Comparative Analysis of Immunological Responses to Vitamin D Replacement Therapy in Black and West African Men Diagnosed With Prostate Cancer: Elucidating Differential Effects on Immune Function Between Patients With Localized Disease and Those With Metastatic Progression

This study is testing whether fixing vitamin D deficiency in Black/West African men with prostate cancer can strengthen their immune system, improve quality of life, and even slow cancer progression compared to those who remain deficient. Key ideas being tested: 1. More than half of Black/West African prostate cancer patients don't have enough vitamin D. 2. Low vitamin D weakens immune cell function and affects quality of life, but these problems improve after 8 weeks of vitamin D supplements. 3. Immune cell function differs between patients with advanced/recurrent prostate cancer and those with localized disease. 4. Patients with advanced disease who show stronger immune responses after vitamin D correction may live longer without their PSA levels rising (a marker of cancer progression). 5. Immune cell function in Black/West African patients is different from that in Black/African American patients, and this will be checked by comparing data with a parallel Mayo Clinic study. Overall goals: 1 . Measure how widespread vitamin D deficiency is in Black/West African prostate cancer patients. 2\. Understand how vitamin D levels affect immunity and quality of life. 3. Compare immune function between different groups (localized vs. advanced disease, West African vs. African American patients). 4 . See if vitamin D replacement improves both patient well-being and cancer outcomes. Study Flow 1\. Recruitment \& Consent: Patients with prostate cancer (localized or advanced) are invited and give written consent. 2 . Initial Blood Test (10 mL): Check vitamin D and calcium levels. 3. Eligibility: If vitamin D is low (\<30 ng/mL), patients join the treatment phase. 4\. Baseline Testing (50 mL blood + QOL survey): Immune function measured; quality of life survey completed; virtual doctor consult. 5\. Treatment (8 weeks): Daily vitamin D3 pills (2000 IU, free); patients keep a medication diary. 6\. Midpoint Check (Week 4): Phone call to check side effects and compliance. 7 .End of Treatment (Week 8): Repeat blood tests (60 mL), second QOL survey, virtual consult. 8\. Follow up (up to 3 years). Annual phone calls and medical record review to track progression-free survival. In short, the study is trying to show that vitamin D deficiency is common in Black/West African prostate cancer patients, that it harms immune function and quality of life, and that correcting it could improve both health and cancer survival.

Sex

Male

Minimum age

18 Years

Inclusion Criteria:

* Self-identified Black/West African Males, Age ≥18 years
* Patients with a previous history of localized or metastatic or locally recurrent prostate cancer
* Willing to travel to the University of Ilorin Surgery Outpatient Department (SOPD UITH)for baseline and 8 weeks visit for blood collection, if eligible.

Exclusion Criteria:

* Known hypersensitivity to vitamin D.
* End-stage renal failure on dialysis
* Liver cirrhosis
* Currently taking a vitamin D or multivitamin supplement, which has more than 400 IU/10mcg of vitamin D daily for the past month.
* Legal inability or restricted legal ability, medical or psychological conditions not allowing proper study completion or informed consent signature.
* History of hypercalcemia

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