Trifluridine and Tipiracil Hydrochloride Combination-Induced Interstitial Pneumonia: A Case Report.

We report a case of a 62-year-old male who was diagnosed with advanced rectal cancer. The attending gastro-enterologist initiated chemotherapy using capecitabine plus oxaliplatin and bevacizumab; however, this treatment regimen was discontinued, as the patient developed a skin rash. Once the skin rash improved, chemotherapy was re-initiated using a combination of trifluridine and tipiracil hydrochloride (TAS-102). The patient developed high fever and dyspnea 2 months after initiation of TAS-102. Chest high-resolution computed tomography showed bilateral diffuse ground glass opacities in all lung lobes with traction bronchiectasis. At this time, the gastro-enterologist consulted our department. The patient was put on non-invasive positive pressure ventilation due to worsening respiratory symptoms. The patient was suspected to develop TAS-102-induced interstitial pneumonia based on positive TAS-102 drug-induced lymphocyte stimulation test. The patient's respiratory symptoms and radiological findings improved after corticosteroid treatment. The corticosteroid dose was gradually decreased by 5 mg. Thereafter, chemotherapy was re-initiated using different anti-cancer agents.