Several prescription creams and ointments can treat precancerous skin cells, with 5-fluorouracil (5-FU) cream and imiquimod cream being the most widely used. Others include diclofenac sodium gel and, more recently, tirbanibulin ointment. Each works through a different mechanism, and the right choice depends on the number of lesions, their location, and whether you are otherwise healthy or have a condition that raises your skin cancer risk. The same creams also show up in treating precancerous changes on mucosal surfaces like the vulva, adding a dimension many people don’t expect.
Why Creams Instead of Freezing or Surgery
Most precancerous skin lesions are actinic keratoses, rough or scaly patches caused by years of sun exposure. A single spot can be frozen off with liquid nitrogen (cryotherapy), but many people don’t have just one. When sun damage is widespread, the visible patches are only part of the problem. The surrounding skin can harbor invisible DNA-damaged cells in what dermatologists call “field cancerization.” Lesion-directed treatments like cryotherapy handle individual spots but leave those subclinical changes untouched.1SKIN The Journal of Cutaneous Medicine. The Role of Field Cancerization in Selecting Therapies for Actinic Keratosis: An Expert Consensus Panel Topical creams, by contrast, are spread across an entire area of skin, treating both the visible lesions and the damaged field around them. That field-directed approach may reduce the chance of new lesions cropping up later and could lower the risk of progression to squamous cell carcinoma.2PubMed. Field Cancerization Therapies for the Management of Actinic Keratosis: An Updated Review
5-Fluorouracil Cream
5-fluorouracil, often called 5-FU, has been the go-to topical treatment for actinic keratoses for decades. It comes in several concentrations, with 5% and 4% being the most common. You apply it to the affected area once or twice daily, typically for two to four weeks depending on the formulation. The cream works by blocking an enzyme that rapidly dividing cells need to copy their DNA. Without that enzyme, precancerous cells can’t replicate and eventually die off.3Journal of Drugs in Dermatology. Synergistic Mechanisms of 5-Fluorouracil and Imiquimod in the Treatment of Actinic Keratoses Normal, healthy skin cells divide more slowly and recover after treatment, which is why the cream selectively destroys the abnormal ones.
In a randomized trial, participants who used 5-FU cream on the face or ears saw roughly a 73% reduction in actinic keratoses at six months, compared with about a 24% reduction in a control group that received only sun protection. That benefit persisted over several years of follow-up.4JAMA Dermatology. Long-term Efficacy of Topical Fluorouracil Cream, 5%, for Treating Actinic Keratosis: A Randomized Clinical Trial Clearance rates with the 4% concentration are broadly similar, though recurrence is common: in studies of patients who initially cleared completely, about half saw at least some lesions return within a year.5PubMed Central. Evaluating the Efficacy and Safety of 4% 5-Fluorouracil Cream in Patients with Actinic Keratosis: An Expert Opinion
The main downside is the skin reaction. During treatment the area becomes red, raw, and can burn or peel. Some people describe it as looking like a bad sunburn. These effects are expected signs that the cream is working, but they can be intense enough that people cut treatment short. Severe adverse reactions are rare but have been reported, including allergic contact dermatitis.6PubMed Central. Life-Threatening Reaction with Topical 5-Fluorouracil Despite the discomfort, 5-FU remains one of the least expensive topical options, which keeps it front and center in treatment guidelines.
