Inclusion Criteria for prostate cancer patients:
* Written infor med consent according to International Conference on Harmonisation (ICH)/Good Clinical Practice (GCP) regulations before registration and prior to any trial specific procedures
* Histologically proven adenocarcinoma of the prostate
* Eastern Cooperative Oncology Group performance status 0-2
* Adult male patient \> 18 years of age, no upper age limit
* Localized prostate cancer, locally advanced hormone-sensitive prostate cancer (HSPC) or metastatic hormone-sensitive prostate cancer (mHSPC)
* ADT recipients are required to be scheduled to start ADT as standard of care (SOC) for metastatic or locally advanced prostate cancer
* Scheduled to receive ADT treatment as SOC for \> 6 months in combination with radiotherapy or oral AR-targeted systemic treatment as prescribed by the treating physician or radiotherapy alone
Exclusion Criteria for prostate cancer patients:
* Histology with predominant small cell prostate cancer
* Any previous treatment with ADT or oral AR-targeted agent (exception for short course anti-androgens - disease flare)
* Have not received systemic treatment for any other cancer within the last 12 months
* Active secondary malignancy that requires systemic therapy
* Any clear contraindications present against treatment with ADT
* Presence of sleep apnea syndrome, Apnea Hypopnea Index (AHI) \>15 at baseline
* Body mass index (BMI) \> 35 at baseline
* Severe respiratory disorders (asthma, Chronic obstructive pulmonary disease) at baseline
* Severe cardiovascular disease or severe cardiovascular event \< 6 months
* History of stroke or other neurologic chronic illnesses \< 6 months
* Have demonstrated impaired mental status
* History of brain tumours, presence of brain metastases or previous cranial irradiation
* Night shift workers
* Excessive lifestyle: massive coffee intake at night, regular excessive cigarette and alcohol consumption in the evening
* Unhealthy sleep hygiene
* Nocturia (the urgent need to urinate more than 2 times during the main sleep period at night) at baseline
* Present diagnosis of depression or psychiatric illness pharmacologically treated
* Diagnosis of insomnia and chronic intake of hypnotic medication at baseline
* Chronic intake of medications that are known to induce sleep disturbance (antihistamines of first generation, cortisone intake \> 25 mg/day)
* Any diagnosed condition that causes known sleep disturbance
Inclusion criteria for breast cancer patients
* Written informed consent according to International Conference on Harmonisation (ICH)/Good Clinical Practice (GCP) regulations before registration and prior to any trial specific procedures
* Women with full-resected early (stage I-III) epithelial BC, ductal carcinoma in situ or lobular carcinoma in situ, without evidence of residual disease
* Eastern Cooperative Oncology Group performance status 0-2
* Adult female patient ≥ 18 years of age, no upper age limit
* Proven postmenopausal status (defined by absence of menstruation for at least 6 months and/or level of estradiol \<40 pg/ml, or bilateral oophorectomy or ovarian irradiation for suppression of ovarian function)
Exclusion criteria for breast cancer patients
* Non-epithelial BC or BC with mixed epithelial and non-epithelial histology
* Previous chemotherapy at any time, in treatment with ET at not standard dosage
* Have received systemic treatment for any other cancer within the last 12 months
* Active secondary malignancy that requires systemic therapy
* Presence of sleep apnea syndrome, Apnea Hypopnea Index (AHI) \>15 at baseline
* Body mass index (BMI) \> 35 at baseline
* Severe respiratory disorders (asthma, Chronic obstructive pulmonary disease) at baseline
* Severe cardiovascular disease or severe cardiovascular event \< 6 months
* History of stroke or other neurologic chronic illnesses \< 6 months
* Have demonstrated impaired mental status
* History of brain tumours, presence of brain metastases or previous cranial irradiation
* Night shift workers
* Excessive lifestyle: massive coffee intake at night, regular excessive cigarette and alcohol consumption in the evening
* Unhealthy sleep hygiene
* Nocturia (the urgent need to urinate more than 2 times during the main sleep period at night) at baseline
* Present diagnosis of depression or psychiatric illness pharmacologically treated
* Diagnosis of insomnia and chronic intake of hypnotic medication at baseline
* Chronic intake of medications that are known to induce sleep disturbance (antihistamines of first generation, cortisone intake \> 25 mg/day) or any diagnosed condition that causes known sleep disturbance