5-Fluorouracil for Actinic Keratosis Treatment and Chemoprevention: A Randomized Controlled Trial

European consensus-based interdisciplinary guideline for diagnosis, treatment and prevention of actinic keratoses, epithelial UV-induced dysplasia and field cancerization on behalf of European Association of Dermato-Oncology, European Dermatology Forum, European Academy of Dermatology and Venereology and Union of Medical Specialists (Union Européenne des Médecins Spécialistes)

A collaboration of multidisciplinary experts from the European Association of Dermato-Oncology, the European Dermatology Forum, the European Academy of Dermatology and Venereology, and the European Union of Medical Specialists was formed to develop European recommendations on AK diagnosis and treatment, based on current literature and expert consensus. This guideline addresses the epidemiology, diagnostics, risk stratification and treatments in immunocompetent as well as immunosuppressed patients. Actinic keratoses (AK) are potential precursors of cutaneous squamous cell carcinoma (cSCC) and display typical histopathologic and immunohistochemical features of this malignancy in an early stage. They can develop into cSSC in situ and become invasive in a low percentage of cases. AK is the most frequent neoplasia in white populations, frequently occurring within a cancerous field induced by ultraviolet radiation. Since it cannot be predicted, which lesion will progress to cSCC and when treatment is usually recommended. The diagnosis of AK and field cancerization is made by clinical examination. Dermatoscopy, confocal microscopy, optical coherence tomography or line-field confocal-OCT can help in the differential diagnosis of AK and other skin neoplasms. A biopsy is indicated in clinically and/or dermatoscopically suspicious and/or treatment-refractory lesions. The choice of treatment depends on patients' and lesion characteristics. For single non-hyperkeratotic lesions, the treatment can be started upon patient's request with destructive treatments or topical treatments. For multiple lesions, field cancerization treatment is advised with topical treatments and photodynamic therapy. Preventive measures such as sun protection, self-examination and repeated field cancerization treatments of previously affected skin areas in high-risk patients are advised.

Squamous cell carcinoma of the eyelid

Eyelid squamous cell carcinoma is a major type of rare eyelid cancer, together with basal cell carcinoma and sebaceous gland carcinoma. It is a painless disease that progresses slowly and is often detected by the appearance of nodules or plaques. Risk factors include exposure to ultraviolet light, fair skin, radiation and human papillomavirus infection. The standard treatment is surgical removal, and in cases of orbital invasion, orbital content removal is required. If sentinel node biopsy reveals a high risk of lymph node metastasis, adjuvant radiotherapy may be considered. Local chemotherapy, such as imiquimod and 5-fluorouracil, may be used for eyelid squamous cell carcinoma in situ. When surgery or radiotherapy is not recommended for distant metastases or locally advanced disease, drug therapy is often according to head and neck squamous cell carcinoma in Japan. The treatment often requires a multidisciplinary team to ensure the preservation of function and cosmetic appearance.

Topical treatment of actinic keratoses in organ transplant recipients: a feasibility study for SPOT (Squamous cell carcinoma Prevention in Organ transplant recipients using Topical treatments)

BACKGROUND

The risk of cutaneous squamous cell carcinoma (cSCC) is significantly increased in organ transplant recipients (OTRs). Clearance of actinic keratoses (AKs) is generally regarded as a surrogate biomarker for cSCC prevention. OTR-cSCC chemoprevention with topical AK treatments has not been investigated in randomized controlled trials (RCTs), although there is evidence that 5% 5-fluorouracil (5-FU) may be chemoprotective in immunocompetent patients.

OBJECTIVES

To assess the feasibility, activity and evaluation outcomes relevant to the design of a future phase III RCT of topical cSCC chemoprevention in OTRs.

METHODS

OTRs with 10 or more AKs in predefined areas were randomized 1 : 1 : 1 to topical 5-FU, 5% imiquimod (IMIQ) or sunscreen (sun-protective factor 30+) in a phase II, open-label RCT over 15 months. Feasibility outcomes included proportions of eligible OTRs randomized, completing treatment and willing to be re-treated. AK activity [AK clearance, new AK development, patient-centred outcomes (toxicity, health-related quality of life, HRQoL)] and evaluation methodology (clinical vs. photographic) were assessed.

RESULTS

Forty OTRs with 903 AKs were randomized. All feasibility outcomes were met (56% of eligible OTRs were randomized; 89% completed treatment; 81% were willing to be re-treated). AK activity analyses found 5-FU and IMIQ were superior to sunscreen for AK clearance and prevention of new AKs. 5-FU was more effective than IMIQ in AK clearance and prevention in exploratory analyses. Although toxicity was greater with 5-FU, HRQoL outcomes were similar.

