@article{Zhu2026, 
author = {Guiling Zhu and Yutong Li and Bingzhi Wang and Liyan Xue and Yuchen Jiao and Xiaobing Wang and Chunxia Du},
title = {Multiple Primary Malignancies in Patients With Gastric Cancer: A Retrospective Study in National Cancer Center of China},
year = {2026},
journal = {Cancer Innovation},
volume = {5},
number = {3},
pages = {e70063},
keywords = {gastric carcinoma, metachronous multiple primary malignancy, multiple primary malignancy, synchronous multiple primary malignancy},
url = {https://www.sciopen.com/article/10.1002/cai2.70063},
doi = {10.1002/cai2.70063},
abstract = {BackgroundGastric cancer (GC) is a prevalent malignancy in China, posing significant health challenges. The persistently high tumor incidence and the rising number of tumor survivors may elevate the risk of multiple primary malignancies (MPMs) in GC patients.MethodsWe conducted a retrospective study involving 11,045 patients diagnosed with gastric adenocarcinoma at National Cancer Center of China between 2010 and 2017. A 6‐month interval distinguished synchronous MPMs (SMPMs) from metachronous MPMs (MMPMs).ResultsOf all GC patients, 443 (4.01%) had MPM, with 75.85% being males and an average age of 60 at initial diagnosis. Among the MPM cases, 415 (93.68%) had two primary cancers (53.98% synchronous and 46.02% metachronous), 27 (6.09%) had three, and 1 (0.23%) had four, totaling 472 extra gastric cancer sites. Esophageal, colorectal, and lung cancers were the most prevalent concomitant malignancies, with esophageal cancer more frequent in synchronous cases and breast cancer (observed only in females) more frequent in metachronous cases (both p < 0.001). In patients with two primary cancers, the SMPM subset included more males (p < 0.001), with higher rates of smoking (p = 0.012), alcohol consumption (p < 0.001), and higher T stage at first diagnosis (p < 0.001). The MMPM subset included more females (p < 0.001), was younger at first diagnosis (p < 0.001), and more frequently underwent surgery after first diagnosis (p < 0.001).ConclusionsMPM occurring in patients with GC predominantly involve the esophagus, colorectum, and lung. Elderly male patients with smoking or alcohol use represent a higher‐risk group and warrant vigilant surveillance. This study provides a clinical and epidemiologic basis for future research on MPM in GC.}
}