Imiquimod Cream
Imiquimod takes a completely different approach. Rather than directly killing precancerous cells the way 5-FU does, it kicks the immune system into action. The cream binds to specific receptors on immune cells in the skin, triggering them to release signaling molecules that recruit other immune fighters to the area. It also enhances antigen-presenting cells’ ability to flag abnormal cells for destruction, essentially training the body’s own defenses to clear the lesions.7PubMed Central. Imiquimod – Its role in the treatment of cutaneous malignancies This dual action on both the innate and adaptive arms of immunity gives imiquimod antitumor and antiviral properties.8PubMed. Recent advances in treating female genital human papillomavirus related neoplasms with topical imiquimod
Imiquimod is available in 5%, 3.75%, and 2.5% formulations. The lower-concentration versions were developed partly to improve tolerability. In trials of the 3.75% cream applied daily in two cycles of two or three weeks (separated by a rest period), about a third of patients cleared completely, and the median reduction in lesion count was around 80%.9PubMed. Imiquimod 2.5% and 3.75% for the treatment of actinic keratoses: results of two placebo-controlled studies of daily application to the face and balding scalp for two 3-week cycles A second set of trials using two two-week cycles showed similar numbers, with complete clearance in about 36% and a median lesion reduction near 82% for the 3.75% cream.10PubMed. Imiquimod 2.5% and 3.75% for the treatment of actinic keratoses: results of two placebo-controlled studies of daily application to the face and balding scalp for two 2-week cycles The 2.5% cream consistently clears fewer lesions than the 3.75%, though it causes less irritation.
Like 5-FU, imiquimod makes the treated skin red, swollen, and sometimes crusty. Because the cream provokes an immune reaction, some patients develop flu-like symptoms including fatigue and body aches. The reaction is typically less prolonged than with 5-FU because the treatment cycles are shorter, but the peak intensity can be comparable.
Tirbanibulin Ointment
Tirbanibulin is the newest entrant, approved in 2020. It is a 1% ointment applied once daily for just five consecutive days, making it the shortest treatment course of any topical option. Its mechanism is distinct from both 5-FU and imiquimod. Tirbanibulin inhibits tubulin polymerization, which is the process cells need to pull their chromosomes apart during division. It also disrupts a signaling pathway involved in the progression from precancerous cells toward squamous cell carcinoma.11PubMed Central. 1% Tirbanibulin Ointment for the Treatment of Actinic Keratoses Preclinical studies suggest this drug’s effects on cell division are reversible in normal cells, which may explain why it is generally well tolerated. The ointment also triggers programmed cell death through multiple pathways and interferes with a protein called Src kinase that plays a role in cancer progression.12PubMed Central. Topical Pharmacological Treatment of Actinic Keratoses: Focus on Tirbanibulin 1% Ointment
The five-day regimen is a real advantage for people who struggle with weeks of treatment-related skin irritation. Local reactions still occur, including redness, flaking, and crusting, but they tend to resolve faster than with longer therapies. The trade-off is that tirbanibulin is more expensive, and long-term recurrence data are still accumulating since it has only been available for a few years.
Diclofenac Sodium Gel
Diclofenac 3% in hyaluronic acid 2.5% gel is the gentlest of the prescription topicals. Most people know diclofenac as an anti-inflammatory painkiller, and that anti-inflammatory action is central to how it treats actinic keratoses. It inhibits the COX enzyme pathway, which reduces a signaling molecule that helps precancerous cells survive and grow blood vessels. Research also suggests it has direct effects on pushing abnormal cells toward programmed cell death.13PubMed Central. Treatment of actinic keratosis through inhibition of cyclooxygenase‐2: Potential mechanism of action of diclofenac sodium 3% in hyaluronic acid 2.5%
The catch is treatment duration. Diclofenac gel is typically applied twice daily for 60 to 90 days, which is far longer than any of the other creams. Clearance rates tend to be lower as well. On the positive side, the skin reaction is much milder, so it suits people who cannot tolerate the intense inflammation that 5-FU or imiquimod produces. It can be a reasonable first step for mild, scattered actinic keratoses, or a bridge option for patients who have tried and abandoned a more aggressive cream.
