A pharmacokinetic evaluation of 0.5% and 5% fluorouracil topical cream in patients with actinic keratosis

Poor Adherence to Self-Applied Topical Drug Treatment Is a Common Source of Low Lesion Clearance in Patients with Actinic Keratosis-A Cross-Sectional Study

BACKGROUND

Many treatments for actinic keratosis (AK) have been proven efficient in clinical trials. However, patients with AK may still experience unsatisfactory therapeutic outcomes in clinical practice.

OBJECTIVES

To investigate patient adherence to self-applied topical interventions for AK and to explore factors associated with adherence in a real-world setting.

METHODS

A cross-sectional study was conducted. Patients presenting with AK were asked to complete a self-administered questionnaire about their last topical AK treatment.

RESULTS

A total of 113 patients participated with a median age of 78.5 years (range 58-94). Fifty-four patients (47.8%) received topical diclofenac, ten (8.8%) imiquimod, nine (8%) 5-fluorouracil, nine (8%) 5-fluorouracil plus salicylic acid, and eight (7.1%) photodynamic therapy. The non-adherence rate was 46.9% (n = 53), and only 30.9% (n = 35) used the topical treatments according to the summary of product characteristics (SmPC). These subgroups were compared. Patients of the non-compliant group were significantly less informed about the application time of the specific topical intervention (p = 0.002) and adjusted the timeframe (p < 0.001) and application frequency of the therapy (p = 0.02) independently of their physician. Conversely, patients reporting a sufficient pre-treatment consultation (p = 0.019) generally complied with the SmPC compliance application.

CONCLUSIONS

A thorough pre-treatment consultation can help to increase treatment adherence and ensure lesion clearance.

Fabrication and optimization of electrospun polymeric nanofibers loaded with 5-fluorouracil and rosemary extract

BACKGROUND

Topical 5-fluorouracil [5FU] is one of the mostly prescribed medications for different types of skin cancer; however, it is associated with drug resistance and adverse effects. Rosemary extract has promising dose-dependent antitumor effects, as well as a synergistic effect in combination with 5-fluorouracil besides sensitizing the 5-FU-resistant cells.

OBJECTIVE

Polymeric nanofibers loaded with 5FU and rosemary extract were optimized to combine both ingredients in one controlled release drug delivery system, aiming to enhance the efficacy while retaining the adverse effects.

METHOD

Polymeric nanofibers loaded with 5-FU and rosemary were fabricated via electrospinning technique. Design expert software was utilized to study the effect of independent variables including polymer concentration, voltage, and feeding rate on the characteristics of the resulting nanofibers. Afterwards, the FTIR spectrum and release kinetic of the drug and extract from the optimized nanofibers and their cytotoxic effect against A375 cell line were investigated.

RESULTS

The formulation composed of 6.65% PVA electrospun at 1 mL.h-1 and 17.5kV was chosen as the optimum fabrication condition. The mean diameter of the optimized nanofibers was 755 nm. The drug and rosemary extract contents were 75.38 and 93.42%, respectively. The fabrication yield was 100%, bioadhesion force was 1.28 N, and bead abundance was 10 per field. The cytotoxicity of the optimized formulation was significantly higher than the control groups.

CONCLUSION

According to the appropriate loading percent, release efficiency and release kinetics, bioadhesion force, and cytotoxicity, these nanofibers could be further investigated as a topical treatment option to increase the efficacy of 5-FU.

Short-Term Follow-Up of a Randomized Controlled Trial of 0.5% and 5% 5-Fluorouracil After Microneedling for Treatment of Facial Actinic Keratoses

INTRODUCTION

Topical 5-fluorouracil (5-FU) is used to treat actinic keratosis, although side effects limit treatment. Microneedling might be a tool for reducing treatment duration.

OBJECTIVE

To evaluate microneedling to promote 5-FU delivery at different concentrations (0.5% and 5%) for actinic keratoses (AKs) treatment.

