A case of durvalumab-treated double primary cancers of the colon and lung.

Cases of double primary cancers of the colon and lung are rare, and the treatment regimens are highly individualized. Here, we report a case of double primary cancers of the colon and lung. The patient underwent radical resection for cancer of the left colon (pT4aN0Mx, IIb). Two months later, he sought treatment due to chest pain and painful swelling in his left axilla for one month and was diagnosed with adenocarcinoma of the right lung (cT4N3M1c, stage IVB). At the time before receiving radical resection of the left colon tumor, a chest computed tomography examination showed a space-occupying lesion in the upper lobe of the right lung, but the histological analysis was not performed at that time because abdominal computed tomography examination suggested the presence of incomplete obstruction, and emergency radical resection for colon cancer was conducted. Molecular pathological examination of the lung mass at the most recent admission suggested KRAS mutation and strongly positive programmed cell death-ligand 1 (PD-L1). Considering the patient's pain and compression symptoms, he was given palliative radiotherapy for the lung lesion, followed by sequential durvalumab maintenance therapy, along with a capecitabine plus oxaliplatin (CAPOX) regimen for colon cancer for 3 months. The patient signed informed consent forms for all treatments. After the treatments, the patient achieved partial remission of the lung lesion and complete remission of the lymph node metastases in the neck and left axilla. The only toxic effects were chemotherapy-related grade II bone marrow suppression and grade I radiation-induced lung injury. No recurrence or metastasis was observed during the 6-month follow-up. After a trade-off between the efficacy and toxicity of the treatment regimen of double cancers, this patient was given an individualized treatment regimen-maintenance treatment with the low-toxicity durvalumab for anti-PD-L1 immunotherapy following palliative radiotherapy and evidence-supported 3-month CAPOX chemotherapy after surgery for high-risk stage II colon cancer. The regimen not only avoided possible toxic effects but also achieved a sufficient treatment intensity. We believe that the combined use of radiotherapy, chemotherapy and lowtoxicity immune-targeted drugs has good application prospects in the individualized treatment of patients with multiple cancers.