CONCLUSIONS

Trials of topical AK treatments in OTRs for cSCC chemoprevention are feasible and AK activity results support further investigation of 5-FU-based treatments in future phase III trials. What is already known about this topic? Cutaneous squamous cell carcinoma (cSCC) is significantly more common in immunocompromised individuals including organ transplant recipients (OTRs) compared with immunocompetent populations. cSCC chemoprevention activity of sunscreen and 5-fluorouracil-based (5-FU) actinic keratosis (AK) treatments has been demonstrated in randomized controlled trials (RCTs) in immunocompetent populations but not in OTRs. AKs are cSCC precursors and their clearance and prevention are generally regarded as surrogate endpoint biomarkers for potential cSCC chemoprevention activity. What does this study add? SPOT (SCC Prevention in OTRs using Topical treatments) has confirmed that RCTs of OTR-cSCC chemoprevention with topical AK treatments are feasible. It also suggests that topical 5-FU may be superior to 5% imiquimod and sunscreen in AK clearance and prevention. Together with recent evidence from several RCTs in the general population, these data provide a compelling rationale for further studies of intervention with 5-FU-based topical chemoprevention approaches in OTR-cSCC prevention.

How to Assess the Efficacy of Interventions for Actinic Keratosis? A Review with a Focus on Long-Term Results

Actinic keratoses (AK) are common lesions of the skin caused by cumulative sun exposure. Since AK may progress to invasive cutaneous squamous cell carcinoma (cSCC), guidelines uniformly recommend early and consequent treatment. A variety of interventions are available; however, most randomized controlled trials, meta-analyses, and guidelines focus on outcomes that are usually evaluated 8–12 weeks after the end of treatment. Importantly, these assessments can capture the short-term, transient outcomes, but do not allow any conclusions about long-term results to be drawn and do not reflect the probability of transition towards cSCC. Until now, few studies have assessed the long-term results of interventions for AK. Indeed, finding the most appropriate end-point and adjunct time point for determining the long-term results of interventions for AK remains a challenge. Here, we provide an overview of the different ways of measuring the efficacy of AK treatments, such as using recurrence rates or sustained clearance rates, and discuss methodological aspects. Furthermore, we highlight the importance of evidence from post-marketing surveillance trials for the detection of efficacy values and safety signals. Additionally, we emphasize that a follow-up period of 12 months might not be sufficient to reflect the long-term results and stress the urgent need for a longer follow-up period and regular risk-stratified surveillance.

Japanese Dermatological Association Guidelines: Outlines of Guidelines for Cutaneous Squamous Cell Carcinoma 2020

In consideration of the development of treatment options for squamous cell carcinoma (SCC), the Japanese Skin Cancer Society issued the first guidelines of SCC in 2007 and revised them in 2015. Here, we report the English version of the 2020 edition of the Japanese SCC guidelines. The first half of this article is an overview of SCC including actinic keratosis and Bowen's disease, and the second half discusses three clinical questions: (i) treatment of actinic keratosis; (ii) determination of the resection margin of the primary lesion; and (iii) treatment of radically incurable cases, as contemporary problems encountered in treating SCC. In these evaluations, all processes were implemented according to the Grading of Recommendations, Assessment, Development, Evaluation system. Also, items of recommendation concerning each clinical question were determined by a multidisciplinary expert panel consisting of dermatologists, plastic/reconstructive surgeons, radiologists, and oncologists through a comprehensive literature search and systematic reviews.

A review of actinic keratosis, skin field cancerisation and the efficacy of topical therapies

While a wide range of treatments exist for actinic keratosis and skin field cancerisation, the long‐term benefits of the most common topical therapies are poorly defined. This report reviews the efficacy of the most commonly used topical therapies to treat regional or field lesions. Limited clinical and histopathological data are available on clearance rates at 12 months post‐treatment for the most commonly used agents, with varied outcome measures making any comparison difficult. In general, total field clearance rates at 12 months are suboptimal for the most commonly employed agents. Given the increasing incidence of actinic keratosis and skin field cancerisation due to an ageing population, further research into the efficacy of therapies is critical to guide treatment choice.

Use and Cost of Actinic Keratosis Destruction in the Medicare Part B Fee-for-Service Population, 2007 to 2015

Importance

Actinic keratosis is prevalent and has the potential to progress to keratinocyte carcinoma. Changes in the use and costs of actinic keratosis treatment are not well understood in the aging population.

Objective

To evaluate trends in the use and costs of actinic keratosis destruction in Medicare patients.

Design, Setting, and Participants

A billing claims analysis was performed of the Medicare Part B Physician/Supplier Procedure Summary Master Files and National Summary Data of premalignant skin lesion destructions performed from 2007 to 2015 among Medicare Part B fee-for-service beneficiaries.

Main Outcomes and Measures

Mean number of actinic keratosis lesions destroyed and associated treatment payments in 2015 US dollars estimated per 1000 Medicare Part B fee-for-service beneficiaries. Data analysis was performed from November 2017 to July 2018.

