Best Of Best Poster Oral Clinical Oncology Society of Australia Annual Scientific Meeting 2017

Just as I expected: The impact of pre-treatment response expectancies of radiotherapy toxicities (#136)

Elise J Devlin 1 , Hayley S Whitford 2 , Linley A Denson 1 , Andrew E Potter 3
  1. The University of Adelaide, Adelaide, SOUTH AUSTRALIA, Australia
  2. Division of Health Sciences, Sansom Institute for Health Research, Adelaide, South Australia, Australia
  3. Royal Adelaide Hospital, Adelaide, South Australia, Australia


Research based predominantly on females undergoing chemotherapy, has indicated patients’ pre-treatment response expectancies of treatment side-effects often predicts their subsequent toxicity experience; therefore, screening for high expectancies may identify those requiring additional support. This study investigated the predictive strength of expectancies above and beyond known and unique influences, in a novel, homogenous cohort and treatment modality; men with prostate cancer undergoing a similar dose of radiotherapy.


A longitudinal, within-participant design requiring 30 patients, accrued 35 men with prostate cancer, naïve to external beam radiation therapy (EBRT), who completed baseline measures 4-weeks before commencing 7.5 weeks of weekday treatment. These included study-specific assessments of toxicity expectancies (visual analogue scales; VAS, 0-100), baseline symptoms, demographics, standardised measures of emotional state (Depression Anxiety and Stress Scale 21; DASS21), and coping style (Mental Adjustment to Cancer; MAC Scale). Two-weeks into EBRT, current toxicity experience was assessed alongside future expectancies, relevant to toxicity experience measured again at the 7-week point.


Controlling emotional state, coping style, and demographic/health variables, a series of multiple linear regressions found pre-treatment expectancies uniquely predicted six toxicity experiences (p<0.05) 2-weeks into treatment, contributing 12-39% of explained variance (β=0.39-0.67), despite toxicities not medically expected until approximately 5 weeks into EBRT. Expectancies assessed 2-weeks into treatment uniquely predicted seven toxicities (p<0.05) experienced 7-weeks into EBRT, explaining 23-60% of the variance (β=0.49-0.94). Sexual side-effect expectancies revealed the strongest associations with their experience (β=0.46-0.94; p<0.01), particularly by 7-weeks.


Side-effect expectancies predict patient experience of multiple toxicities throughout EBRT. Controlling multiple influences, expectancies of sexual side-effects have the strongest effect on experience across radiotherapy for men. Although medically expected in EBRT, findings suggest psychosomatic influence given early associations in treatment for six side-effects. Sexual and other prominent toxicities require a substantial focus on psychological intervention in practice and further replication.