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

International time trends and differences in topical actinic keratosis therapy utilization

Background

Actinic Keratoses (AK) are precancerous lesions that can lead to Squamous Cell Carcinoma. International differences in the utilization of topical medications to treat AK are not well described.

Objectives

To describe international differences in topical AK medication utilization, including associations of countries' economic status with AK medication utilization.

Methods

We used IQVIA MIDAS pharmaceutical sales data for 65 countries (42 high-income, 24 middle-income) from April 2011 to December 2021. We calculated each country's quarterly utilization of medications in grams per 1000 population. We used univariable linear regression to assess the association between country economic status and AK medication utilization.

Results

High-income countries used 15.37 more grams per 1000 population of 5-fluorouracil (95% CI: 9.68, 21.05), 4.64 more grams per 1000 population of imiquimod (95% CI: 3.45, 5.83), and 0.32 more grams per 1000 population of ingenol mebutate (95% CI: 0.05, 0.60).

Limitations

Missing medication utilization data for some countries.

Conclusion

High-income countries use more topical AK therapies than middle-income countries.

Topical Calcipotriol Plus 5-Fluorouracil in the Treatment of Actinic Keratosis, Bowen's Disease, and Squamous Cell Carcinoma: A Systematic Review

BACKGROUND/OBJECTIVES

Actinic keratoses (AK) are premalignant skin lesions caused by chronic sun exposure, topically managed by 5-fluorouracil (5-FU), diclofenac 3% gel, and imiquimod. Despite their effectiveness, long treatment duration and severe adverse local skin reactions have limited patient concordance. Calcipotriol has recently been used as a combination agent for existing topical AK treatments. A systematic review was performed to determine the clinical efficacy of 5-FU and calcipotriol for the treatment of AK, Bowen's disease, and squamous cell carcinoma (SCC).

METHODS

A systematic literature search was conducted on Medline, Embase, and Cochrane Library. Among the 84 records screened, 12 were retrieved for full-text review and 8 were included in the final analysis.

RESULTS

Among the 8 studies, there were 214 control patients and 288 patients who received the intervention. The combination 5% 5-FU with calcipotriol resulted in a significant reduction in the number of AKs on the face, scalp, right upper extremity, and left upper extremity for all sites at 8 weeks (P < .0001). No significant difference in SCC incidence was observed at 1 or 2 years, but there was a significant reduction observed at 3 years for SCC on face and scalp. No study assessed the combination for Bowen's disease.

CONCLUSIONS

Combination 5% 5-FU with calcipotriol is an effective treatment for Aks; however, future trials may consider longer treatment and follow-up periods for the treatment and prevention of AK, SCC in situ, and SCC.

Diagnosis and therapy of actinic keratosis

Actinic keratosis (AK) is considered a chronic and recurring in situ skin neoplasia, with a possible transformation into invasive squamous cell carcinoma (SCC). Among others, predominant risk factors for development of AK are UV-light exposure and immunosuppression. Basal epidermal keratinocyte atypia (AK I) and proliferation (PRO score) seem to drive malignant transformation, rather than clinical appearance of AK (Olsen I-III). Due to the invasiveness of punch biopsy, those histological criteria are not regularly assessed. Non-invasive imaging techniques, such as optical coherence tomography (OCT), reflectance confocal microscopy (RCM) and line-field confocal OCT (LC-OCT) are helpful to distinguish complex cases of AK, Bowen's disease, and SCC. Moreover, LC-OCT can visualize the epidermis and the papillary dermis at cellular resolution, allowing real-time PRO score assessment. The decision-making for implementation of therapy is still based on clinical risk factors, ranging from lesion- to field-targeted and ablative to non-ablative regimens, but in approximately 85% of the cases a recurrence of AK can be observed after a 1-year follow-up. The possible beneficial use of imaging techniques for a non-invasive follow-up of AK to detect recurrence or invasive progression early on should be subject to critical evaluation in further studies.

