Measuring Attitudes toward Participation in Cancer Treatment and Cancer Prevention Trials: The Attitudes toward Cancer Trials Scales (ACTS)

Article excerpt

This investigation aimed to develop psychometric instruments that measure attitudes toward participating in cancer treatment trials (CTs) and cancer prevention trials (CPTs), that is, the Attitudes Toward Cancer Trials Scales (ACTS). A conceptualized construct of attitudes toward CTs and CPTs guided the writing of items for psychometric measurement. An expert panel assessment condensed reduced items to 116, and these were formatted into a self-report written survey. Data collection occurred within multiple settings, targeting an ethnically diverse sample ( N = 312). Item and principal component analyses empirically supported the Attitudes Toward Cancer Trials Scales (ACTS), a 2 -dimensional instrument containing an 18-item CT scale (four components) and a 16-item CPT scale (3 components) with Cronbach's alpha values of .86 and .89, respectively. Four components comprised the CT scale: personal benefits, personal barriers and safety, personal and social value, and trust in the research process. Three components comprised the CPT scale: personal barriers and safety, altruism, and personal value. Early evidence of the internal consistency reliability and construct validity of the ACTS was provided by the sample.

Keywords: attitude measurement; cancer trial participation; cancer prevention trial participation; psychometric instrument development

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Cancer has been revealed as the leading cause of death since 1999 in persons under 85 years of age when death statistics in the United States are aggregated by age (Jemal et al., 2007). Jemal and colleagues reported that cancer caused approximately one in four deaths (23%) in the United States in 2004. Two broad national health strategies for reducing mortality and morbidity from cancer are improving its treatment and preventing its onset. Both strategies rely in part on research carried out to identify and implement new interventions to reduce morbidity and mortality from cancer. Though cancer treatment trials have been supported by the National Cancer Institute (NCI) since its establishment in 1937, cancer prevention trials have become increasingly prevalent, particularly since the designation of the Division of Cancer Prevention and Control in 1983 (Greenwald, 1995).

Cancer prevention trials (CPTs) are analogous to cancer treatment trials (CTs), except that study participants generally have no current diagnosis of cancer and are not seeking cancer treatment. Study participants in CPTs might be former cancer patients, for example, those considered cured of a cancer but at elevated risk for new or recurrent cancer development. CPT participants may be persons at higher-than-average risk for cancer development, such as persons with precancerous cellular lesions. For participants in the intervention group within a CPT, a cancer risk factor may be removed or a cancer prevention intervention may be introduced (Buyse, Autier, & Piedbois, 1992). Over time, the groups are compared for cancer incidence or cancer progression.

As the national emphasis on cancer prevention grows, CPTs are emerging as a valuable tool, and increasingly more health care consumers are being asked to take part in these trials. Because cancer incidence is low, even in populations at high risk, CPTs often require thousands of subjects and must be conducted over several years to achieve sufficient statistical power in study design (Tangrea, 1997). The timely enrollment of participants in these trials is a major concern for researchers.

Enrolling health care consumers in CPTs is a new area of study. Decisions to enroll in CPTs are often shared by consumers and providers. Because CPTs focus on the prevention of cancer, participants are generally healthy volunteers, not patients seeking needed treatments. Cancer professionals, therefore, share a growing multidisciplinary interest in knowing more about how health care consumers make CPT enrollment decisions. …