Results

More than 35.6 million actinic keratosis lesions were treated in 2015, increasing from 29.7 million in 2007. Treated actinic keratosis lesions per 1000 beneficiaries increased from 917 in 2007 to 1051 in 2015, while mean inflation-adjusted payments per 1000 patients decreased from $11 749 to $10 942 owing to reimbursement cuts. The proportion of actinic keratosis lesions treated by independently billing nurse practitioners and physician assistants increased from 4.0% in 2007 to 13.5% in 2015.

Conclusions and Relevance

This study's findings suggest that actinic keratosis imposes continuously increasing levels of treatment burden in the Medicare fee-for-service population. Reimbursement decreases have been used to control rising costs of actinic keratosis treatment. Critical research may be warranted to optimize access to actinic keratosis treatment and value for prevention of keratinocyte carcinoma.

Chemoprevention of Basal and Squamous Cell Carcinoma With a Single Course of Fluorouracil, 5%, Cream: A Randomized Clinical Trial

Importance

Keratinocyte carcinoma (ie, cutaneous basal and squamous cell carcinoma) is the most common cancer in the United States.

Objective

To determine whether topical fluorouracil could prevent surgically treated keratinocyte carcinoma.

Design, Setting, and Participants

The Veterans Affairs Keratinocyte Carcinoma Chemoprevention Trial was a randomized, double-blind, placebo-controlled trial of topical fluorouracil for chemoprevention of keratinocyte carcinoma. Participants were recruited from May 2009 to September 2011 from 12 Veterans Affairs medical centers and followed until June 30, 2013. Participants were veterans (n = 932) with a history of at least 2 keratinocyte carcinomas in the past 5 years; almost all were white males and the median age was 70 years.

Interventions

Application of fluorouracil, 5%, (n = 468) or vehicle control cream (n = 464) to the face and ears twice daily for 2 to 4 weeks upon randomization.

Main Outcomes and Measures

Surgically treated keratinocyte, basal cell, and squamous cell carcinoma risk on the face and ears in the first year after enrollment; and time to first surgically treated keratinocyte, basal cell, and squamous cell carcinoma. The a priori hypothesis was that fluorouracil would be effective in preventing these cancers.

Results

Of 932 participants (916 men [98%]; 926 white [99%]; median age, 70 years), 299 developed a basal cell carcinoma end point (95 in year 1) and 108 developed a squamous cell carcinoma end point (25 in year 1) over 4 years (median follow-up, 2.8 years). Over the entire study, there was no difference between treatment groups in time to first keratinocyte, basal cell, or squamous cell carcinoma. During the first year, however, 5 participants (1%) in the fluorouracil group developed a squamous cell carcinoma vs 20 (4%) in the control group, a 75% (95% CI, 35%-91%) risk reduction (P = .002). The 11% reduction in basal cell carcinoma risk during year 1 (45 [10%] in the fluorouracil group vs 50 [11%] in the control group) was not statistically significant (95% CI, 39% reduction to 31% increase), nor was there a significant effect on keratinocyte carcinoma risk. However, a reduction in keratinocyte carcinomas treated with Mohs surgery was observed.

Conclusions and Relevance

A conventional course of fluorouracil to the face and ears substantially reduces surgery for squamous cell carcinoma for 1 year without significantly affecting the corresponding risk for basal cell carcinoma.

Trial Registration

clinicaltrials.gov Identifier: NCT00847912.

Relative efficacy of 5-fluorouracil compared with other treatments among patients with actinic keratosis: A network meta-analysis

OBJECTIVE

The purpose of this study was to compare the efficacy of 5-fluorouracil (5-FU) with that of other treatments of actinic keratosis (AK).

METHODS

A systematic literature review of five databases (including Medline and EMBASE) was first performed to identify randomized controlled trials (RCTs). A network meta-analysis (NMA) based on a random-effects Bayesian model was then performed on the outcomes for patients with total clearance and lesions reduced from baseline. Five treatments (viz., 0.5% 5-FU with 10% salicylic acid [5-FU/SA], 5% 5-FU cream, 3% diclofenac sodium, cryosurgery, and vehicle) were evaluated.

RESULTS

A total of 11 studies involving 2,256 patients with AK were included in this NMA. The overall risk of bias among the included studies was low. All treatments were significantly better than the vehicle both for patients with total clearance and for lesions reduced from baseline. Among patients with total clearance, 5% 5-FU cream (56.8%) and 5-FU/SA (35.7%) were likely to be more effective than the other treatments, whereas 5% 5-FU cream (98.6%) was likely the most effective in the group of lesions reduced from baseline.

CONCLUSION

5-FU, diclofenac sodium, and cryosurgery are all useful for AK treatment, with 5-FU being the most effective.