The burden of stomach cancer remains high, particularly among Asian countries. Although Japan is known to achieve high survival from stomach cancer, little is known regarding the survival trends for recent years and survival by subsite and stage. We report age-standardised 1-, 3-, 5- and 10-year net survival for patients diagnosed with stomach cancer in Osaka, Japan.
We analysed patients diagnosed with primary stomach cancer and registered in the population-based cancer registry in Osaka Prefecture between 2001 and 2014. We used the non-parametric Pohar Perme method to derive net survival for each year. Both cohort and period approaches were used. Age was standardised using weights of the external population of the International Cancer Survival Standard. Multiple imputation was applied to handle missing information on subsite and stage before estimating age-standardised net survival by subsite (cardia and non-cardia) and stage (localised, regional and distant metastasis). We then examined general trends in the cohort-based survival estimates, as well as by subsite and stage, using linear regression.
A total of 97,276 patients were included in the analysis. Age-standardised net survival improved steadily (mean annual absolute change ≥1.2%). Net survival for both subsites improved, but cardia cancer showed 7–23% lower survival than non-cardia cancer throughout the study period. Five-year net survival remained high (≥80%) in the localised stage from the beginning of this study. Net survival increased steeply (≥1.4% per year) in the regional stage. Although 1-year net survival increased by 14% in the distant stage, 5-year and 10-year net survival remained below 10%.
Age-standardised net survival for stomach cancer in Japan improved during the study period owing to an increase in the number of patients with localised stage at diagnosis and improved treatment. Monitoring both short- and long-term survival should be continued as management of stomach cancer progresses.
- • Age-standardised net survival of stomach cancer in Osaka improved during 2001–2014.
- • Net survival improved as the number of localised stage cancer increased.
- • Survival of cardia and non-cardia cancer rose, but the survival gap did not narrow.
- • Increase in 5-year net survival was largest in regional stage from 32% to 52%.
- • One-year survival for the distant stage rose, but with no rise in the longer term.
The burden of stomach cancer remains high, particularly in Asian countries which accounted for 75% of the worldwide incidence and mortality in 2018 and 2019 . In Japan, stomach cancer had the second and third highest incidence and mortality, respectively in 2018 and 2019 but survival was reported to be relatively high (age-standardised 5-year net survival of 60.3%) among the high-burden countries . However, little has been reported on the details of shorter- or longer-term net survival. Although cardia stomach cancers can be expected to rise in Japan due to the rapid westernisation of lifestyle, the increasing trend in cardia cancer has not been consistently reported . We aimed to provide short- and long-term survival estimates of stomach cancer by subsite and stage and investigate their trends. We estimated age-standardised net survival for patients diagnosed with stomach cancer between 2001 and 2014, using data from the population-based cancer registry in Osaka Prefecture.