Skin Cancer — Non-Melanoma (BCC & SCC)

Overview

Non-melanoma skin cancers (NMSC) are the most common cancers in humans — an estimated 5.4 million cases treated annually in the US alone. Basal cell carcinoma (BCC) accounts for ~80% of NMSC; squamous cell carcinoma (SCC) ~20%. Both arise from keratinocytes in the epidermis and are primarily caused by cumulative UV radiation exposure. BCC rarely metastasizes (<0.1%) but causes significant local tissue destruction. Cutaneous SCC (cSCC) metastasizes in ~3–5% of cases (higher in immunosuppressed patients — up to 20%). Merkel cell carcinoma (MCC) is a rare but aggressive neuroendocrine skin cancer (~3,000 cases/year in the US) with high metastatic potential. Five-year survival: BCC/SCC >95% (localized); cSCC with nodal metastases ~50%; MCC ~40% (distant). Risk factors: UV radiation (primary), immunosuppression (organ transplant recipients have 65–250x increased SCC risk), arsenic exposure, HPV (SCC), Gorlin syndrome (BCC — PTCH1 mutations), xeroderma pigmentosum. Treatments: surgical excision (Mohs micrographic surgery for high-risk BCC/SCC), radiation, topical therapies (5-fluorouracil, imiquimod, photodynamic therapy for superficial BCC/SCC), vismodegib and sonidegib (Hedgehog pathway inhibitors — advanced/metastatic BCC), cemiplimab (anti-PD-1 — advanced cSCC and BCC; FDA approved 2018/2021), pembrolizumab (advanced cSCC), avelumab (MCC — FDA approved 2017). 2025–2026 advances: cemiplimab adjuvant for high-risk resected cSCC (EMPOWER-CSCC-7 trial — results 2025; evaluating cemiplimab adjuvant after surgery + radiation for high-risk cSCC); nivolumab + ipilimumab for advanced BCC (Phase II: 38% ORR after Hedgehog inhibitor failure — superior to cemiplimab monotherapy 31% ORR); fianlimab (anti-LAG-3) + cemiplimab for advanced cSCC (Phase III EMPOWER-CSCC-5 vs cemiplimab alone — results expected 2025–2026); pembrolizumab + chemotherapy for MCC (Phase II activity); avelumab adjuvant for high-risk resected MCC (JAVELIN Merkel 200 adjuvant arm); retifanlimab (anti-PD-1) for advanced cSCC (PODIUM-203: 36% ORR — alternative to cemiplimab/pembrolizumab); goraxaciclib (CDK4/6 inhibitor) for advanced BCC after Hedgehog inhibitor failure; efinaconazole (topical antifungal) repurposed for superficial BCC; tirbanibulin (Klisyri — tubulin/Src inhibitor) FDA approved 2020 for actinic keratoses on face/scalp; nicotinamide riboside (NR) vs nicotinamide for NMSC prevention being evaluated; comprehensive immunosuppression management in organ transplant recipients — switching from calcineurin inhibitors to mTOR inhibitors (sirolimus, everolimus) reduces NMSC incidence by 56% (CONVERT trial). Nutritional rationale: UV-induced oxidative DNA damage is the primary mechanism — antioxidants (nicotinamide, astaxanthin, lycopene, omega-3) reduce UV-induced DNA damage and immune suppression; nicotinamide (vitamin B3 amide) is the most evidence-based supplement for NMSC prevention — RCT showing 23% reduction in new NMSC in high-risk patients; immunosuppressed transplant patients require aggressive photoprotection and nutritional support.

Core Nutrition Principles

• 1Nicotinamide (vitamin B3 amide, NOT niacin) is the most evidence-based supplement for NMSC prevention — 500mg twice daily reduced new NMSC by 23% and actinic keratoses by 11% in a Phase III RCT (Chen et al., 2015)
• 2UV radiation generates reactive oxygen species causing DNA damage (cyclobutane pyrimidine dimers) — antioxidants (astaxanthin, lycopene, vitamin C, vitamin E, selenium) reduce UV-induced oxidative DNA damage
• 3Omega-3 EPA/DHA reduce UV-induced prostaglandin E2 and immunosuppression — photoprotective; reduce UV-induced DNA damage; multiple RCTs show reduced actinic keratoses with omega-3 supplementation
• 4Green tea EGCG applied topically and consumed orally reduces UV-induced DNA damage and immune suppression — photoprotective and anti-tumor mechanisms
• 5Lycopene (tomatoes, watermelon) provides internal photoprotection — reduces UV-induced erythema and DNA damage; antioxidant; anti-tumor
• 6Vitamin D deficiency is paradoxical in NMSC — UV causes both NMSC and vitamin D synthesis; supplementation supports immune surveillance without UV exposure
• 7Immunosuppressed organ transplant recipients have dramatically increased NMSC risk — aggressive photoprotection, nicotinamide, and antioxidant nutrition are essential
• 8Alcohol increases NMSC risk by impairing DNA repair and immune surveillance — reduction or cessation recommended