METHODS

Forty-four patients with facial AKs subjected to 1.0 mm microneedling on 1 side of the face were randomized into 5% 5-FU or 0.5% 5-FU groups. Evaluations of efficacy and safety were conducted on days 21 and 111.

RESULTS

Forty-four patients aged 47 to 85 years were enrolled. Complete clearance of AKs was similar within groups for the side of the face treated with microneedling and 5-FU and the side treated with 5-FU alone in both the 5% and 0.5% 5-FU groups. Microneedling and 5% 5-FU was superior to microneedling and 0.5% 5-FU to reduce AKs (p = .025). Microneedling and 5% 5-FU resulted in fewer adverse effects than 5% 5-FU alone (p = .011).

CONCLUSION

Topical 5% and 0.5% 5-FU delivery for 3 days after microneedling was effective for treating facial AKs and equivalent to 5% and 0.5% 5-FU alone for 15 days after 3 months of follow-up. Microneedling may potentiate 5-FU treatment, reducing treatment time without losing efficacy.

Therapeutic application of microsponges based drug delivery system

Microsponges delivery system (MDS) is highly porous, cross-linked based polymeric systems, that activates in the presence of temperature, rubbing and pH. MDS offers wide range of advantage, like controlled drug release, site-specific action, stable over a broad range of pH, poor irritation, cost effective, improved patient compliance. They can be transformed into various dosage forms like creams, gels, and lotions. MDS based system are suitable for treatment of topical disorders like acne, psoriasis, dandruff, eczema, scleroderma, hair loss, skin cancer, and other dreadful diseases. MDS application for drug delivery is not limited to topical drug delivery but also explored for oral, parenteral and pulmonary drug delivery. Microsponges were studied for colon targeting of drugs and genes. Additionally, MDS has wide application for sunscreen, cosmetics, and over the counter (OTC) products. Furthermore, MDS does not actuate any irritation, genotoxicity, immunogenicity or cytotoxicity. Therefore, this review extensively highlights about microsponges, their advantages, key factors affecting the micro-sponges' characteristics, the therapeutic application of microsponges in topical disorders, cancer, as cosmetics, recent advances in MDS and addresses the associated challenges.

Skin cancer therapeutics: nano-drug delivery vectors—present and beyond

Background

Skin cancers are among the widely prevalent forms of cancer worldwide. The increasing industrialization and accompanied environmental changes have further worsened the skin cancer statistics. The stern topical barrier although difficult to breach is a little compromised in pathologies like skin cancer. The therapeutic management of skin cancers has moved beyond chemotherapy and surgery.

Main body of the abstract

The quest for a magic bullet still prevails, but topical drug delivery has emerged as a perfect modality for localized self-application with minimal systemic ingress for the management of skin cancers. Advances in topical drug delivery as evidenced by the exploration of nanocarriers and newer technologies like microneedle-assisted/mediated therapeutics have revolutionized the paradigms of topical treatment. The engineered nanovectors have not only been given the liberty to experiment with a wide-array of drug carriers with very distinguishing characteristics but also endowed them with target specificity. The biologicals like nucleic acid-based approaches or skin penetrating peptide vectors are another promising area of skin cancer therapeutics which has demonstrated potential in research studies. In this review, a panoramic view is presented on the etiology, therapeutic options, and emerging drug delivery modalities for skin cancer.

Short conclusion

Nanocarriers have presented innumerable opportunities for interventions in skin cancer therapeutics. Challenge persists for the bench to bedside translation of these highly potential upcoming therapeutic strategies.

Graphic abstract

A review of emerging and non-US FDA-approved topical agents for the treatment of basal cell carcinoma

Although surgical therapy continues to be the gold standard for the treatment of basal cell carcinoma given high cure rates and the ability to histologically confirm tumor clearance, there are a number of nonsurgical treatment options that may be considered based on individual tumor characteristics, functional and cosmetic considerations, patient comorbidities and patient preference. Topical 5-fluorouracil 5% cream and imiquimod 5% cream have been US FDA-approved for the treatment of superficial basal cell carcinoma. Additionally, a number of new and emerging topical agents and techniques have been described for the treatment of basal cell carcinoma and will be reviewed herein.