Combining Creams for a Bigger Effect
One of the more interesting developments is combining 5-FU with calcipotriol, a synthetic form of vitamin D usually prescribed for psoriasis. In a randomized trial, patients who applied this combination to the face for four days saw an average reduction in actinic keratoses of about 88%, compared with roughly 26% for 5-FU with a placebo cream.14JCI Insight. Randomized trial of calcipotriol combined with 5-fluorouracil for skin cancer precursor immunotherapy The calcipotriol appears to switch on a signaling molecule in the skin that then synergizes with 5-FU’s cell-killing effect, driving a strong immune response involving T cells that target abnormal keratinocytes.15PubMed Central. Calcipotriol and 5-Fluorouracil Combination Therapy for the Treatment of Actinic Keratosis in the Clinic: A Review Article The short treatment window and the dramatic clearance rate have generated considerable excitement, though this combination is not yet a standardized, FDA-approved regimen and is used off-label when prescribed.
How Creams Compare to Other Field Treatments
Photodynamic therapy, or PDT, is the main non-cream field treatment. It involves applying a light-sensitizing agent to the skin and then exposing it to a specific wavelength of light. In an observational study comparing PDT, cryotherapy, and imiquimod, PDT showed the highest clearance rate at about 77%, followed by cryotherapy at roughly 71% and imiquimod at 68%, though those differences were not statistically significant. Cryotherapy had the lowest recurrence rate at about 4%, versus 7% for PDT and 11% for imiquimod.16PubMed Central. Treatment of Actinic Keratosis: The Best Choice through an Observational Study
Cost matters here. A Dutch trial-based analysis found that 5-FU had the lowest total treatment costs at roughly €433 over 12 months, compared with about €728 for imiquimod and €1,621 for photodynamic therapy.17British Journal of Dermatology. A trial‐based cost‐effectiveness analysis of topical 5‐fluorouracil vs. imiquimod vs. ingenol mebutate vs. methyl aminolaevulinate conventional photodynamic therapy for the treatment of actinic keratosis in the head and neck area performed in the Netherlands A separate cost-effectiveness model estimated that imiquimod was likely cost-effective compared with PDT at commonly used willingness-to-pay thresholds, despite a very slight difference in quality-of-life outcomes.18PubMed. Cost effectiveness of imiquimod 5% cream compared with methyl aminolevulinate-based photodynamic therapy in the treatment of non-hyperkeratotic, non-hypertrophic actinic (solar) keratoses: a decision tree model For most patients, the take-home is that creams, especially 5-FU, are considerably cheaper while offering broadly comparable long-term results. PDT is faster and involves fewer days of at-home discomfort, which justifies its cost for some people.
Organ Transplant Recipients and Other High-Risk Groups
People who take immunosuppressive medications after an organ transplant face a dramatically elevated risk of skin cancer, and their actinic keratoses are more numerous and more likely to progress. Both 5-FU and imiquimod are used in this population, but with some important differences in how well they work and how carefully they need to be monitored.
Topical 5-FU cream applied twice daily has shown high initial clearance rates in kidney transplant patients, though lesions tend to recur over the following year.19American Journal of Transplantation. Comprehensive Review Skin Cancers in Organ Transplant Recipients Imiquimod initially raised concern in this group because it activates the immune system, and theoretically that could trigger rejection of the transplanted organ. Several small trials, however, found it was relatively safe when applied to limited areas, achieving complete clearance in roughly 62 to 83% of patients without significant changes in graft function.19American Journal of Transplantation. Comprehensive Review Skin Cancers in Organ Transplant Recipients
PDT may actually outperform 5-FU cream in transplant recipients. A randomized intrapatient study that treated different areas of each patient’s skin with either PDT or 5-FU found that PDT achieved complete resolution in about 89% of treated areas, compared with just 11% for 5-FU. Cosmetic outcomes and patient preference also favored PDT.20PubMed Central. Treatment of post-transplant premalignant skin disease: a randomized intrapatient comparative study of 5-fluorouracil cream and topical photodynamic therapy That’s a striking difference, and it suggests that for transplant patients specifically, a dermatologist might lean toward PDT when it’s available, while reserving 5-FU or imiquimod for situations where clinic-based light therapy isn’t practical.
