A pilot study of a physical activity intervention targeted towards women at increased risk for breast cancer.

Among women, breast cancer is the second leading cause of cancer death[1]. Women with one first degree relative with breast cancer have a two to four times increased risk for developing breast cancer, compared to women with no family history[1]. Although women cannot modify some of their risk factors for breast cancer, including family history and age, other factors can be changed. One such modifiable factor is engaging in regular physical activity. There is mounting evidence of the benefits of physical activity related to reduction of breast cancer risk. Epidemiological research has consistently found an inverse relationship between participation in regular physical activity and breast cancer risk[2–4]. Literature reviews have found that physical activity is associated with, on average, a 20% risk reduction in breast cancer[2–5]. Reviews of the literature support that there is a dose-response relationship for physical activity and breast cancer risk[5, 6]. One review of epidemiological studies that examined the dose-response related to different intensities of physical activity reported a 22% risk reduction for moderate intensity physical activity and 26% risk reduction for vigorous intensity physical activity[6]. Another review[5] examining the dose-response related to time spent engaged in physical activity calculated that for every one-hour of physical activity per week there is an additional 6% breast cancer risk reduction. In addition to the direct benefits of physical activity on breast cancer, physical activity can also reduce adiposity[7–9], which is associated with increased risk of lifetime breast cancer in postmenopausal women [10–13]. Therefore, promoting regular physical activity may be extremely important for women at increased risk for breast cancer. Physical activity may also address some of the psychosocial issues faced by women with a family history of breast cancer. First degree relatives of breast cancer patients have been found to have significant amounts of cancer related and general distress[14–17]. Some studies even suggest that relatives may experience levels of distress that are comparable to patients’ distress[18–20]. However, other studies have found that first degree relatives did not report higher levels of distress than those with no family history of breast cancer[21, 22]. Some of the discrepancies in findings may be related to individual differences, with research suggesting that women who are younger, less educated, and have a higher perceived risk of breast cancer are at increased risk for distress[18, 23, 24]. Physical activity has been shown to decrease psychological distress and increase emotional well-being in non-patient populations[25, 26] as well as cancer patients[27, 28]. Since first-degree relatives of breast cancer patients are at increased risk for psychological distress they may benefit from engaging in physical activity. Although physical activity may reduce risk of breast cancer and psychological distress, women generally do not spontaneously make changes in their physical activity following a diagnosis of breast cancer in a first-degree relative. Therefore, they could benefit from participation in a physical activity intervention designed to increase their physical activity and potentially lower their risk of breast cancer. While physical activity interventions have been developed with a focus on a variety of populations including healthy adults and cancer patients, no interventions to our knowledge have been developed with a focus on first-degree relatives of cancer patients. Although first-degree relatives of breast cancer patients may be healthy themselves, they may have concerns and motivations for engaging in physical activity that differ from those of other healthy adults. These women may benefit from a physical activity intervention that addresses specific concerns about their health related to their increased risk for breast cancer and possible increased distress surrounding their cancer risk or family member’s cancer diagnosis. These women may also not be aware of ways to decrease their breast cancer risk. For example, one study of sisters of breast cancer patients found that these women had lower perceived response efficacy for physical activity than they had for mammography screenings, meaning that they did not believe physical activity would decrease their breast cancer risk or morbidity but did believe that mammography screenings would increase early detection and decrease morbidity. Teaching women about the relationship between physical activity and breast cancer risk may be a motivating factor to engage in physical activity. The Social Cognitive Theory (SCT), a theoretical framework commonly used to explain behavior change, including physical activity, states that behaviors are determined by personal factors, environmental influences, and behavioral attributes, and that behaviors occur within a dynamic interaction between these factors [29–31]. Teaching women about breast cancer risk, and using concerns about breast cancer to motivate behavior can help to influence expectancies (i.e., environmental cues, outcome expectations, and self-efficacy) and incentives (value of the outcome), two major concepts of SCT. If a woman is concerned about getting breast cancer and she feels that being sedentary poses a threat to her risk of getting breast cancer (environmental cues), then she is likely to become more physically activity if she also believes that engaging in physical activity would decrease that threat (outcome expectations), and that she is able to increase her physical activity (self-efficacy)[31]. Therefore, incorporating breast cancer risk information into a physical activity intervention could be influential in promoting behavior change. The current study pilot tested a 12-week theory-based physical activity intervention that was targeted towards women with a first-degree relative with breast cancer. The primary aim was assess changes in physical activity from baseline to the end of the intervention. A secondary aim was to explore the association between breast cancer worry, perceived breast cancer risk, and perceived control over breast cancer risk with reported physical activity.