Safety of topical interventions for the treatment of actinic keratosis

Introduction: Actinic keratosis (AK) are proliferations of atypical keratinocytes that may eventually progress to cutaneous squamous cell carcinoma. Therefore, AK requires consequent and early treatment. Areas covered: A variety of effective approaches is currently available for the clearance of AK. These interventions may be applied either in a lesion-directed or field-directed mode as AK can occur as single or multiple lesions. Field-directed approaches typically comprise topical drug-mediated interventions which aim at eliminating all visible lesions and also at clearing subclinical changes of the actinically damaged field. However, most treatment options are associated with local adverse events such as erythema, scaling, pain, and rarely with systemic symptoms. This expert review provides a comprehensive and up-to-date overview of the safety considerations of the commonly prescribed topical treatment agents cyclooxygenase inhibitors, 5-fluorouracil, imiquimod, ingenol mebutate, and photodynamic therapy. All these therapies have been proven efficient, yet they differ considerably regarding their safety profile. Expert opinion: In the future, safety concerns will relate to long-term and irreversible adverse drug events instead of application site reactions. In particular, the rate of treatment-associated non-melanoma skin cancers will increasingly come into focus and warrant investigation in postmarketing surveillance trials with a long-term follow-up.

Topical 5-fluorouracil in dermatologic disease

BACKGROUND

5-fluorouracil (5-FU) has proven to be an effective therapy in the treatment of a variety of dermatologic conditions. Approved by the United States Food and Drug Administration for the treatment of actinic keratoses and superficial basal cell carcinoma, topical 5-FU has also demonstrated efficacy in the treatment of a variety of other dermatologic diseases.

METHODS

A search of the MEDLINE standard computer database, MEDLINE advanced database, and EMBASE database was conducted.

RESULTS

Thirty-four articles met criteria for inclusion in this review. These articles represented 16 randomized controlled trials and 18 case series. Each article was reviewed and summarized.

CONCLUSIONS

Topical 5-FU is used in a variety of dermatologic disease processes with a wide range of efficacy and levels of evidence. Based on extent and level of evidence, our disease-specific systematic review found that the evidence is strongest for topical 5-FU use in the treatment of actinic keratosis, squamous cell carcinoma, and basal cell carcinoma. This review serves as a comprehensive summary of topical 5-FU use in dermatology.

Topical 5-Fluorouracil associated skin reaction

Topical 5- Fluorouracil (5-FU) is used more frequently to treat actinic keratosis. We are presenting a skin reaction as a side effect of this medication. Treatment for such cases of 5-FU-induced skin reactions is based on proper skin care and treatment of any superimposed infections. Medical providers should be aware of such side effects to provide their patients with proper instructions to avoid complications.

Fractional laser-assisted topical delivery leads to enhanced, accelerated and deeper cutaneous 5-fluorouracil uptake

BACKGROUND

Topical 5-Fluorouracil (5-FU) exhibits suboptimal efficacy for non-melanoma skin cancer, attributed to insufficient intracutaneous penetration. This study investigates the impact of ablative fractional laser (AFXL) at different laser-channel depths on cutaneous 5-FU pharmacokinetics and biodistribution.

METHODS

In vitro porcine skin underwent AFXL-exposure using a fractional 10,600 nm CO₂-laser, generating microscopic ablation zones (MAZ) reaching the dermoepidermal junction (MAZ-ED), superficial-(MAZ-DS), or mid-dermis(MAZ-DM). 5-FU in AFXL-exposed and control skin was measured in Franz diffusion cells at 4 and 24 hours (n = 55). HPLC quantified 5-FU in full-thickness skin, specific skin depths of 100μm-1500μm, and transcutaneous receiver-compartments. Qualitative matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) visualized 5-FU in selected samples.

