Colonoscopy plays an important role in detecting colorectal neoplasms in patients with gastric neoplasms

BACKGROUND Gastric cancer (GC) and colorectal cancer (CRC) are the fifth and third most common cancer worldwide, respectively. Nowadays, GC is reported to have a potential predictive value for CRC, especially for advanced CRC. AIM To evaluate the necessity of colonoscopy for gastric neoplasm (GN) patients. METHODS Four databases, including PubMed, EMBASE, the Cochrane Library, and Ovid, were used to perform the search strategy on May 2, 2023. The prevalence of colorectal neoplasms (CRN) and baseline characteristics were compared between the neoplasm group and the control group. Continuous variables are expressed as the mean difference and standard deviation. Relationships of categorical variables in the two groups are expressed as odds ratios (OR) and 95% confidence intervals (95%CIs). Subgroup analysis according to different kinds of GNs was conducted for more in-depth analysis. The results of this study are represented by forest plots. Publication bias was evaluated by a funnel plot. All data analyses were performed by STATA SE 16.0 software. RESULTS A total of 3018 patients with GNs and 3905 healthy controls (age and sex matched) were enrolled for analysis. After comparing the prevalence of CRNs between the two groups, CRNs were detected significantly more frequently in GN patients than in controls (OR = 1.69, 95%CI = 1.28 to 2.23, I-2 = 85.12%, P = 0.00), especially in patients with GC (OR =1.80, 95%CI = 1.49 to 2.18, I-2 = 25.55%, P < 0.1). Moreover, other risk factors including age (OR = 1.08, 95%CI = 1.00 to 1.17, I-2 = 90.13%, P = 0.00) and male sex (OR = 2.31, 95%CI = 1.26 to 4.22, I-2 = 87.35%, P = 0.00), were related to the prevalence of CRNs. For patients in the GN group, body mass index (BMI, OR = 0.88, 95%CI = 0.80 to 0.98, I-2 = 0.00%, P = 0.92) and smoking (OR = 1.03, 95%CI = 1.01 to 1.05, I-2 = 0.00%, P = 0.57) were protective and risk factors for CRNs, respectively. CONCLUSION Patients are recommended to undergo colonoscopy when diagnosed with GNs, especially GC patients with a low BMI and a history of smoking.