Diagnose und Therapie aktinischer Keratosen

Actinic keratosis (AK) is considered a chronic and recurring in situ skin neoplasia, with a possible transformation into invasive squamous cell carcinoma (SCC). Among others, predominant risk factors for development of AK are UV-light exposure and immunosuppression. Basal epidermal keratinocyte atypia (AK I) and proliferation (PRO Score) seem to drive malignant turnover, rather than clinical appearance of AK (Olsen I-III). Due to the invasiveness of punch biopsy, those histological criteria are not regularly assessed. Non-invasive imaging techniques, such as optical coherence tomography (OCT), reflectance confocal microscopy (RCM) and line-field confocal OCT (LC-OCT) are helpful to distinguish complex cases of AK, Bowen's disease and SCC. Moreover, LC-OCT can visualize the epidermis and the papillary dermis at cellular resolution, allowing real-time PRO Score assessment. The decision-making for implementation of therapy is still based on clinical risk factors, ranging from lesion- to field-targeted and ablative to non-ablative regimes, but in approximately 85% of the cases a recurrence of AK can be observed after a 1-year follow-up. The possible beneficial use of imaging techniques for a non-invasive follow-up of AK to detect recurrence or invasive progression early on should be subject to critical evaluation in further studies.

Tirbanibulin 1% Ointment for Actinic Keratosis: Results from a Real-Life Study

Background and Objectives: Tirbanibulin 1% ointment is a novel synthetic anti-proliferative agent that inhibits tubulin polymerization. It is approved for treating actinic keratosis (AK) on the face and scalp in adults. It has demonstrated good efficacy, an adequate safety profile and excellent patient adherence in the phase 3 clinical trials, however data about its real-life efficacy and safety are lacking. Here we report the experience of the dermatology unit of the University Hospital of Messina. Materials and Methods: We performed a spontaneous open-label, prospective non-randomized study to assess the effectiveness and safety of tirbanibulin 1% ointment for the treatment of 228 AKs in 38 consecutive patients-28 males (73%) and 10 females (26%)-aged between 52 and 92 years (mean age: 72 ± 8.92 years). Results: Total clearance was recorded in 51% of lesions, while partial clearance was recorded in 73% of lesions. An excellent tolerability profile and high compliance rate were observed, with no treatment discontinuation due to the onset of adverse events. Conclusion: Our real-life experience confirms the effectiveness and safety of tirbanibulin ointment for the treatment of AKs.

Evaluating the Efficacy and Safety of 4% 5-Fluorouracil Cream in Patients with Actinic Keratosis: An Expert Opinion

Actinic keratosis is a lesion that develops in sun-exposed areas of the skin and is considered to be a precancerous condition or an early in situ squamous cell carcinoma. Treatment of actinic keratosis is important for reducing skin cancer risk, with treatment choice based on patient-, lesion- and treatment-related considerations. Of the topical treatments used for field-directed therapy, those containing 5-fluorouracil are among the most effective and widely prescribed. The most recently developed topical 5-fluorouracil preparation (Tolak®; Pierre Fabre, France) contains 4% 5-fluorouracil in an aqueous cream. This narrative review discusses data on 4% 5-fluorouracil cream to treat actinic keratosis, and provides the authors' expert opinion on issues associated with it use. The effect of the cream has been evaluated in phase 2 and 3 trials of adult patients with actinic keratosis on the face, ears or scalp. These trials included patients with severe baseline disease, defined by high lesion counts and large-size treatment fields, which possibly affected the proportion of patients who were able to achieve complete clearance. Other efficacy parameters (e.g. percentage change in lesion count, ≥ 75% clearance of lesions or clinically significant changes in validated severity scales) should also be assessed to fully evaluate 4% 5-fluorouracil treatment efficacy in these patients. Nevertheless, 4% 5-fluorouracil is associated with high efficacy, a low level of recurrence and a satisfactory safety profile.

Severity of Local Skin Reactions with 4% 5-Fluorouracil Plus Emollient versus 4% 5-Fluorouracil Alone in Patients with Actinic Keratosis: A Single-Blind Randomised Trial

INTRODUCTION

Topical 5-fluorouracil (5-FU)-containing treatments are effective for actinic keratosis (AK); however, they frequently lead to transient local skin reactions (LSRs), which often result in treatment non-adherence.

