastases. He received radiotherapy (30 Gy/10 fractions) to the T6-10 vertebrae. Everolimus was administered immediately after the completion of radiotherapy. One week later, he complained of dysphagia, nausea and vomiting. An endoscopic examination of the esophagus showed erosive esophagitis in the middle to lower portions of his thoracic esophagus, corresponding to the irradiation field. Conclusion: Clinicians should be aware that everolimus might lead to the unexpected exacerbation of radiation toxicities.