Adequate period of surveillance in each stage for curatively resected gastric cancer: analyzing the time and rates of recurrence.

Surveillance after curative surgery for gastric cancer is conventionally performed for 5 years. However, the appropriate follow-up period remains controversial. This study retrospectively compiled a clinicopathological database of patients who underwent curative gastrectomy between 1975 and 2010 at Toranomon Hospital and were reviewed until March 2020. Analyzing the follow-up rate and recurrence rate for each stage in each postoperative year, we set each follow-up endpoint when the subsequent recurrence rate fell below 1%. A total of 5235 patients were eligible for inclusion in the study. The rate of patients followed up for 5 years was 90.3%. The rates of follow-up were 52.7% at 10 years, 38.3% at 15 years, and 10.3% at 20 years. Recurrence was confirmed in 850 patients in total (16.2%) and in 50 patients beyond 5 years. The adequate follow-up endpoints according to stage (with < 1% recurrence risk) were 2 years for stage IA, 4 years for IB, 6 years for IIA, 9 years for IIB, 7 years for IIIA, and 8 years for IV (curative). For stage IIIB and IIIC, the recurrence risk remained. The adequate surveillance duration of resected gastric cancer might be different in each stage. Although the follow-up duration for stage I disease could be reduced to less than 5 years, advanced gastric cancer such as stage III or IV disease has risk of recurrence beyond 5 years and therefore additional follow-up is required. These results could help decide the strategy for surveillance.