Research article
Relatives of colorectal cancer patients: Factors associated with screening behavior

https://doi.org/10.1016/S0749-3797(03)00202-2Get rights and content

Abstract

Background

The purpose of this study was to identify whether decisions regarding colorectal cancer (CRC) screening by relatives of CRC patients are influenced by social interactions with family members, friends, and physicians or by public awareness campaigns.

Methods

Screened (n=236) and nonscreened (n=132) relatives of CRC patients were interviewed in 2001. A socioecologic model was used as the framework for the interview variables, which included interactions with relatives, medical professionals, and social groups, as well as perceived benefits and barriers to screening and perceived susceptibility.

Results

Physician encouragement, fewer barriers to screening, strong CRC family history, encouragement from relatives, advice from a surgeon, and discussion of CRC screening with social groups were all associated with ever having been screened. Having been encouraged by a physician was the strongest correlate of screening behavior. Perceived susceptibility to CRC, advice from family members, and exposure to public awareness information were not associated with screening.

Conclusions

The socioecologic framework is a good explanatory model of CRC screening in increased-risk relatives, as variables from each level were associated with screening. These findings can guide interventions aimed at increasing screening uptake, particularly those involving physicians.

Introduction

C olorectal cancer (CRC) is one of the most important health problems in the Western world. In Canada and the United States combined, 165,900 cases of CRC were expected to be diagnosed in 2002, and 63,200 deaths are expected to result from the disease. Colorectal cancer is among the top three leading causes of cancer deaths in Canada and the United States, and the lifetime risk of disease in these two countries is about 6%.1, 2

A family history of CRC increases the risk of colorectal neoplasia, and there is good evidence to support an increased CRC risk among first-degree relatives of CRC patients. The risk increases as the diagnosis age of the proband decreases and as the number of affected family members increases.3, 4, 5, 6 Thus, relatives of CRC patients represent an increased-risk group that might benefit from targeted screening or prevention programs.

Several modalities are available for CRC screening, including fecal occult blood testing (FOBT), sigmoidoscopy, and colonoscopy. Various agencies have published screening guidelines for relatives of CRC patients. Some recommend that relatives of CRC patients follow population screening guidelines but start at an earlier age,7 whereas others specifically recommend colonoscopy, starting at an age that depends on the family history.8, 9 In Canada, the guidelines at the time of this study recommended that patients with one or two first-degree relatives with CRC be screened the same as the general population.10, 11

Few investigations have examined correlates of screening in relatives of CRC patients. Qualitative12, 13 and quantitative14, 15, 16, 17 studies have identified several correlates of CRC screening, with physician recommendation consistently associated with screening behavior.13, 15, 16, 17 The relationship between CRC screening and demographic variables is inconsistent, however, as is the relationship to perceived risk of CRC. To date, studies have not focused on social interactions (such as advice or encouragement) with relatives and social contacts (such as friends and coworkers). Although health beliefs and attitudes toward CRC screening have been emphasized in previous studies, there is a need to examine other variables to improve our understanding of screening behaviors in relatives of CRC patients.

The objective of this study was to examine factors that might influence screening decisions among relatives of CRC patients. This study focused on interactions (advice giving and encouragement) between at-risk relatives and their families, healthcare providers, and social contacts. Using an adaptation of a socioecologic model18 as the theoretic framework, variables were examined at the individual, family, physician, and societal levels of interaction. Although socioecologic frameworks have been used predominantly to design and evaluate health promotion programs, using this model to study CRC screening was appealing because it is complementary to most of the cancer screening research to date.

Section snippets

Accrual of subjects

Subjects were accrued from an existing resource, the Ontario Familial Colon Cancer Registry (OFCCR). Details of OFCCR protocols can be found elsewhere.19 Briefly, the OFCCR identified residents of the province of Ontario, Canada who were diagnosed with CRC between July 1, 1997, and June 30, 2000. Participants were asked to identify eligible relatives (parents, adult children, or siblings of family members with CRC). Relatives were invited by the OFCCR to complete a Personal History

Response rates

As of June 2000, there was a total of 722 potentially eligible participants in the OFCCR database; 115 were excluded (111 were classified as “diagnostic,” 2 were deceased, 1 was diagnosed with CRC, and 1 participated in a CRC-screening trial), leaving 607 eligible subjects. Of those, 565 (93%) responded, and 420 agreed to be interviewed (69.2% of 607). Interviews were completed (from June 2001 to November 2001) with 416 subjects; of these, 48 were either nonresidents of Canada or not a

Discussion

The final model included variables from each level of the socioecologic framework, suggesting that interactions occurring at all levels contribute to CRC-screening decisions. The encouragement of physicians and lack of perceived barriers to colonoscopy demonstrated the strongest associations with screening.

Other studies have associated screening with education15, 17 and gender.14 Increasing age has been associated with screening14, 17; however, because these studies included subjects who had

Conclusions

This is the first study to use a socioecologic model as a framework for exploring CRC-screening decisions. Although all levels of the framework are important and were represented in the final model, some levels (particularly the physician level) may be more influential than others.

Although some of these results are supported by previous studies from other health system settings, others are novel findings and were derived through the use of a theoretic framework that appears to be an excellent

Acknowledgements

Supported by the Canadian Institutes of Health Research grant no. CRT-43821. LM was supported by a doctoral studentship from the National Cancer Institute of Canada with funds from the Canadian Cancer Society. JM was supported as a Scientist of the Canadian Institutes of Health Research. Personal History Questionnaire data collection was supported by the National Cancer Institute, National Institutes of Health, under RFA no. CA-95-011, and through cooperative agreements with members of the

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