Evaluating the relationship between insomnia, vasomotor symptoms and nocturia in patients receiving androgen deprivation therapy for prostate cancer: Results from a single centre observational study.

e17118 Background: Insomnia in prostate cancer patients is common especially in those receiving androgen deprivation therapy (ADT) which can impact daytime functioning and quality of life. The main drivers for insomnia have focused predominantly on either hot flushes and night sweats (HFNS) or nocturia. This study aimed to compare sleep disturbances between ADT and treatment naïve patients, and to evaluate the relative contribution of nocturia, HFNS and other ADT vasomotor symptoms to insomnia. Methods: This cross-sectional, observational study evaluated prostate cancer patients attending an oncology clinic utilised Insomnia Severity Score (ISI), Pittsburgh Quality Sleep Index (PSQI), and Epworth Sleepiness Scale (ESS), and Vasomotor Assessment Score (VAS) to assess sleep quality and vasomotor symptoms for those on ADT and who were on PSA surveillance. Results: Of the150 patients enrolled in the study, 122 completed datasets were available for analysis. 90 were receiving ADT and 32 were ADT-naïve. Those on ADT experienced greater insomnia (mean ISI score 7.04 vs 4.38, p=0.04) and poorer night-time sleep (mean PSQI 6.50 vs 9.64, p= 0.035), with a non-significant trend to increase daytime sleepiness (mean ESS 3.96 vs 2.85, p=0.204). HFNS were significantly more prevalent in the ADT-treated group (p < 0.001) with 67.4% of patients experiencing mild-to-severe symptoms on the VAS. Regression analysis showed that nocturia (p= 0.003), HNFS severity (p=0.004), self-reported low mood (p=0.03) and palpitations (p= 0.003) were independent predictors of insomnia. Medical co-morbidities, ethnicity, alcohol consumption and Body Mass index were not found to be predictive of insomnia in this study. Conclusions: This study has demonstrated that prostate cancer patients on ADT subjectively experience more sleep disturbances compared to ADT-naive patients. It also has reaffirmed the correlation between HFNS, nocturia and insomnia. However, other factors such as low mood and palpitations were also shown to contribute to sleep disturbances, suggesting a complex interplay of ADT and disease related contributors to insomnia. Although both groups experienced sleep disturbances, as indicated by abnormal PSQI scores, insomnia scores were below the clinical threshold, creating a grey area where hypnotics may not be indicated. Consequently, targeting the underlying causative factors such as nocturia, and low mood with specific treatments or utilising a different class of ADT with less associated vasomotor symptoms such as oestrogen patches could allow for a more effective approach to improving sleep quality in these patients. Future studies should explore strategies to address the underlying causes of insomnia in patients receiving ADT to improve treatment compliance and prostate cancer survivorship.