Janine Antoinette Quinto (z3422320)
Early-stage breast cancer patients report high stress and possess elevated cortisol levels following surgery (McGregor, & Antoni, 2009; Antonova et al., 2011). Cognitive behavioural stress management (CBSM) was proposed by Michael H. Antoni et al. (2001; 2003) to facilitate post-surgery adaptation for women with early-stage breast cancer. It utilizes principles of cognitive behavioural therapy (CBT) in conjunction with relaxation techniques, within group sessions. In 2011, Antoni et al. found an indirect relationship between the adoption of CBSM skills and reductions in cortisol. This is important because stress stimulates the ...view middle of the document...
muscle relaxation and deep breathing); CBSM; or Health Education control. Each group contained equal numbers of participants receiving one of three contact levels: low (1-hr sessions), medium (2-hr sessions) or high (3-hr sessions). Each session involved having to learn and exercise skills obtained by the treatment, followed by group discussions and support—except in the case of the control group.
Participants from the control attended seminars, held week 5 of the intervention according to designated levels of exposure: low (3-hr seminar), medium (6-hr seminar) and high (2 x 6-hr seminars). Seminars taught how to manage stress and involved general physical education but did not involve the opportunity to exercise skills, nor the support given from group discussions. The purpose of giving seminars instead of standard hospital care was to provide relevant cancer information that could be perceived as useful, thus acting as a placebo. Additionally, the group setting of seminars mirrors the treatment sessions. All participants were given materials reiterating content taught in sessions/seminars.
Reductions in cortisol (μg/dL) were measured from two serum cortisol tests. Based off Antoni et al.’s experiment (2011), a difference of 0.05μg/dL was decided to be of clinical significance. Actual cortisol measurements have not been included since reductions are easier to interpret within analysis. Blood samples were taken before treatment and 6 months after treatment ended, so the second sample was taken approximately 12 months after the first. Pre-treatment scores were subtracted from post-treatment scores, so that negative values reflect reductions in cortisol while positive values signify an increase. Each sample was taken between 4-6pm, because women with early-stage breast cancer show elevated cortisol production (van der Pompe, 1996; Phillips et al., 2008, 2011) and this is when the circadian rhythm of cortisol fluctuates least (Yehuda, 2003).
Planned Analysis & Planned Contrasts
The Bonferroni-t test was the most efficient method to use for this planned, factorial design. The number of planned contrasts (k) was lower than degrees of freedom for the A, B and AB factors. However, the results indicate strong limitations with this test. This will be explained in suggestions for further analysis.
Contrasts on factor A (exposure):
A1 = [-2 1 1]
A2 = [0 -1 1]
According to Antonio (2011), greater cognitive appraisal is correlated with greater reduction in cortisol. It was suggested that exposure to CBSM training, even re-enactment of skills outside of sessions, would result in increased confidence. This was implied by additional measures of self-competency. Thus for the main effect on factor A, contrast A1 answers whether minimal exposure causes a change in how much cortisol is reduced. In comparison, A2 answers whether excessive exposure causes a change in the reduction of cortisol. However, I reason that medium exposure produces the...