METHODS

The aim of this international, phase IV clinical trial was to investigate whether addition of an emollient to topical 4% 5-FU would reduce the frequency and severity of LSRs over 4 weeks of treatment (intervention group) compared with 4% 5-FU alone (control group) in patients with AK. The primary objective was to assess the severity of LSRs (i.e. erythema, flaking/scaling, crusting, swelling, vesiculation/pustulation and erosion/ulceration) at week 4 of treatment (or before, in case of a major local reaction). Key secondary objectives were LSR total scores at weeks 2 and 8, the scores of individual LSR items at each visit, and the proportions of patients with 100% and ≥ 75% AK lesion clearance at week 8.

RESULTS

In total, 141 patients were included in the efficacy analysis (71 in the intervention group and 70 in the control group). There were no statistically or clinically significant differences between the treatment groups in terms of LSR total score at week 4 (overall and by subgroups defined by the number of lesions and patient age at baseline), scores of individual LSR items at any time point, and AK lesion clearance rates at week 8. LSR scores with topical 4% 5-FU alone were lower than expected. Skin reactions were the most common treatment-emergent adverse events in both groups, leading to treatment discontinuation in nine patients (12.3%) in the intervention group and seven (9.9%) in the control group. No new safety signals were observed with the addition of an emollient to 4% 5-FU.

CONCLUSIONS

Daily emollient applications during the 4-week treatment course did not impact the safety and efficacy profile of 4% 5-FU.

Field Therapy for Actinic Keratosis: A Structured Review of the Literature on Efficacy, Cost, and Adherence

BACKGROUND

Although there are evidence-based guidelines for actinic keratosis management, selecting a cost-effective field therapy is challenging because of limited studies comparing cost, efficacy, and adherence among treatments.

OBJECTIVE

To review the literature on field-directed therapies for actinic keratosis, comparing efficacy, cost, and adherence data for topical and in-office treatments.

MATERIALS AND METHODS

PubMed, Embase, Web of Science, and Google Scholar databases were searched from October 2020 to March 2021 for articles on field therapy for actinic keratosis. Total cost per regimen was estimated using wholesale acquisition cost package prices and Medicare coverage rates for May 2021. Effective cost was approximated by dividing total cost by complete response rate.

RESULTS

Efficacy data for various field therapies range widely, and long-term follow-up is limited. Cross-study comparisons are challenging because of heterogeneity of studies. Field-directed therapy with topical 5-fluorouracil and photodynamic therapy have similar effective cost. Adherence may significantly affect real-world efficacy and long-term clearance; this would favor shorter duration topical regimens or in-office procedures.

CONCLUSION

Standardization of future studies examining efficacy of field treatments for actinic keratosis will allow comparison across treatments. In-office treatments such as photodynamic therapy represent a cost-effective alternative to topical therapies with comparable efficacy.

Advances in Topical Treatments of Cutaneous Malignancies

Surgical excision has been the preferred treatment for cutaneous malignancies, but can be affected by various considerations. Noninvasive, self-administered topical treatments represent an alternative option. The aim of this review was to evaluate and summarize evidence-based recommendations for topical treatments of basal cell carcinoma (BCC), cutaneous squamous cell carcinoma (CSCC), in situ melanoma (MIS), and extramammary Paget's disease (EMPD). Studies were reviewed on PubMed. Included studies were summarized, assessed for biases, and assigned a level of evidence to develop treatment recommendations. For the treatment of superficial BCC, complete clearance rates ranged from 90 to 93% for 5% 5-fluorouracil (5-FU) and 71 to 76% for imiquimod (IMQ). For the treatment of nodular BCC, clearance rates for photodynamic therapy (PDT) were 91% at 3 months, with a sustained lesion clearance response rate of 76% after 5 years of follow-up. Clearance rates were 53 to 76% with IMQ. For squamous cell carcinoma in situ, clearance rates ranged from 52 to 98% for PDT, 67 to 92% for 5-FU, and 75 to 93% for IMQ. For MIS, clearance rates ranged from 53 to 92% for IMQ. For EMPD, 54% of 110 patients in cohort studies and case series had a clinical complete response with IMQ. While surgical intervention remains the standard of care for skin cancer, non-invasive, self-administered topical treatments are highly desirable alternative options. Ultimately, the patient and provider should find a treatment modality that aligns with the patient's expectations and maintenance of quality of life.