RESULTS

Overall, AFXL enhanced and accelerated 5-FU uptake versus unexposed controls, with increased accumulation in deep skin layers (p < 0.01). While total, 24-hour 5-FU uptake in control skin was 0.096 mg/cm³ (0.19% of applied concentration), AFXL delivered up to 4.707 mg/cm³ (MAZ-DM; 9.41% uptake, 49-fold enhancement) (p = 0.002; 24 hours). Indicating accelerated delivery, 5-FU in laser-exposed samples at 4 hours was at least 10-fold that of 24-hour controls (p = 0.002). Deeper laser-channels increased delivery throughout the skin (MAZ-ED vs. MAZ-DM; p<0.01). MALDI-MSI confirmed enhanced, accelerated, deeper and more uniform 5-FU distribution after AFXL versus controls.

CONCLUSIONS

AFXL offers laser-channel depth-dependent, enhanced and accelerated 5-FU uptake, with increased deposition in deep skin layers.

A Way Forward for Cancer Chemoprevention: Think Local

As cells progress through carcinogenesis, the associated exponential expansion of genetic and molecular aberrations and resultant heterogeneity make therapeutic success increasingly unattainable. Therapeutic intervention at early stages of carcinogenesis that occurs within the primary organ and in the face of a lower burden of molecular aberrations, constitutes a basic tenet of cancer chemoprevention, and provides a situation that favors a greater degree of therapeutic efficacy compared with that of advanced cancer. A longstanding barrier to chemoprevention relates to the requirement for essentially no systemic toxicity, and the fact that when large numbers of people are treated, the emergence of systemic toxicity is almost universal. A rational means to address this in fact relates to a second basic tenet of the chemopreventive strategy: the focus of therapeutic intervention is to disrupt a process that is in essence localized to a single organ. Based upon this consideration, a strategy which is based upon local delivery of therapeutics to an at-risk organ will achieve therapeutic efficacy while avoiding systemic delivery and its associated toxicity. This article will review the rationale for undertaking such an approach, describe successful clinical achievements based on this strategy, describe ongoing efforts to expand the impact of this approach, and together will highlight the high impact that this approach has already had on the field as well as its extremely high potential for future impact. Cancer Prev Res; 10(1); 14-35. ©2016 AACR.

Evaluation of the Effectiveness of Imiquimod and 5-Fluorouracil for the Treatment of Actinic Keratosis: Critical Review and Meta-Analysis of Efficacy Studies

Background:

Actinic keratosis lesions occur frequently on sun-exposed skin of Caucasians. They become more prevalent with advancing age and are important in identifying the risk factor of those people possibly predisposed to invasive squamous cell carcinoma. Topical therapies are useful alternatives to cryotherapy for treating diffuse actinic damage and a number of preparations have been developed for treating actinic keratosis.

Objectives:

A cumulative meta-analysis was performed to determine the efficacy of imiquimod 5% cream, which presents a new alternative topical therapy for actinic keratosis, and to compare it to 5-fluorouracil for the treatment of actinic keratosis lesions of the face and scalp.

Methods:

We searched MEDLINE (1966 to October 2004) for relevant studies evaluating the efficacy of actinic keratosis topical agents imiquimod and 5-fluorouracil (0.5%, 1%, and 5%). Studies included in this meta-analysis required a dosage regimen that was not significantly different from that approved by Health Canada and the U.S. FDA. Studies also required a well-defined treatment duration and followup period, with the primary efficacy variable being the complete (100%) clearance of all actinic keratosis lesions defined as the proportion of patients at followup with no clinically visible lesions in the treatment area. To determine the average efficacy rate for both drugs, the data from each study were combined for that drug.

Results:

Ten studies were included in the analysis. The average efficacy rate for each drug (with 95% confidence interval) was 5-fluorouracil, 52 ± 18% ( n = 6 studies, 145 subjects) and imiquimod, 70 ± 12% ( n = 4 studies, 393 subjects).

Conclusions:

The results of this meta-analysis show that both imiquimod and 5-fluorouracil are effective methods for the treatment of actinic keratosis and provide a useful alternative to cryotherapy. However, this analysis suggests that imiquimod may have higher efficacy than 5-fluorouracil for actinic keratosis lesions located on the face and scalp and therefore provides another option to dermatologists.

