In this prospective study evaluating sleep quality in chemotherapy naïve women undergoing treatment for breast, ovarian, or endometrial cancer, the majority of our sample reported poor sleep quality after diagnosis and prior to initiating treatment. Moreover, sleep disturbance rates increased after starting chemotherapy and remained elevated up to 6 months post-treatment.
The rates of sleep disturbance in our study are comparable to prior work. Westin et al. reported sleep disturbance in 54.9% of gynecologic cancer survivors [21].. While Clevenger et al found that 70% of women with OC had disturbed global sleep (PSQI > 5) with 24% severe enough to be considered clinically impaired (PSQI ≥ 10) at baseline [17]. Another study found that 25% of patients with EC experienced poor sleep quality at diagnosis, however after receiving systemic treatment, 86% reported poor sleep quality at treatment completion [16]. Sleep disturbances have also been described among BC patients with one study showing poor sleep quality in > 60% of patients at baseline and during chemotherapy while 38% of 5-year BC survivors reported experiencing sleep problems [12, 20]. Our study is novel in that we examined associations between disturbed sleep and overall quality of life, compared sleep disturbances between women with different types of malignancies, and assessed sleep quality at multiple points across the course of chemotherapy.
The reasons for sleep disturbance in gynecologic malignancies remain poorly understood. Cancer patients repeatedly endure multiple overlapping and interacting physical and emotional events that likely play a mechanistic role but are difficult to disentangle. The comparison of BC and GynCa patients, in this study, may provide insight into a contributing factor in sleep disturbance. The BC patients in our study were significantly younger than their GynCa counterparts and therefore, more likely to be pre- or peri-menopausal at the time of diagnosis. Menopausal symptoms, such as hot flashes, have been found to be associated with less efficient and more disrupted sleep [22, 23]. While menopausal status was ascertained in this study, menopausal symptoms were not. This could, in part, explain why a higher percentage of patients in the BC group reported poor sleep quality both at baseline (BC: 64%, GynCa: 53%) and 6 months post-treatment (BC: 63%, GynCa: 46%).
Our quality-of-life results findings provide another example of the complexity of pinpointing the factors that underlie sleep disturbance. At baseline FACT-G scores of both GynCa and BC participants were comparable to reference values for adult cancer patients [23]. At 6-months post treatment, however, we saw improved FACT-G scores compared to baseline among our GynCa patients but not among our BC patients. We speculate that there could be an interaction between improvement in symptomatic disease burden- seen frequently in advanced stage OC and EC patients at initial diagnosis- and worsening vasomotor symptoms in the BC group over the course of treatment. Future research examining the mechanisms contributing to poor sleep among women with gynecologic cancers would benefit from more fine-grained assessments of known contributing factors, i.e., longitudinal collection of contemporaneous menopausal symptoms across chemotherapy.
Strengths of our study are the high enrollment and retention rates − 97% of women approached agreed to participate in the study, 95% were eligible, and 97% of those who enrolled participated at all 4 time points and the overall questionnaire completion rate was 80%– supporting the feasibility and acceptability of this study design. Limitations of this study include the heterogeneity of cancer diagnoses and the homogeneity of the study sample with respect to demographic factors that are considered social determinants of health. Future work examining sleep in women with gynecologic cancers should include a more diverse sample, as racial and ethnic health disparities have been described both in cancer and in sleep health [24].
Although poor sleep quality was associated with lower QOL at most study time points in both the GynCa and BC patients, it is important to note that we cannot determine a causal relationship. What is known from the literature is that patients with worse health related QOL have poorer survival across a variety of malignancies [25–27]. The assessment and identification of strategies to deal with sleep disturbance are of paramount importance since poor sleep quality represents a potentially modifiable factor that, could be targeted to improve QOL and subsequently impact cancer prognosis in a group of malignancies that almost exclusively affect women. An interesting finding from this study is the baseline to mid-treatment period where both sleep quality and QOL worsened significantly in both groups. This has not been reported in other studies and represents a time point of interest.
This is one of the few studies to examine subjective sleep quality during chemotherapy longitudinally among women with OC and EC. It is also one of the few to compare BC and GynCa. The design is replicable and future studies should aim to answer this question in a larger, more heterogeneous study population. The PSQI is easily administered and has a sensitivity of 90% and a specificity of 87% making it an appropriate tool for evaluation [18]. Future studies using tools like actigraphy, sleep diaries, and polysomnography would provide objective sleep data to complement the PSQI while measurement of hormonal biomarkers (e.g., FSH, LH, cortisol) could help specify possible mechanisms through which sleep quality is negatively impacted.