A Review of Existing Therapies for Actinic Keratosis: Current Status and Future Directions

Actinic keratosis (AK) is a chronic skin disease in which clinical and subclinical cutaneous lesions coexist on sun-exposed areas such as the head and neck region and the extremities. The high prevalence of AK means the disease burden is substantial, especially in middle-aged and elderly populations. Evidence indicates that AK may progress into invasive cutaneous squamous cell carcinoma, so the European guidelines recommend treatment of any AK regardless of clinical severity. Given the aging population and therefore the increasing incidence of AK and cutaneous field carcinogenesis, further updates on the long-term efficacy of current therapies and new investigational agents are critical to guide treatment choice. Patients often have difficulty adequately applying topical treatments and coping with adverse local skin reactions, leading to less than optimum treatment adherence. The development of associated local skin symptoms and cosmetic outcomes for the area of interest are also relevant to the choice of an appropriate therapeutic strategy. Treatment is always individually tailored according to the characteristics of both patients and lesions. This review focuses on the therapeutic approaches to AK and illustrates the currently available home-based and physician-managed treatments.

Comparative Efficacy and Safety of Tirbanibulin for Actinic Keratosis of the Face and Scalp in Europe: A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials

Actinic keratosis (AK) is a chronic skin condition that may progress to cutaneous squamous cell carcinoma. We conducted a systematic review of efficacy and safety for key treatments for AK of the face and scalp, including the novel 5-day tirbanibulin 1% ointment. MEDLINE, PubMed, Embase, Cochrane Library, clinical trial registries and regulatory body websites were searched. The review included 46 studies, of which 35 studies included interventions commonly used in Europe and were sufficiently homogenous to inform a Bayesian network meta-analysis of complete clearance against topical placebo or vehicle. The network meta-analysis revealed the following odds ratios and 95% credible intervals: cryosurgery 13.4 (6.2–30.3); diclofenac 3% 2.9 (1.9–4.3); fluorouracil 0.5% + salicylic acid 7.6 (4.6–13.5); fluorouracil 4% 30.3 (9.1–144.7); fluorouracil 5% 35.0 (10.2–164.4); imiquimod 3.75% 8.5 (3.5–22.4); imiquimod 5% 17.9 (9.1–36.6); ingenol mebutate 0.015% 12.5 (8.1–19.9); photodynamic therapy with aminolevulinic acid 24.1 (10.9–52.8); photodynamic therapy with methyl aminolevulinate 11.7 (6.0–21.9); tirbanibulin 1% 11.1 (6.2–20.9). Four sensitivity analyses, from studies assessing efficacy after one treatment cycle only, for ≤25 cm² treatment area, after 8 weeks post-treatment, and with single placebo/vehicle node confirmed the findings from the base case. Safety outcomes were assessed qualitatively. These results suggest that tirbanibulin 1% offers a novel treatment for AK, with a single short treatment period, favourable safety profile and efficacy, in line with existing topical treatments available in Europe.

Intensity of Local Skin Reactions During 5-Fluorouracil Treatment Related to the Number of Actinic Keratosis Lesions: A Post Hoc, Exploratory Analysis

INTRODUCTION

Actinic keratoses (AK) are epithelial lesions caused by chronic skin exposure to ultraviolet light that can progress into squamous cell carcinoma. Although several treatments are effective, they are associated with severe skin reactions, which might be related to the extent of the disease. This study aimed to examine the relationship between the severity of local skin reactions during treatment with 5-fluorouracil 4% cream and the number of AK lesions at baseline.

METHODS

This post hoc analysis pooled data from two multicentre randomised phase III studies (HD-FUP3B-048, HD-FUP3B-049) in patients with AK treated with topical 5-fluorouracil 4% once daily (OD) or 5% twice daily (BID) for 4 weeks. First, we compared the severity, assessed using a numerical rating scale, of the local skin reactions between 5-fluorouracil 4% and 5%. Then, we investigated the relationship between the number of lesions at baseline and severe skin reactions with 5-fluorouracil 4% OD.

