Regorafenib Induced Interstitial Pneumonia in a Patient With Refractory Rectal Cancer.

Regorafenib, a multi-targeted tyrosine kinase inhibitor (TKI), is indicated for refractory colorectal carcinoma, gastrointestinal stromal tumours (GIST), and hepatocellular carcinoma (HCC). We present a case involving a 66-year-old male patient with refractory colorectal cancer who developed interstitial pneumonia as a consequence of regorafenib therapy. Three months following the initiation of regorafenib administration, a chest computed tomography scan revealed bilateral ground-glass opacities, a characteristic finding in interstitial lung disease. This case illustrates a relatively rapid progression of regorafenib-induced interstitial lung disease following its radiographic manifestation. Clinicians should remain vigilant for this potential pulmonary toxicity in patients receiving regorafenib, even with an apparently short latency period after treatment commencement. Early recognition and prompt intervention are crucial in managing this adverse event.