Trends in incidence rates of gastric second primary cancers (SPC) since the diagnosis of the corresponding first primary cancers (FPC). Incidence rates were estimated for and represented in the respective midpoint of the following intervals: 0 to <1 month, ≥1 to <2 months, ≥2 to <4 months, ≥4 to <6 months, ≥6 months to 1 year, and then for each year of follow-up.