RESULTS

Safety data were included from 397 patients who had received 5-fluorouracil 4% (348 in study HD-FUP3B-048, 49 in study HD-FUP3B-049) OD and 342 (HD-FUP3B-048) who had received 5-fluorouracil 5% BID. For most skin reactions, severe ones were more common in patients treated with 5-fluorouracil 5% cream BID than in those treated with 5-fluorouracil 4% cream OD (P < 0.05). With 5-fluorouracil 4% OD, the incidence of severe erythema was significantly higher in patients with at least 10 lesions (46%) than in patients with 5-10 lesions (28%; P < 0.001). Similar results were observed for the other local skin reactions.

CONCLUSION

Treatment with 5-fluorouracil 4% cream OD was associated with less severe local skin reactions than 5-fluorouracil 5% BID. The number of AK lesions at baseline seems to have predictive value regarding the severity of local skin reactions that appear during treatment.

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.

Evaluation of Long-term Clearance Rates of Interventions for Actinic Keratosis: A Systematic Review and Network Meta-analysis

Importance

Multiple interventions are available for the treatment of actinic keratosis (AK). However, most randomized clinical trials and meta-analyses focus on short-term efficacy outcomes.

Objective

To investigate and synthesize the long-term efficacy (≥12 months) of interventions for AK from parallel-arm randomized clinical trials.

Data Sources

Searches in MEDLINE, Embase, and Central were conducted from inception until April 6, 2020. The reference lists of the included studies and pertinent trial registers were hand searched. The study was completed February 27, 2021.

Study Selection

Two reviewers screened the titles and abstracts of 2741 records. Finally, 17 published reports (original studies and follow-up reports) referring to 15 independent randomized clinical trials with an overall sample size of 4252 patients were included.

Data Extraction and Synthesis

Two reviewers independently extracted data on study, patient, and intervention characteristics. Network meta-analysis (NMA) of each outcome was conducted with a frequentist approach. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) guidance for NMA was used to assess the certainty of evidence. The revised Cochrane risk-of-bias tool for randomized clinical trials was used to evaluate the methodologic quality.

Main Outcomes and Measures

Participant complete clearance, participant partial clearance, and lesion-specific clearance were the outcomes, with each assessed at least 12 months after the end of treatment.

Results

Data from 15 independent randomized clinical trials including 4252 patients were extracted and synthesized. Ten studies were included in an NMA for the outcome of participant complete clearance, with photodynamic therapy with aminolevulinate (ALA-PDT) showing the most favorable risk ratio (RR) compared with placebo (RR, 8.06; 95% CI, 2.07-31.37; GRADE, moderate), followed by imiquimod, 5% (RR, 5.98; 95% CI, 2.26-15.84; GRADE, very low), photodynamic therapy with methyl aminolevulinate (MAL-PDT) (RR, 5.95; 95% CI, 1.21-29.41; GRADE, low), and cryosurgery (RR, 4.67; 95% CI, 1.36-16.66; GRADE, very low). Similarly, ALA-PDT had the highest RR in the NMA for lesion-specific clearance (RR, 5.08; 95% CI, 2.49-10.33; GRADE, moderate). No NMA was possible for participant partial clearance owing to poor reporting of this outcome.

Conclusions and Relevance

This systematic review and network meta-analysis found that therapy including ALA-PDT, imiquimod, 5%, MAL-PDT, and cryosurgery was associated with significant long-term efficacy in the NMA. This study provides data for a possible use in an evidence-based framework for selecting interventions with sustained lesion clearance.

Field cancerization: Treatment

The goal of field cancerization treatment is to reduce the risk of developing keratinocyte carcinoma. Selecting the appropriate therapy depends on the degree of field cancerization and the number of invasive cutaneous squamous cell carcinomas. Other considerations include treatment efficacy, cost, side effects, and patient preference. Field therapies are preferred because they address clinically visible disease and subclinical atypia. However, lesion-directed therapies are useful for lesions that are more difficult to treat or those where a histologic diagnosis is required. Patients with extensive field cancerization benefit from a combination of field-directed and lesion-directed treatments. The second article in this continuing medical education series provides a framework to guide evidence-based decision making for field cancerization treatment.