Precancerous Cells Beyond the Skin
Imiquimod and 5-FU also have roles in treating precancerous changes on mucosal surfaces, particularly those driven by human papillomavirus (HPV). Vulvar intraepithelial neoplasia, a precancerous condition of the vulvar skin, is one area where imiquimod has been studied carefully. In a randomized trial, about 81% of women treated with imiquimod had a significant reduction in lesion size at 20 weeks, and HPV cleared from the lesion in 58% of imiquimod-treated patients compared with 8% on placebo.21PubMed. Treatment of vulvar intraepithelial neoplasia with topical imiquimod A later randomized trial of vulvar high-grade precancerous lesions found that 80% of patients treated with imiquimod achieved a complete clinical response, essentially matching the 79% clearance seen with surgery.22PubMed Central. Imiquimod for Anal High Grade Intraepithelial Neoplasia: A Systematic Review
For anal high-grade precancerous lesions, also usually HPV-related, treatment options include imiquimod, 5-FU, and other topical agents alongside surgical approaches.22PubMed Central. Imiquimod for Anal High Grade Intraepithelial Neoplasia: A Systematic Review These non-skin uses highlight how the same immune-activating and cell-killing principles that work against sun-damaged keratinocytes can apply to virus-driven precancers in very different parts of the body.
Picking a Cream and What to Expect
There is no single best cream for everyone. The decision usually comes down to a handful of practical factors:
- Number of lesions: A few scattered spots might be frozen off individually. Widespread damage across the forehead, scalp, or forearms points toward a field-directed cream.
- Tolerance for skin reactions: 5-FU and imiquimod both cause substantial redness and peeling. If that’s a dealbreaker, diclofenac gel is milder, or tirbanibulin’s five-day course limits the window of discomfort.
- Treatment duration: 5-FU runs two to four weeks, imiquimod involves cycles spanning roughly six weeks total, diclofenac can take three months, and tirbanibulin takes five days.
- Cost and insurance: 5-FU is the cheapest option by a wide margin. Tirbanibulin is the most expensive, and insurance coverage varies.
- Immune status: Transplant recipients may respond differently, and imiquimod use in that group requires close monitoring of organ function.
Whichever cream you use, the treated skin goes through a predictable cycle: first redness, then irritation that can include crusting or erosion, and finally healing with fresh pink skin underneath. The reaction typically peaks about two-thirds of the way through the treatment course. Many people are alarmed by how aggressive the response looks, especially with 5-FU, but that inflammation is a sign the cream is reaching abnormal cells. Your dermatologist will usually schedule a follow-up visit a few weeks after you finish to assess clearance and decide whether a second course is needed.
Measuring What Matters to Patients
Until recently, treatment success was measured almost entirely by counting how many lesions disappeared. Dermatologists are increasingly recognizing that the patient’s experience matters just as much. A consensus effort among experts recently developed a questionnaire that captures both clinical outcomes and patient-reported factors like the severity of local skin reactions, cosmetic satisfaction, and overall treatment burden.23JAAD International. Developing a questionnaire for assessing clinician- and patient-reported outcomes in actinic keratosis: Results from an expert panel That shift is important because a cream with a slightly lower clearance rate but far less misery during treatment could end up being the better choice for someone who would otherwise abandon a more aggressive regimen halfway through. A treatment that gets completed beats a treatment that gets left in the medicine cabinet.
Recurrence is the other reality to prepare for. Actinic keratoses are not a one-and-done problem. Even after a successful round of cream therapy, new lesions often develop over the following months and years, because the underlying UV damage to your skin’s DNA doesn’t go away. Regular follow-up visits and consistent sunscreen use are just as important as the initial treatment course. Some dermatologists recommend periodic “maintenance” rounds of a topical cream, particularly for patients with a heavy burden of sun damage, though formal guidelines on maintenance schedules are still evolving.