Purpose. Evidence from industrialized/developed countries showed that colorectal cancer (CRC) incidence rates have significantly dropped due to the widespread use of colonoscopy. In Arab countries, however, the CRC had been reported to have increased. Despite the concerted effort in the primary prevention and widespread use of colonoscopy, to our knowledge, there have been no reports of the prevalence rate of CRC among colonoscopy recipients from Oman. This study aims to explore the CRC prevalence estimates over selected sociodemographic characteristics among colonoscopy-recipients at a tertiary hospital in Oman over five years of follow-up. The regional variations in Oman were also examined in this study. Methods. This hospital-based cross-sectional study reviewed reports of colonoscopies performed over 5-years of retrospective follow-up at a tertiary hospital in Oman. CRC prevalence estimates were calculated over age, gender, governorate, and time of follow-up. Results. A total of 442 CRC cases were enumerated among 3701 colonoscopies, with an overall CRC prevalence estimate of 11.9 per 100 colonoscopies (95% CI: 10.9, 13.0). Gender-specific CRC prevalence was higher among males compared with females (13.3 vs. 10.5). Age-specific CRC prevalence increased with advancing age, from 2.8 among those less than 40 years of age to 26.5 among aged 70 years or more. Regional CRC prevalence was highest among residents in Batinah Governorate. Over the 5-years of follow-up, there was a slow rise in CRC prevalence with an annual increment of 0.59%. Conclusion. The study provides supportive evidence for a steady increase in CRC prevalence over age categories and years of follow-up and depicted the variations of gender-specific CRC prevalence estimates over increasing age categories. The study calls for timely formulation and adoption of national CRC screening programs centered on the colonoscopy use as primary prevention and maximizing its utilization and efficiency.

BackgroundDespite the increase in colorectal cancer (CRC) in developing countries, primary prevention is still rudimentary due to limited use of colonoscopy for screening. Also, there is dearth of research of underlying nutritional risk factors for CRC occurrence in Arab countries, including Oman where CRC comprises for 9% of all‐cause mortality among adults.ObjectivesThis project aims to: 1) estimate standardized hospital‐based CRC prevalence among colonoscopy‐recipients attending a teaching hospital in Oman; 2) assess the nutritional status of study participants; and 3) explore the association between oxidative stress and CRC.MethodsThree studies will be conducted. The first study is an ambidirectional cross‐sectional study that will be performed over 5‐years of follow up, from January 2013 to December 2018. Participants will include all colonoscopy‐recipients during the follow‐up period. Collected data include: socio‐demography, anthropometry, clinical parameters, laboratory investigations, colonoscopy reports, and histopathology. Hospital‐based prevalence estimates and 95% confidence intervals will be calculated and standardized using Poisson distribution. The second study is hospital‐based case‐control study, nested on the cross‐sectional study. Case group will include 150 confirmed CRC cases based on colonoscopy & histopathology. Matched control group will include 300 confirmed non‐CRC participants. Comparative nutritional assessment will be conducted using standardized and validated two‐days Food Record and semi‐quantitative Food Frequency Questionnaire. Data will be analyzed using SHEA software. The third case‐control study will compare the oxidative stress indices among the CRC cases versus Non‐CRC controls. Enzyme colorimetric and flourometric assays will be applied on serum samples to measure selected oxidative biomarkers: glutathione peroxidase, glutathione, glutathoine reductase, catalase, and total antioxidant capacity. High liquid performance chromatography will be used to measure thiol metabolites: SAM, SAH, cysteine, and homocysteine.ResultsA pilot study has been done on 30 CRC cases and 30 controls. Initial results indicated high response rate (88%) and cooperation rate (92%). Data collection tools have been standardized to the local setup (Cronbach's a = 0.07). Pilot assessment indicated high inter‐rater reliability (Pearson's r coefficient= 0.84); and high validity parameters (content, construct & criterion).ConclusionStudy protocol has been designed & validated to conduct CRC prevalence estimation, comparative nutritional & biochemical assessments between CRC and non‐CRC participants among colonoscopy‐recipients in Oman. Initial piloting indicated high applicability of study tools to local context.Support or Funding InformationSultan Qaboos UniversityThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.