田島 陽介

A 73-year-old man with a history of perianal abscess and anal fistula for approximately 40 years visited our outpatient clinic because of anal pain. An anal tumor was found at the initial visit. Colonoscopy also revealed a circumferential rectosigmoid tumor located 15 cm from the anal verge. The initial diagnosis was double primary cancer: Stage ⅡB anal fistula cancer(T3N0M0)and cStage Ⅱa rectosigmoid cancer(cT3N0M0). He underwent abdominoperineal resection with curative intent. Histopathological examination revealed that both tumors were moderately differentiated adenocarcinoma. In addition, genetic testing revealed that both tumors were KRAS G12V mutated, BRAFV600E wild, and microsatellite stable. The final diagnosis was metastatic carcinoma of anal fistula caused by implantation from rectal cancer.

BACKGROUND: Initial chemotherapy (Initial-C) followed by surgery is a promising treatment strategy for peritoneal lavage cytology-positive gastric cancer (CY1 GC) with no other noncurative factors. The aim of this study was to investigate the survival advantage of Initial-C compared to initial surgery (Initial-S) for this disease according to the macroscopic type, which was associated with prognosis and the efficacy of chemotherapy in GC. METHODS: One hundred eighty-nine patients who were diagnosed with CY1 GC with no other noncurative factors at four institutions from January 2007 to December 2018 were enrolled. The patients were divided into a macroscopic type 4 group (N = 48) and a non-type 4 group (N = 141). The influence of initial treatment on overall survival (OS) in each group was evaluated. RESULTS: In the type 4 group, the 5-year OS rates of Initial-C (N = 35) and Initial-S (N = 13) were 11.6% and 0%, respectively (P = 0.801). The multivariate analysis could not show the survival advantage of Initial-C. In the non-type 4 group, the 5-year OS rates of Initial-C (N = 41) and Initial-S (N = 100) were 48.4% and 29.0%, respectively (P = 0.020). The multivariate analysis revealed that Initial-C was independently associated with prolonged OS (hazard ratio, 0.591; 95% confidence interval, 0.375-0.933: P = 0.023). CONCLUSIONS: Initial-C improves the prognosis of non-type 4 CY1 GC with no other noncurative factors. On the other hand, further development of effective chemotherapeutic regimens and innovative treatment strategies are required for type 4 CY1 GC.