[A case report of recurrent lung metastasis after surgery for rectal cancer for which lung radiofrequency ablation therapy and long-term administration of FOLFIRI were effective].

: This case concerns a 50-year-old male patient who was diagnosed with rectal cancer without any obvious distal metastasis. The patient underwent abdominoperineal resection of the rectum with lateral lymph node dissection exclusively on the lesion side. An obturator lymph node metastasis was found, and histopathological tests revealed that the patient was in Stage IIIb. FOLFOX4 therapy was performed as postoperative adjuvant chemotherapy, and although temporary discontinuation was necessary due to abscesses in the buttocks, the patient completed 10 courses of chemotherapy. Lung metastasis was diagnosed when a chest computed tomography revealed a nodule 12 mm in diameter immediately above the diaphragm in the left S8. Since the nodule was a solitary tumor, radiofrequency ablation (RFA) therapy was performed, after which postoperative adjuvant chemotherapy was changed to FOLFIRI therapy. No obvious adverse events occurred, making it possible to continue the therapy without withdrawal. The lesions tended to gradually shrink, and during the 50th course of the therapy, the patient converted from partial remission (PR) to complete remission (CR). The FOLFIRI therapy was continued for another 6 months and then suspended for a while. The patient received 62 courses of FOLFIRI therapy in total. No sign of recurrence has been found. This case demonstrates the successful treatment and CR of recurrent lung metastasis after surgery for rectal cancer using lung RFA therapy and long-term administration of FOLFIRI.