• Cooked tomatoes and tomato paste — lycopene; internal photoprotection; reduces UV-induced erythema and DNA damage; cooking increases lycopene bioavailability; eat daily
• Watermelon — lycopene; high water content; hydration; photoprotective; anti-tumor
• Wild-caught fatty fish (salmon, sardines, mackerel) — omega-3 EPA/DHA; reduce UV-induced prostaglandin E2 and immunosuppression; photoprotective; anti-tumor
• Green tea (3–5 cups/day) — EGCG; reduces UV-induced DNA damage and immune suppression; anti-tumor in BCC and SCC cell lines; antioxidant
• Brazil nuts (2/day) — selenium (200mcg); antioxidant; DNA repair; associated with reduced NMSC risk
• Citrus fruits (oranges, grapefruit, lemons) — vitamin C; antioxidant; collagen synthesis for wound healing post-surgery; flavonoids; photoprotective
• Carrots, sweet potatoes, and orange vegetables — beta-carotene; antioxidant; photoprotective; immune support
• Berries (blueberries, raspberries, blackberries) — anthocyanins; antioxidants; anti-tumor; anti-inflammatory; DNA repair support
• Cruciferous vegetables (broccoli, cauliflower, Brussels sprouts) — sulforaphane; NRF2 activation; DNA repair; anti-tumor; photoprotective
• Olive oil — oleocanthal; anti-inflammatory; monounsaturated fats; photoprotective; Mediterranean diet cornerstone
• Dark chocolate (>85% cacao) — flavonoids; antioxidants; photoprotective; anti-inflammatory

• Nicotinamide (vitamin B3 amide) — 500mg twice daily; MOST EVIDENCE-BASED supplement for NMSC prevention; Phase III RCT: 23% reduction in new NMSC and 11% reduction in actinic keratoses in high-risk patients; enhances DNA repair; reduces UV-induced immunosuppression; use nicotinamide NOT niacin (no flushing)
• Astaxanthin — 12–24mg daily; most potent carotenoid antioxidant (6,000x more potent than vitamin C); photoprotective; reduces UV-induced oxidative DNA damage; anti-tumor in BCC and SCC cell lines; anti-inflammatory
• Omega-3 EPA/DHA — 3–4g daily; reduce UV-induced prostaglandin E2 and immunosuppression; photoprotective; anti-tumor; multiple RCTs show reduced actinic keratoses
• Vitamin D3 — 5,000–10,000 IU daily with K2 (200mcg MK-7); immune surveillance; anti-tumor; supplementation avoids UV exposure needed for cutaneous synthesis; target 60–80 ng/mL
• Lycopene — 15–30mg daily; internal photoprotection; reduces UV-induced erythema and DNA damage; anti-tumor; take with fat for absorption
• Selenium (selenomethionine) — 200mcg daily; antioxidant; DNA repair; associated with reduced NMSC risk; immune support; do not exceed 400mcg/day
• Vitamin C (liposomal) — 2,000–4,000mg daily; antioxidant; collagen synthesis for wound healing post-surgery; photoprotective; immune support
• Vitamin E (mixed tocopherols) — 400 IU daily; antioxidant; photoprotective; reduces UV-induced DNA damage; take with vitamin C for synergistic effect
• Green tea extract (EGCG) — 400–800mg daily standardized to 45% EGCG; reduces UV-induced DNA damage; anti-tumor; antioxidant; photoprotective
• Curcumin (phytosome) — 500–1,000mg twice daily; anti-tumor in BCC and SCC cell lines; NF-kB inhibition; anti-inflammatory; photoprotective
• Polypodium leucotomos extract — 240–480mg daily; fern extract with strong photoprotective properties; reduces UV-induced DNA damage and erythema in RCTs; anti-inflammatory
• Zinc picolinate — 30mg daily; DNA repair; wound healing post-surgery; immune function; antioxidant

