Gastric cancer is the fifth most common cancer and the second leading cause of cancer death worldwide.
The epidemiology of gastric cancer has substantial geographical heterogeneity, and its incidence can vary 10-fold between high-risk and low-risk countries. Also, geographic variability in prognosis for gastric cancer is well documented. So, the 5-year survival rate is 65 – 70% in South Korea and Japan while it is around 20 – 30% in the other countries.
In the Eastern series (primarily from South Korea and Japan) higher survival rates were reported when compared to Western patients at the same stage of the disease following the same surgery. The highest survival rate in the mentioned countries mainly is attributed to population screening that has led to the diagnosis of cancer at early stages in most of the cases.
Epidemiological studies revealed linear correlation between the incidence of gastric cancer and relative survival but real impact of this factor on prognosis remains uncertain.
Even molecular studies conducted on Eastern and Western patients revealed no potential factors that could impact on differences in survival.
The phenomenon can generate some hypotheses that need to be studied in a large cohort of patients:
- In regions with lower proportion of EGC adjuvant chemotherapy might demonstrate more effectiveness compared to the regions with higher proportion of EGC due to more percentage of cases with possible synchronous occult distant metastases;
- In regions with highest proportion of EGC endoscopic mucosectomy can be performed more frequently without fear of recurrences in regional lymph nodes;
- The proportion of IV stage-gastric cancer in a large cohort of patients can predict the approximate prognosis for gastric cancer of any resectable stage after radical intent surgery;
- This phenomenon can concern not only gastric cancer also other cancers with high incidence rate.
This article was published on the 30th of July, 2020 in Acta scientific medical journal by Ramiz Bayramov, a senior author in the department of Oncology, Azerbaijan Medical University, Baku, Azerbaijan.
