Colorectal cancer (CRC) is the fourth most commonly diagnosed cancer and the second leading cause of cancer deaths in the United States (1
). Lifetime risk for CRC is approximately 5% after age 50. Individuals with a first-degree relative (FDR; sibling, parent, child) diagnosed with CRC have an estimated lifetime CRC risk of 10% (2
). The risk increases as the age of the proband at diagnosis decreases (5
) with estimates ranging between two and four times the average risk (3
Screening results in earlier detection of CRC and reduces disease-specific mortality (7
). Various agencies have published screening guidelines for relatives of CRC patients. A number of professional organizations recommend that FDRs should follow population screening guidelines but begin CRC screening (CRCS) at a younger age than general guidelines with recommended screening starting at age 40 (9
). Others specifically recommend colonoscopy starting at an age that depends on the family history (1
). Estimates of CRCS among family members at increased risk for CRC have varied widely with reported rates of 22% (10
), 39% (11
), 55% (12
), 64% (13
) and 79% (14
), depending upon the screening procedure examined and the targeted at-risk population.
Given the increased risk for CRC among FDRs of individuals diagnosed with CRC and the relatively low participation in this at-risk population, effective methods of increasing CRCS participation are needed. Unfortunately, the few behavioral interventions targeting this at-risk population have shown limited impact on screening adherence. Glanz and colleagues (15
) evaluated the impact of an individual face-to-face health counseling intervention that was accompanied by tailored print material and two follow-up phone calls compared with a general health counseling intervention among FDRs of CRC patients. Results indicated that the counseling intervention increased screening significantly among non-adherent participants compared with the general health counseling. Rawl and colleagues (16
) compared the efficacy of a tailored print intervention versus a non-tailored print intervention on CRCS among FDRs of CRC patients. While both interventions resulted in increased CRCS, CRCS rates did not differ between the study groups nor were there differences in forward progression in stage of adoption of CRCS.
The primary aim of this study was to evaluate the effect of three increasingly intense behavioral interventions on CRCS adherence among FDRs of individuals diagnosed with CRC before the age of 61 years who were not on-schedule with regard to CRCS. We compared a generic print intervention (GP), a tailored print intervention (TP), and a tailored print and telephone counseling intervention (TP + TC). We hypothesized that the greatest CRCS would be among individuals participating in the TP + TC intervention followed by individuals enrolled in the TP intervention. The lowest CRCS adherence was predicted in the GP intervention because it would lead to messages that were not perceived as directly relevant to the individual. In contrast, by tailoring materials superfluous information would be eliminated. The remaining tailored information would be considered more personally relevant and receive greater attention and, thus, would be more likely to have an effect (17
). A recent meta-analysis of tailored interventions indicated that tailored messages are more effective in triggering behavioral change than generic messages (18
) and recent work has suggested that tailored messages result in significant effects on CRCS among average risk individuals (19
Because tailoring is not in itself a theoretical or conceptual framework, we drew on established health behavior theories as well as the constructs shown to be associated with screening adherence for guidance concerning which variables to use as the basis for developing tailored messages. In our prior work (12
), we integrated constructs from three conceptual models: the Health Belief Model (HBM) (20
), the Transtheoretical Model (TTM; 23
), and the Dual Process Theory (25
). The models are largely complementary and there is considerable overlap among them. For the present study, tailoring for both the print and telephone counseling was based upon the following constructs from these models that we found to be associated with CRCS adherence and intention in the targeted population in our previous work (12
): pros of CRCS, cons of CRCS, processes of change (i.e., commitment to CRCS), stage of adoption, perceived CRC preventability, perceived CRC risk, physician and family support for CRCS, the closeness of the relationship with the affected sibling, medical insurance status, and knowledge of CRC and CRCS.
The secondary aim was to evaluate possible moderators and mediators for intervention effects. Behavioral interventions may not be beneficial for all participants and thus it is important to identify subgroups of persons who are particularly amenable or resistant to the effect of each intervention. Ultimately, this will provide more effective and possibly cost-effective interventions for those who will benefit most. Intervention moderators were selected based upon factors predictive of response to other cancer screening interventions such as mammography (27
). Moderators evaluated included previous CRCS history, the number of family members with CRC, whether the participant had received a physician recommendation for CRCS at the baseline interview, baseline screening intention, and the closeness of the participant’s relationship to the affected sibling.
Although accumulating evidence indicates that CRCS interventions show efficacy in improving CRCS adherence, little is known about why these interventions work; that is, we have not identified the mediators of intervention effects. An understanding of why these interventions work will guide the development of more effective screening interventions as well as provide support for theories guiding these interventions. We selected potential mechanisms of change based upon HBM, TPB, and Dual Process Theory constructs that were targeted in the tailored interventions. Mediators evaluated included CRC knowledge, CRCS knowledge, physician support for CRCS, family support for CRCS, perceived CRC risk, perceived CRC severity, perceived CRC preventability, four processes of change, decisional balance, and personalization of the print materials.
In the present study, we targeted siblings of individuals diagnosed with CRC prior to the age of 61 years for intervention rather than patients’ children or parents. The age range of children would likely be too young to meet screening guidelines and the parents of these individuals may no longer be alive.