Exploring Factors Influencing Prostate Cancer Screening Among Adult Men in Dar-Es Salaam Tanzania: Using the Theory of Planned Behavior

Theoretical Background and research questions/hypothesis:  Prostate Cancer (PCa) is increasingly recognized as a public health problem. Regular screening is recommended to enable early detection and increase the chances for better treatment outcomes.  This study examined factors influencing decisions of whether or not to participate in PCa screening. The results will guide the designing of behavioral strategies and provide baseline for monitoring and evaluation. An extended Theory of Planned Behavior (TPB) incorporating the constructs from the Health Belief Model and Past Behavior (PB) informed the study. Two Hypotheses (H) were proposed: H1: The TPB constructs will explain a significant amount of variance in Behavioral Intention; H2: Perceived Risk (PR) and PB will significantly increase the explanatory power compared to only using the TPB.

Methods and Results (informing the conceptual analysis):  A cross sectional survey involving 164 men aged 45 – 71 years was conducted in Dar-es-Salaam markets from July - August 2015. A questionnaire was used in collecting information about PCa screening knowledge, intention and behavior, and media utilization. A brief TPB questionnaire with PR and PB added was adopted in measuring behavioral intention. Internal consistency for the TPB constructs ranged from Cronbach’s Alpha 0.732 – 0.899. Hierarchical regression analysis was applied in hypothesis testing. P-value of ≤ 0.05 was considered significant. The results show that screening behaviour was reported by only 2 percent, while correct knowledge of PCa risk factors and PCa screening constituted 10.8 and 25.8 percent respectively. The study’s model explained substantial amount of variance (R2 = 0.516, p=0.000) in behavioral intention. The TPB accounted for R2 = 0.513 (p=0.000), supporting H1. The contribution of PR (R2 = 0.010) and PB (R2 = 0.011) was not significant, therefore H2 was not supported. Beta coefficients (β) indicated that only Perceived Behavioral Control (PBC) (β = 0.353, p=0.000) and Subjective Norms (SN) (β = 0.332, p=0.000) predicted intention. The contribution of Attitude (β = 0.003), PR (β = 0.134) and PB (β =0.108) were not significant . Further results show that only 34.4 percent received information from health service providers. The use of any mobile phone and Smartphone were 90.7 and 36.6 percent respectively.

Conclusions:  PCa screening uptake was found to be low, with knowledge being inadequate. The usefulness of the TPB in predicting PCa screening was supported. The emergence of PBC as the most important factor suggests that PCa screening is primarily under the influence of the amount of confidence that individual feel they can perform the behavior. This is determined by perceived self-efficacy and external facilitating and inhibiting factors.

Implications for research and/or practice:  Theory-based behavioral studies provide the required evidence on which factors should be addressed in modifying behaviors. In this study, factors related to personal determination complimented by perceived pressure from important referents can be targeted to increase PCa screening uptake. Interventions should be considered to encourage Health Insurance schemes for market-workers. Introduction of decision-support tools and strengthening the role of health service providers is recommended to improve informed decision-making.  Application of a full TPB model is further recommended to better understand specific control and normative beliefs underlying prostate cancer screening.