Topical therapies for skin cancer and actinic keratosis

The global incidence of skin cancer and actinic keratosis (AK) has increased dramatically in recent years. Although many tumours are treated with surgery or radiotherapy topical therapy has a place in the management of certain superficial skin neoplasms and AK. This review considers skin physiology, non-melanoma skin cancer (NMSC), the relationship between AK and skin cancer and drugs administered topically for these conditions. The dermal preparations for management of NMSC and AK are discussed in detail. Notably few studies have examined drug disposition in cancerous skin or in AK. Finally, recent novel approaches for targeting of drugs to skin neoplasms and AK are discussed.

Spanish adaptation of the European guidelines for the evaluation and treatment of actinic keratosis

Current trends in our setting indicate that the prevalence of actinic keratosis and similar diseases will increase in coming years and impose a greater burden on health care resources. A long list of clinical features must be taken into account when approaching the treatment of actinic keratosis. Until recently, therapeutic approaches focused solely on ablative procedures and the treatment of individual lesions and did not take into account areas of field cancerization. Now that the therapeutic arsenal has grown, standardized criteria are needed to guide the optimal choice of treatment for each patient. The elaboration of evidence-based consensus recommendations for the diagnosis and treatment of actinic keratosis generates knowledge that will help clinicians to deliver the highest level of care possible, standardizing decision-making processes and enhancing awareness among all the health professionals involved in the care pathway.

Randomized, vehicle-controlled trials of topical 5-fluorouracil therapy for actinic keratosis treatment: an overview

Actinic keratoses are common in older individuals and topical immunotherapy is an important treatment when multiple lesions are present. To assess the efficacy of 5-fluorouracil in treating actinic keratoses, a systematic review of randomized, vehicle-controlled trials was performed. Percentages of 5-fluorouracil and vehicle responders were determined by absolute clearance and mean percent reduction in lesion count. Four trials with 399 and 269 participants in active treatment and vehicle groups, respectively, were evaluated. After 4 weeks of treatment, total clearance and mean lesion count reduction were 52.6 and 90.2% in the treatment group versus 0.85 and 28.3% in the vehicle group, respectively. Topical 5-fluorouracil is efficacious in treating actinic keratoses; however, vehicle responses warrant further investigation of study design and disease severity scales.

[Efficacy and risks of topical 5-fluorouracil in Darier's disease]

BACKGROUND

Darier's disease, an autosomal dominant disorder, is often resistant to therapy. There have been few encouraging reports in recent years of treatment using topical 5-fluorouracil (5FU) in this indication. We describe three cases of Darier's disease treated with Efudix: though it initially proved very effective, after several months this treatment became inefficacious.

PATIENTS AND METHODS

Case 1: a 16-year-old girl with Darier's disease refractory to conventional treatments. Treatment with topical 5FU was initiated. After 3 weeks, her cutaneous lesions had practically disappeared, leaving only pigmented scars. At 6 months, worsening of the disease was controlled by increasing 5FU. At 11 months, the disease worsened and 5FU, which proved inefficient, was stopped. Case 2: a 59-year-old woman presenting treatment-resistant Darier's disease was given 5FU. After 1 week, improvement began and was evident at 4 months. However, after 13 months of treatment, the disease progressed, and increased 5FU proved completely ineffective. Case 3: a 29-year-old woman was hospitalized for inflammatory Darier's disease. Topical 5FU was applied to the left half of the body and a short course of oral corticosteroids was prescribed. After 10 days of treatment, there was a clear improvement. After 6 weeks, the patient showed episodes of healthy skin. However after 3 months, the patient stopped taking her treatment due to inefficacy.

DISCUSSION

While topical 5FU seems to be effective initially in treating Darier's disease, this efficacy subsides over time. Although no adverse effects were noted in our patients, use of 5FU can result in serious adverse reactions. Because of the loss of efficacy of this treatment following initial success, coupled with its poorly evaluated safety, caution must be exercised when prescribing it, particularly in patients with dihydropyriminidine dehydrogenase (DPD) deficiency or for use on damaged skin.

