Prevalence and Severity of Sleep Disturbances among Patients with Early Breast Cancer

INTRODUCTION

The diagnosis of cancer and its treatment are associated with high levels of psychological distress. Insomnia is defined as the difficulty to initiate or maintain sleep for at least 1 month causing clinically significant distress and/or social and occupational impairment.[1] Insomnia is aggravated by cancer treatments and their side effects, and therefore should be proactively managed.[2] The burden of insomnia is multifaceted and affects several aspects of patient's quality of life. Patients suffering from insomnia are prone to fatigue, mood disturbances, poor performance at work, and dependence on sleeping pills.[3] The study of insomnia sheds light on an important underrecognized aspect of suffering among cancer patients.[4] In a Middle-Eastern society, the diagnosis of cancer remains a taboo and cancer patients are prone to an amplified burden of psychological distress associated with cancer diagnosis.[56] Breast cancer is the most common cancer diagnosis among women in the Middle East.[7] With a median age of diagnosis of 50 years, breast cancer affects both younger and older segments of the population in Lebanon. Data regarding insomnia or health-related quality of life in breast cancer patients in the Middle East are scarce. Two cross-sectional studies from Bahrain and Jordan have shown that fatigue and sleep disturbances are the most distressing symptoms reported by women treated for early breast cancer.[89] Another cross-sectional study from Jordan showed that fatigue was among the most distressing symptoms in female cancer patients receiving chemotherapy.[10] The aim of this study was to examine the prevalence and incidence of insomnia in early stage breast cancer patients.

PATIENTS AND METHODS

RESULTS

Patient characteristics

Fifty-two patients participated in the study; four patients did not complete the three-point interviews required by the study protocol and were subsequently excluded from the final analysis. The mean age of patients was 50.8 years (range: 26–76 years) [Table 1]. About 62.5% of the patients were unemployed while 31.3% were full-time employed and 4% were part-time employed. The majority of patients were married (77.1%). Half the patients (50.0%) had less than a high school diploma as their highest level of formal education. The majority of patients (93.8%) were diagnosed within 6 months of study enrollment. About 45.8% of patients were treated with adriamycin and cyclophosphamide, 18.8% with 5-fluorouracil, epirubicin, and cyclophosphamide, 18.8% with TC (docetaxel and cyclophosphamide), and 2.1% with other regimens.

Table 1 Patient characteristics

Insomnia scores

Using the PSQI, the prevalence of poor quality sleep was 36.4% at baseline before starting chemotherapy and increased to 58.3% during treatment. It decreased to 32.1% (below the baseline level) 1 month after the end of chemotherapy. The mean PSQI scores mid-treatment and after treatment were significantly different from the baseline values (P < 0.05): 4.96 ± 3.82 at baseline, 7.81 ± 5.10 during chemotherapy, and 3.78 ± 3.81 after treatment [Table 2].

Table 2 Quality of sleep prior to, during, and following chemotherapy, according to the Pittsburgh Sleep Quality Index

According to the ISI scores, the prevalence of clinical insomnia among patients increased from 11.1% before starting chemotherapy to 36.1% during treatment. Consistently with the PSQI results, the prevalence of clinical insomnia dropped back to 6.3% one month after finishing chemotherapy in this cohort. The mean ISI scores followed a similar pattern to the PSQI scores with statistically significant deviation from baseline values (P < 0.05): 0.40 ± 0.75 at baseline, 1.06 ± 1.12 during treatment, and 0.28 ± 0.58 following completion of therapy [Table 3].

Table 3 Prevalence of insomnia at prior to, during, and following chemotherapy, according to the Insomnia Severity Index

DISCUSSION

Our study showed a significant increase in sleep disturbance in early breast cancer patients on chemotherapy and that subsequently improved to below baseline levels on completion of therapy. Prior to chemotherapy, 36% of patients reported poor sleep, and during chemotherapy, the prevalence rose to 58%. The percentage of patients reporting clinical insomnia increased from 11% pretreatment to 36% during chemotherapy reflecting a significant symptomatic burden that is poorly documented and managed in routine clinical practice. The median age of patients in our cohort was 50.8 years, consistent with previous data from the region.[7]

Our results are consistent with the previous studies where higher levels of sleep disturbance have been observed in women undergoing chemotherapy.[91314151617] However, a recent longitudinal study carried out in North America found a higher prevalence of sleep disturbance among female patients undergoing adjuvant chemotherapy for breast cancer: 48.5%–65.8% of patients had PSQI scores ≥5.[18]

In the Middle East, a cross-sectional study of breast cancer survivors in Bahrain reported significant sleep disturbances in 17.6% of women, ranking second after fatigue as the most distressing symptom assessed.[8] Similar results were obtained in a study from Jordan where 13.5% of breast cancer survivors reported clinically significant sleep disturbance, ranking second after fatigue.[9]

Our study is the first prospective study in the Middle East to assess sleep quality and the incidence of clinical insomnia in early-stage breast cancer patients using validated tools. Limitations include the small sample size and lack of additional measures such as the health-related quality of life (HRQOL). In another study, HRQOL measured by the Functional Assessment of Cancer Therapy-General (FACT-G) questionnaire was found to be negatively correlated with global PSQI scores at each time point.[18] Despite these limitations, even in this relatively small cohort of women, chemotherapy treatment was shown to be associated with a significant increase in clinically significant insomnia.

Sleep disturbances in patients with breast cancer undergoing treatment are multifactorial. The direct psychological impact of the disease, cytotoxic chemotherapy, and concurrent medications such as corticosteroids have all been reported as potential contributors.[19] A systematic review of sleep disorders in cancer patients concluded that the prevalence of particular types of sleep disorders in cancer patients is difficult to assess, this is likely due to the primary focus on studying symptoms of poor sleep and not characterizing the underlying sleep disorders in cancer patients and survivors.[20] Thus, identification of the causative factor (s) behind sleep disturbances is crucial to treat insomnia. Psychological interventions, particularly cognitive behavioral therapy, have been of clinical benefit to insomnia patients in randomized clinical trials.[21] However, access to these psychological therapies is currently limited in our region. Yoga has shown improvement in insomnia symptoms among patients with cancer.[22] Acupuncture can also effectively reduce malignant-related depression, improve sleep quality, and help to improve the quality of life of cancer patients.[2324]

CONCLUSIONS

We have shown that patients with non-metastatic breast cancer experience an increase in insomnia and sleep disturbances during the treatment phase. Physicians should be aware of the need to routinely screen for sleep disturbance in breast cancer patients undergoing chemotherapy, with the purpose of minimizing the disease burden on the patients as early as possible. Further studies are required to develop novel strategies for prevention and treatment of insomnia amongst breast cancer patients.