If you have actinic keratoses —those rough, scaly patches caused by years of sun damage—or have a history of multiple non-melanoma skin cancers, you understand the frustration of the “treatment cycle.” Even with advanced interventions like laser-assisted photodynamic therapy , some patients continue to develop difficult-to-control precancerous changes.
Researchers are exploring the use of Gardasil 9, a vaccine originally designed to prevent human papillomavirus (HPV) infections, as a tool to help reduce the risk of actinic keratoses and related skin cancers. However, this is not a “magic bullet” for everyone, and the evidence requires careful interpretation.
[Book a 20-minute Clinical Consultation with Dr. Chris]
- What is Gardasil 9?
- Understanding Actinic Keratoses and NMSC
- The Link Between HPV and Skin Cancer
- Clinical Evidence: The VAXAK Trial Results
- What “Off Label” Means for You
- Benefits, Risks, and Limitations
What is Gardasil 9?
Gardasil 9 is a vaccine designed to protect against certain strains of the Human Papillomavirus (HPV). HPV is a common virus transmitted through skin-to-skin contact. While it is most famous for its link to cervical, anal, and throat cancers, it is a broad family of viruses with many different strains.
The vaccine works by prompting your immune system to recognise and fight these specific HPV strains. It has a long-standing, strong safety record and is routinely administered to adolescents worldwide.
Actinic Keratoses (AK) and Non-Melanoma Skin Cancer (NMSC)
Actinic Keratoses , often called “solar keratoses,” are precancerous lesions. While they are not skin cancer yet, a percentage of them can progress into Squamous Cell Carcinoma over time. Having dozens of these lesions across sun-exposed skin signals a high risk for future skin cancer.
Non-melanoma skin cancers (NMSC) primarily include Basal Cell Carcinoma and Squamous Cell Carcinoma . These are typically linked to cumulative UV damage. Patients with a chronic tendency to form these spots often require repeated, ongoing treatments to manage their “field” of sun damage.
Why Would an HPV Vaccine Help with Sun Damage?
It may seem unusual that a vaccine for a virus could affect sun-induced lesions. This connection exists because certain “cutaneous” (skin) strains of HPV are often present in actinic keratoses and squamous cell carcinomas.
The theory is that these skin-based HPV strains may contribute, alongside UV radiation, to the development of skin lesions. By vaccinating against HPV, the immune system may be better “educated” to recognise and attack abnormal or HPV-related cells in the skin. Additionally, the vaccine may provide a general boost to the skin’s immune surveillance, helping the body “clean up” sun-damaged cells before they turn into cancer.
The Evidence: The VAXAK Trial and the Placebo Effect
The most rigorous study to date is the VAXAK Randomised Clinical Trial, published in JAMA Dermatology in 2025. While the results showed a benefit, they also highlighted a very high response rate in the placebo group, which is important for patients to understand before deciding on treatment.
The Results:
- Reduction in Lesions: The group receiving Gardasil 9 showed a median 58% reduction in the number of actinic keratosis lesions after 12 months.
- The Placebo Comparison: Surprisingly, the placebo group (those who received a saline injection) also showed a median 47% reduction in lesions. While the vaccine performed better, the difference was relatively modest.
- No Reduction in Cancer Risk: Critically, the study did not show any reduction in actual Squamous Cell Carcinoma or Basal Cell Carcinoma risk during the study period.
- Study Limitation: A major limitation of this trial was the one-year follow-up period. One year is a very short timeframe for skin cancer development. It remains possible that longer-term observation will eventually prove a reduction in actual cancer risk, but that is currently unproven.
Who is this for?
Using Gardasil 9 off label is not a recommendation for the majority of patients. For most people with standard sun damage, traditional field therapies and sun protection remain the gold standard.
However, in a specific subset of patients—those with difficult to control actinic keratoses or a high frequency of Squamous Cell Carcinomas—the potential benefits of this immune boost may outweigh the risks. This is a clinical decision that requires a detailed discussion about your specific history.
Understanding “Off Label” Use
Using Gardasil 9 for actinic keratoses and skin cancer prevention is considered “off label.”
The Therapeutic Goods Administration (TGA) in Australia has approved Gardasil 9 for specific anogenital cancers, but it is not officially approved for skin cancer. “Off label” prescribing is a common medical practice where a doctor uses a treatment based on emerging research, such as the VAXAK trial. This requires an informed consent process where we weigh the evidence together.
Risks and Limitations
- Side Effects: Generally mild and short-lived, including soreness at the injection site, mild fever, or headache.
- Uncertain Efficacy: As seen in the trial, many patients improve regardless of the vaccine (placebo effect), and the vaccine did not completely stop new lesions from forming.
- Cost and Access: Because this use is off label, it is not covered by the PBS or insurance. The full three-dose series is an out-of-pocket expense.
- Not a Replacement: This is a supplementary tool. You must still practice strict sun protection and attend regular skin checks.
Frequently Asked Questions
Why did the placebo group improve so much? In clinical trials, all patients receive high-quality care, including regular checks and standard treatments for thick lesions. This often leads to an improvement in both groups. The vaccine is intended to provide an additional percentage of improvement over standard care.
Is it worth it if it doesn’t stop actual skin cancer? In the short term, the goal is to reduce the “lesion burden”—meaning fewer spots to freeze, burn, or treat with creams. We hope it reduces cancer risk long-term, but we are still waiting for multi-year data to confirm this.
How do I decide if this is right for me? This requires a dedicated discussion. We offer a specific 20-minute consultation to review your pathology history, your previous responses to field therapy, and the pros and cons of the vaccine protocol.