Objective: To explore the interaction of multi-target stool DNA (MT-sDNA), intestinal flora and environmental factors in the development of colorectal cancer, so as to provide insights into pathogenesis study of colorectal cancer. Methods: A total of 54 cases of colorectal cancer from the First Affiliated Hospital of Ningbo University were included in the case group and 51 healthy subjects were included in the control group. Demographic information, diet and family history of colorectal cancer were collected by a questionnaire survey. MT-sDNA, intestinal flora, cancer antigen 19-9 (CA19-9), carcinoembryonic antigen (CEA) and other tumor markers were detected. Interactions of MT-sDNA, intestinal flora and environmental factors with the development of colorectal cancer was analyzed by multifactor dimensionality reduction (MDR), crossover analysis and additive model. Results: The case group included 20 males (37.04%) and 34 females (62.96%), and had a mean age of (64.89±9.72) years. The control group included 24 males (47.06%) and 27 females (52.94%), and had a mean age of (53.94±10.33) years. MDR analysis showed that subjects with both high absolute intestinal flora indexes and positive MT-sDNA had an increased risk of colorectal cancer (OR=3.782, 95%CI: 1.190-5.034). Crossover analysis showed that subjects with positive MT-sDNA and >5 μg/L of CEA had an increased risk of colorectal cancer (OR=2.121, 95%CI: 1.162-4.033). Additive model analysis showed that MT-sDNA had positive additive interaction with CEA (SI=3.687, 95%CI: 1.229-7.238), and MT-sDNA had negative additive interaction with fruit intake (SI=0.145, 95%CI: 0.020-0.753). Conclusion Positive MT-sDNA can synergistically increase the risk of colorectal cancer with high intestinal flora index and CEA, and fruit intake can reduce the risk of colorectal cancer in MT-sDNA-positive population.

Abstract: Objective To investigate the willingness to receiving multitarget stool DNA (MT-sDNA) testing and factors affecting the payment among individuals receiving colonoscopy screening, so as to provide the evidence for the formulation and health economic evaluation of colorectal cancer screening strategies. Methods: Individuals at ages of 40 to 75 years that received colonoscopy screening in The Affiliated Hospital of Ningbo University Medical School from August 2021 to March 2022 were sampled. Participants' demographics, living behaviors, family history, willingness to receive MT-sDNA testing and willingness to pay for MT-sDNA testing were collected using questionnaire surveys, and factors affecting the willingness to receive and pay for MT-sDNA testing were analyzed using a multivariable logistic regression model. Results : A total of 546 respondents were enrolled, with a mean age of (56.25±8.66) years and including 282 men (51.65%). There were 504 respondents that were willing to receiving MT-sDNA testing (92.31%) and 480 that were willing to pay for the MT-sDNA testing (88.24%). Multivariable logistic regression analysis showed that a family history of colorectal cancer in first-degree relatives (OR=0.246, 95%CI: 0.068-0.888), history of hemorrhoids (OR=0.300, 95%CI: 0.109-0.826) resulted in low willingness to receive MT-sDNA testing, and recognizing the reliability of MT-sDNA testing (OR=5.749, 95%CI: 1.480-22.323), considering no difficulty in sampling for MT-sDNA testing (OR=32.042, 95%CI: 6.666-154.021) and considering a difficulty in sampling for MT-sDNA testing (OR=20.278, 95%CI: 4.405-93.354) resulted in high willingness to receive MT-sDNA testing, while recognizing the reliability of MT-sDNA testing (OR=5.003, 95%CI: 1.761-14.216), concern about the reliability of MT-sDNA testing (OR=4.166, 95%CI: 1.285-13.501), considering no difficulty in sampling for MT-sDNA testing (OR=6.558, 95%CI: 2.105-20.428) and considering a difficulty in sampling for MT-sDNA testing (OR=5.820, 95%CI: 1.810-18.720) resulted in high willingness to pay for the MT-sDNA testing among individuals receiving colonoscopy screening. Conclusion A family history of colorectal cancer in first-degree relatives, history of hemorrhoids and awareness of MT-sDNA testing are factors affecting the willingness to receive and pay for the MT-sDNA testing among individuals receiving colonoscopy screening.