A 2023 study published in the journal Cancer (American Cancer Society) examined vitamin D status in 200 patients with advanced (locally advanced, inoperable, or metastatic) melanoma receiving first-line anti–PD-1 immunotherapy (nivolumab or pembrolizumab). Researchers from Poland found that patients who maintained normal serum vitamin D levels — either naturally at baseline or through supplementation — experienced meaningfully better treatment outcomes than those with persistently low levels.
Key Findings from the Study
Objective response rate (ORR): 56.0% in the normal vitamin D group (complete or partial response) versus 36.2% in the low vitamin D group (p = 0.011).
Progression-free survival (PFS): Median 11.25 months with normal levels versus 5.75 months with low levels (p = 0.038). At 12 months, 48.4% were progression-free in the normal group vs. 34% in the low group.
Overall survival (OS): A non-significant trend favouring normal levels (median 31.5 vs. 27 months; p = 0.39).
Vitamin D deficiency was common at baseline (roughly 75-85% of patients), consistent with broader population trends, especially in regions with limited sun exposure.
The study was partly retrospective and partly prospective. From mid-2018 onward, patients received supplementation (typically 2,000 IU prophylactic or 4,000–6,000 IU to correct deficiency until levels exceeded 30 ng/mL, then maintenance). Supplementation successfully normalised levels in nearly all cases without increasing serious adverse events. Multivariate analysis confirmed low vitamin D as an independent risk factor for faster progression (hazard ratio around 0.65–0.69 favouring normal levels).
Vitamin D appears to support anti-tumor immunity, potentially by enhancing tumour-infiltrating lymphocytes, modulating inflammation, and improving CD8+ T-cell activity — mechanisms that could synergize with checkpoint inhibitors like anti-PD-1 drugs.
Broader Context on Vitamin D and Skin Cancer
Observational data often link higher vitamin D levels (or supplementation) to:
Thinner melanomas at diagnosis (lower Breslow thickness).
Better prognostic features (less ulceration, lower mitotic rate).
Improved survival metrics in some cohorts.
Some studies suggest regular vitamin D supplement users have lower melanoma incidence compared to non-users. However, results are mixed. A 2024 randomised trial of high-dose vitamin D in stage II melanoma patients found it safely raised levels but did not improve relapse-free survival. Dietary or supplemental intake studies sometimes show neutral or even weakly positive associations with non-melanoma skin cancers (basal/squamous cell), likely because higher vitamin D can correlate with greater lifetime UV exposure — the primary driver of most skin cancers.
The relationship is complex: UVB radiation generates vitamin D in the skin but is also the main cause of DNA damage leading to melanoma and non-melanoma skin cancers. Strict sun avoidance (standard advice post-diagnosis) can worsen deficiency, creating a potential trade-off. The Cancer study supports correcting deficiency via supplements rather than deliberate sun exposure, especially for patients already diagnosed.
From a biblical worldview that affirms the goodness of creation (Genesis 1), the body as fearfully and wonderfully made (Psalm 139:14), and human responsibility for wise stewardship, this research highlights practical wisdom in caring for health without idolatry of either "natural" cures or pharmaceutical over-reliance.
Creation order and provision: God designed the human body with intricate systems, including immune regulation influenced by vitamin D — a prohormone with pleiotropic effects. Low levels are common in modern indoor lifestyles, far removed from ancestral patterns of balanced sun exposure. Correcting deficiency aligns with prudent care for the temple of the Holy Spirit (1 Corinthians 6:19-20), especially when evidence suggests it may support the body's fight against disease during medical treatment.
Limits of science and caution: While the 2023 findings are encouraging as an adjunct to proven immunotherapy (not a replacement), they do not prove causation, and not all trials show clear benefits for prevention or relapse. Overhyping supplements risks the "health and wealth" distortion seen in some circles. Christians should prioritise evidence-based medicine, consult physicians for blood testing (aiming for sufficiency, often >30 ng/mL), and avoid extremes — neither scorning God's provision through nutrition/sun nor chasing panaceas that distract from ultimate hope in Christ, the Great Physician.
Cultural critique: Modern public health messaging heavily emphasizes sun avoidance to prevent skin cancer, yet widespread vitamin D deficiency may carry its own costs, including potentially worse cancer outcomes. This echoes broader tensions where well-intentioned policies (or fear-driven narratives) can have unintended consequences. True wisdom discerns balance: protect skin reasonably (clothing, shade, limited midday exposure), test levels when appropriate, and supplement under guidance rather than self-medicating at extreme doses.
Holistic view: Melanoma and other cancers remind us of a fallen world where bodies break down (Romans 8:20-23). While pursuing better outcomes through lifestyle and medicine is good, believers find ultimate peace not in optimised lab numbers but in the resurrection hope (1 Corinthians 15). Prayer for healing, wisdom for doctors, and compassion for the suffering remain central.
For patients with advanced melanoma on immunotherapy, maintaining adequate vitamin D levels appears to be a low-cost, low-risk step that may meaningfully improve response rates and delay progression. Routine testing and targeted supplementation (not blanket high dosing) make sense, especially given high deficiency rates.
For general skin cancer prevention, focus remains on proven measures: UV protection, regular skin checks, and avoiding sunburns. Vitamin D optimisation supports overall health but should not encourage reckless sun exposure.
This line of research underscores that nutrition and immune support matter in oncology. Christians can view it as an invitation to thoughtful stewardship — neither fatalistic about disease nor utopian about supplements — while trusting the Sovereign who numbers our days (Psalm 139:16). Consult your doctor before making changes, as individual needs vary with age, location, skin type, diet, and comorbidities.
https://acsjournals.onlinelibrary.wiley.com/doi/10.1002/cncr.34718
https://www.naturalnews.com/2026-03-26-study-vitamin-d-boosts-skin-cancer-treatment.html