Skin cancer is the most common cancer in the United States, and the vast majority are non-melanoma skin cancers (NMSC)—primarily basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (cSCC). While these cancers are usually highly treatable when caught early, they can cause significant scarring, require surgery, and occasionally become life-threatening.

The good news? There are several evidence-based ways to reduce your risk beyond simply wearing sunscreen.

As a board-certified dermatologist in San Francisco, I help patients not only detect skin cancer early but also develop personalized prevention strategies—especially for those with significant sun damage, multiple precancers, or a history of skin cancer.

Who Is at Highest Risk?

Your risk of developing non-melanoma skin cancer is higher if you:

• Have fair skin, light eyes, or blonde or red hair

• Spend significant time outdoors for work or recreation

• Have a history of blistering sunburns

• Have numerous actinic keratoses ("precancerous spots")

• Have previously been diagnosed with basal cell or squamous cell carcinoma

• Have a weakened immune system

• Are over age 50

• Have a family history of skin cancer

Many of my San Francisco patients fall into these categories because they enjoy hiking, running, cycling, tennis, golf, skiing, sailing, or other outdoor activities throughout Northern California.

1. Daily Sunscreen Is Still the Foundation

No prevention plan replaces consistent sun protection.

I recommend:

• Broad-spectrum SPF 30 or higher every day

• Reapplication every two hours outdoors

• Wide-brimmed hats and UPF clothing

• Seeking shade during peak UV hours

• Avoiding tanning beds completely

Daily sunscreen has been shown to reduce the development of actinic keratoses and squamous cell carcinoma.

2. Nicotinamide (Vitamin B3): One of the Best-Studied Supplements for Skin Cancer Prevention

Many patients ask whether any vitamins actually reduce skin cancer risk.

One of the few supplements with strong clinical evidence is nicotinamide (vitamin B3).

In a landmark randomized controlled trial, patients with a history of multiple skin cancers who took 500 mg twice daily developed:

• 23% fewer new basal and squamous cell skin cancers

• Approximately 30% fewer squamous cell carcinomas

• Significantly fewer actinic keratoses (precancers)

Additional research suggests patients may benefit most when nicotinamide is started after their first skin cancer diagnosis.

How Does Nicotinamide Work?

Unlike niacin, nicotinamide does not cause flushing.

Instead, it works by helping skin cells repair UV-induced DNA damage. It restores cellular energy (ATP) after ultraviolet exposure, allowing the skin's natural DNA repair mechanisms to function more effectively while also reducing UV-induced immune suppression.

One Important Caveat

The benefit only lasts while you continue taking it.

Studies show that once nicotinamide is stopped, the protective effect disappears. This is something I discuss with patients when deciding whether long-term supplementation makes sense.

3. Treat the "Field of Cancerization"—Not Just Individual Precancers

Most people think of skin cancer prevention as treating one precancerous spot at a time.

In reality, sun damage often affects an entire area of skin.

Dermatologists call this field cancerization, meaning large areas of chronically sun-damaged skin contain microscopic abnormal cells long before they become visible.

Common locations include:

• Face

• Scalp

• Ears

• Nose

• Chest

• Forearms

• Hands

Treating the entire field may reduce the development of future cancers.

4. Fractional Thulium Laser (Fraxel Dual 1927): More Than Cosmetic

Many people know the 1927 nm Fraxel Dual laser as a treatment for sun spots and improving skin texture.

Emerging research suggests it may also play an important role in skin cancer prevention.

Clinical studies have demonstrated:

• Up to 86% reduction in actinic keratoses

• Improvement in abnormal precancerous skin changes under the microscope

• Longer time before developing future keratinocyte cancers compared with untreated patients

Why Might Fraxel Help Prevent Skin Cancer?

Researchers believe fractional laser works through several mechanisms:

• Removing DNA-damaged skin cells

• Stimulating healthier collagen production

• Rejuvenating aging skin

• Restoring normal cellular signaling that protects against UV-induced mutations

• Improving the skin's immune response

While additional long-term studies are ongoing, this is an exciting area of preventive dermatology for patients with extensive sun damage.

5. Pulsed Dye Laser (Vbeam): An Unexpected Prevention Tool

Vbeam is traditionally used to treat:

• Rosacea

• Broken blood vessels

• Surgical scars

• Redness

Interestingly, newer research suggests patients with previous facial skin cancers who underwent 595 nm pulsed dye laser (Vbeam) treatments developed about half as many future facial keratinocyte cancers compared with similar patients who did not receive laser treatment.

Although more research is needed before recommending Vbeam solely for prevention, these findings are encouraging—particularly for patients already receiving treatment for sun damage or vascular changes.

6. Prescription Field Therapy: 5-Fluorouracil

For patients with numerous actinic keratoses, I frequently recommend prescription 5-fluorouracil (5-FU) cream.

When applied to chronically sun-damaged skin, studies have shown it can reduce future squamous cell carcinoma risk by approximately 75% during the first year after treatment.

Although treatment temporarily causes redness, crusting, and peeling, it remains one of the most effective methods for treating widespread precancerous damage.

7. Oral Polypodium Leucotomos: Helpful, But Not a Substitute

Patients often ask about oral sun protection supplements such as Polypodium leucotomos.

Research suggests this plant extract may:

• Reduce UV-induced inflammation

• Increase the amount of UV exposure needed to cause sunburn

• Reduce oxidative stress

• Enhance DNA repair

However, unlike nicotinamide, there is currently no clinical evidence that it directly prevents basal cell or squamous cell skin cancers in humans. I consider it an adjunct—not a replacement—for sunscreen and other proven prevention strategies.

8. Regular Skin Checks Save Lives—and Surgery

Even the best prevention strategy cannot eliminate skin cancer risk completely.

That's why I recommend regular full-body skin examinations, especially for patients who have:

• Previous skin cancers

• Multiple actinic keratoses

• Significant cumulative sun damage

• A family history of melanoma or non-melanoma skin cancer

Early detection often means smaller procedures, better cosmetic outcomes, and less invasive treatment.

My Approach to Skin Cancer Prevention in San Francisco

Every patient's prevention plan should be individualized.

Depending on your history, your plan may include:

• Annual or semiannual skin cancer screenings

• Daily sunscreen education

• Nicotinamide supplementation

• Cryotherapy for individual precancers

• Prescription field therapy such as 5-fluorouracil

• Fractional laser treatments for field cancerization

• Vbeam laser when clinically appropriate

• Education on performing monthly self-skin examinations

Preventing skin cancer isn't about a single treatment—it's about combining evidence-based strategies to reduce cumulative damage over time.

Schedule a Skin Cancer Prevention Consultation

If you've had basal cell carcinoma, squamous cell carcinoma, numerous precancers, or extensive sun damage, we can develop a personalized prevention plan based on your skin type, risk factors, and goals.

At Caren Campbell MD Dermatology in San Francisco, I provide comprehensive skin cancer screenings, actinic keratosis treatment, laser therapy, and individualized prevention strategies to help patients stay healthy while minimizing future procedures.

Schedule your consultation today to create a proactive plan for healthier skin for years to come.