Stanford Type A Aortic Dissection During Adjuvant Capecitabine Chemotherapy for Colorectal Cancer

Capecitabine, an oral prodrug of 5-fluorouracil, is widely used for gastrointestinal malignancies. While its coronary toxicity is well documented, large-vessel complications such as aortic dissection are rarely reported. We present a 65-year-old man with colorectal cancer who developed Stanford type A aortic dissection 3 days after initiating adjuvant capecitabine therapy. Imaging revealed extensive dissection from the ascending to the abdominal aorta. Emergency hemiarch replacement was successfully performed. The absence of prior cardiovascular disease, close temporal relationship, and known vasotoxicity of fluoropyrimidines suggest a likely association. Fluoropyrimidines may induce endothelial injury, vasospasm, and hypertension. A history of smoking in our patient may have contributed to vascular susceptibility. Capecitabine, though well tolerated, may rarely cause life-threatening vascular complications such as aortic dissection. Clinicians should maintain a high index of suspicion for atypical vascular symptoms during therapy.