Blood test may predict brain fog from prostate cancer treatment

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: Patient Participants- * Age 18 years or greater. * Fluent in reading, listening to, and writing English. * Current or prior diagnosis of prostate adenocarcinoma based on a pathology report or as documented in a medical oncology, urology, or radiation oncology note. * Access and ability to use a computer or mobile device with Internet connectivity to complete study procedures. * Telephone Montreal Cognitive Assessment (T-MoCA) of 16 or greater. * Eastern Cooperative Oncology Group (ECOG) performance status 0-2 (documented within past 3 months, otherwise patient-reported). Study partner participants- * Age 18 years or greater * Fluent in reading, listening to, and writing English * Identified by patient participant as a person who knows patient participant well, like a friend, family member or spouse. * Access and ability to use a computer or mobile device with internet connectivity to complete study procedures. Only the ADT cohort- * Anticipated to start ADT, which includes one of the following two treatments * Gonadotropin-releasing hormone (GnRH) agonist (e.g., leuprolide, goserelin, and others). * GnRH antagonist (i.e., degarelix or relugolix). * Anticipated to remain on ADT for at least 12 months. * Concurrent first-generation anti-androgens (e.g., bicalutamide, flutamide, nilutamide) and novel androgen-signaling inhibitors (e.g., abiraterone, enzalutamide, and apalutamide) are allowed. * Concurrent radiation is allowed. Only the PC cohort- * Has completed definitive local therapy (radical prostatectomy or radiation therapy) for localized prostate cancer at least 6 months prior to screening. * For radical prostatectomy: undetectable prostate-specific antigen (PSA) within 12 months of screening. * For radiation therapy: last PSA of \< 2.0 within 12 months of screening. Exclusion Criteria: Patient Participants- * Small cell prostate carcinoma (pure or mixed). * Receipt of ADT (GnRH agonist, GnRH antagonist, 1st-generation anti-androgen, or novel androgen signaling inhibitor) within 6 months before screening. ADT \>6 months prior to screening is allowed provided testosterone has recovered to 100 ng/ml or greater. * Concurrent or anticipated (at any point during first 12 months of ADT) non-hormonal, antineoplastic systemic therapy, such as chemotherapy. * Testosterone \<100 ng/ml. * Prior or concurrent brain metastases (no prior or screening imaging is required). * Major neurocognitive or psychiatric disorders, such as dementia or schizophrenia. * Prior or concurrent malignancy other than prostate cancer whose natural history or treatment has the potential to interfere with study assessments. Study partner participants- * None. Only the ADT cohort- * None. Only the PC cohort- * Any prior, concurrent, or anticipated use of any hormonal systemic therapy, including GnRH agonist, GnRH antagonist, 1st-generation anti-androgen, or novel androgen signaling inhibitor. * Any known or prior history of M1 prostate cancer (no screening imaging required). * Current or prior biochemical recurrence following American Urological Association guidelines for radical prostatectomy or American Society for Therapeutic Radiology and Oncology (ASTRO) guidelines for radiation therapy.