RESUMEN
INTRODUCTION: Early detection of cancer is a highly effective way to decrease cancer-related deaths. The purpose of this study was to determine the disparity in cognitive factors related to cancer screening uptake based on the theory of planned behavior (TPB). METHODS: In this cross-sectional study, conducted in Kermanshah County, the west of Iran, during 2019, a total of 1760 people aged 30 to 75 years old, were randomly selected to participate voluntarily in the study. Participants filled out a questionnaire including the socio demographic variables, socioeconomic status (SES), TPB variables, and cancer screening uptake behaviors. RESULTS: The mean age of respondents was 45.28. 44.96% of the participants had undergone cancer screening at least once. Socioeconomic status (SES) and gender had the most significant impact on the disparity in cancer screening uptake, with contributions of 74.64% and 22.25% respectively. Women were 8.63 times more likely to be screened than men. Participants with a family history of cancer had a 2.84 times higher chance of being screened. Single individuals were significantly less likely to be screened compared to married individuals. The concentration index for attitude, subjective norms (SN), perceived behavior control (PBC), behavior intention, and cancer screening uptake was 0.0735, 0.113, 0.333, 0.067, and 0.132 respectively. Intention (Beta = 0.225 and P: < 0.001) is a significant predictor of cancer screening behaviors. CONCLUSION: The findings of this study are highly valuable for health policymakers in Iran. They emphasize the significance of creating, executing, and assessing campaigns that promote intention, PBC and SN, particularly among disadvantaged individuals. By doing so, we can effectively decrease the disparity in cancer screening rates. It is crucial to prioritize men, single individuals, and disadvantaged groups in cancer screening promotion programs. This knowledge can be utilized to develop an intervention that is guided by theory and supported by evidence, with the aim of increasing cancer screening rates and minimizing disparities.