• Mohs micrographic surgery — gold standard for high-risk BCC and SCC; complete margin assessment; highest cure rates (99% for primary BCC); tissue-sparing; preferred for face, ears, nose, lips, eyelids
• Standard surgical excision — for low-risk BCC and SCC; 4–6mm margins for BCC; 4–10mm margins for SCC based on risk features
• Topical 5-fluorouracil (Efudex) — for superficial BCC and actinic keratoses; 5% cream applied twice daily for 3–6 weeks; inflammatory reaction indicates efficacy
• Imiquimod (Aldara) — immune response modifier; for superficial BCC and actinic keratoses; 5% cream applied 5 days/week for 6 weeks
• Photodynamic therapy (PDT) — for superficial BCC, SCC in situ (Bowen disease), and actinic keratoses; aminolevulinic acid (ALA) or methyl-ALA + red light activation; excellent cosmetic outcomes
• Vismodegib (Erivedge) — Hedgehog pathway inhibitor (SMO inhibitor); FDA approved for advanced/metastatic BCC; 47% ORR; 9.5-month median response duration; significant side effects (muscle cramps, alopecia, dysgeusia)
• Sonidegib (Odomzo) — Hedgehog pathway inhibitor; FDA approved for locally advanced BCC; 56% ORR; similar side effect profile to vismodegib
• Cemiplimab (Libtayo) — anti-PD-1; FDA approved 2018 for advanced cSCC; 47% ORR; FDA approved 2021 for advanced BCC after Hedgehog inhibitor failure; 31% ORR
• Pembrolizumab — anti-PD-1; FDA approved for advanced cSCC; 34% ORR; KEYNOTE-629
• Avelumab (Bavencio) — anti-PD-L1; FDA approved 2017 for Merkel cell carcinoma; 33% ORR; first immunotherapy approved for MCC
• Pembrolizumab for MCC — FDA approved 2018; 56% ORR in treatment-naive MCC; KEYNOTE-017
• Radiation therapy — for inoperable BCC/SCC; adjuvant for high-risk resected SCC with perineural invasion or positive margins; definitive for MCC
• UV protection — SPF 50+ broad-spectrum sunscreen daily (reapply every 2 hours); UPF 50+ clothing; wide-brim hat; UV-blocking sunglasses; avoid tanning beds; seek shade 10am–4pm; most important prevention strategy
• Actinic keratosis treatment — treat all AKs (SCC precursors); liquid nitrogen cryotherapy, topical 5-FU, imiquimod, PDT, or diclofenac gel; field treatment for multiple AKs
• Nivolumab + ipilimumab for advanced BCC — Phase II: 38% ORR after Hedgehog inhibitor failure; superior to cemiplimab monotherapy (31% ORR); emerging standard for BCC after vismodegib/sonidegib failure
• Cemiplimab adjuvant for high-risk resected cSCC (EMPOWER-CSCC-7) — evaluating cemiplimab adjuvant after surgery + radiation for high-risk cSCC; results expected 2025; could establish adjuvant immunotherapy as standard for high-risk resected cSCC
• Retifanlimab (Zynyz) — anti-PD-1; PODIUM-203: 36% ORR in advanced cSCC; FDA approved 2023 for MCC; alternative to cemiplimab/pembrolizumab for advanced cSCC
• Tirbanibulin (Klisyri) — tubulin/Src inhibitor; FDA approved 2020 for actinic keratoses on face/scalp; 1% ointment applied once daily for 5 days; alternative to 5-FU and imiquimod for AKs
• mTOR inhibitor switch for organ transplant recipients — switching from calcineurin inhibitors (cyclosporine, tacrolimus) to sirolimus or everolimus reduces NMSC incidence by 56% (CONVERT trial); discuss with transplant team for patients with multiple NMSCs
• Fianlimab + cemiplimab (EMPOWER-CSCC-5) — anti-LAG-3 + anti-PD-1; Phase III vs cemiplimab alone for advanced cSCC; results expected 2025–2026; same platform showing superiority in melanoma
• Dermatology surveillance — full-body skin exam every 3–6 months for high-risk patients; monthly self-examination; total body photography