5% 5-Fluorouracil cream for treatment of verruca vulgaris in children

Warts are a common pediatric skin disease. Most treatments show only modest benefit, and some are poorly tolerated because of pain. 5-fluorouracil interferes with deoxyribonucleic acid and ribonucleic acid synthesis, and is used to treat genital warts in adults. Efficacy, safety, and tolerability of topical 5% 5-fluorouracil for treatment of common warts were examined in an open-label pilot study with pediatric patients. Thirty-nine children who have at least two hand warts applied 5% 5-fluorouracil cream (Efudex, Valeant Pharmaceuticals International) once or twice daily, under occlusion for 6 weeks. Assessment of treatment response and side effects was performed at baseline, treatment completion, and 3- and 6-month follow-ups. Hematology measures, liver function tests, and medication blood levels were reassessed at treatment completion. Eighty-eight percent of treated warts improved after 6 weeks of treatment, and 41% of subjects had complete resolution of at least one wart. Treatment response did not differ between once or twice daily applications. Tolerability and patient satisfaction were excellent. No subject had clinically significant blood levels of 5-fluorouracil. At 6 month follow-up, 87% of complete responders had no wart recurrence. Topical 5% 5-fluorouracil is a safe, effective, and well-tolerated treatment for warts in children.

Treatment options for premalignant and malignant cutaneous tumors

Whenever possible, surgical excision of skin cancers should be the gold standard of treatment. There are many considerations when choosing one treatment modality over another. These include the lesion's location, the surgeon's experience and comfort level, the patient's health status and their potential compliance, access to available technology, and economic considerations for the patient and the provider. Regardless of the type of therapy, all forms of treatment share the following goals: complete disease cure, preservation of normal tissue, preservation of function, and optimal cosmesis.

Evaluation of the effectiveness of imiquimod and 5-fluorouracil for the treatment of actinic keratosis: Critical review and meta-analysis of efficacy studies

BACKGROUND

Actinic keratosis lesions occur frequently on sun-exposed skin of Caucasians. They become more prevalent with advancing age and are important in identifying the risk factor of those people possibly predisposed to invasive squamous cell carcinoma. Topical therapies are useful alternatives to cryotherapy for treating diffuse actinic damage and a number of preparations have been developed for treating actinic keratosis.

OBJECTIVES

A cumulative meta-analysis was performed to determine the efficacy of imiquimod 5% cream, which presents a new alternative topical therapy for actinic keratosis, and to compare it to 5-fluorouracil for the treatment of actinic keratosis lesions of the face and scalp.

METHODS

We searched MEDLINE (1966 to October 2004) for relevant studies evaluating the efficacy of actinic keratosis topical agents imiquimod and 5-fluorouracil (0.5%, 1%, and 5%). Studies included in this meta-analysis required a dosage regimen that was not significantly different from that approved by Health Canada and the U.S. FDA. Studies also required a well-defined treatment duration and followup period, with the primary efficacy variable being the complete (100%) clearance of all actinic keratosis lesions defined as the proportion of patients at followup with no clinically visible lesions in the treatment area. To determine the average efficacy rate for both drugs, the data from each study were combined for that drug.

RESULTS

Ten studies were included in the analysis. The average efficacy rate for each drug (with 95% confidence interval) was 5-fluorouracil, 52 +/- 18% (n = 6 studies, 145 subjects) and imiquimod, 70 +/- 12% (n = 4 studies, 393 subjects).

CONCLUSIONS

The results of this meta-analysis show that both imiquimod and 5-fluorouracil are effective methods for the treatment of actinic keratosis and provide a useful alternative to cryotherapy. However, this analysis suggests that imiquimod may have higher efficacy than 5-fluorouracil for actinic keratosis lesions located on the face and scalp and therefore provides another option to dermatologists.

Total body topical 5-fluorouracil for extensive non-melanoma skin cancer

Background

Topical 5-fluorouracil 5% cream is one of␣the treatment modalities for non-melanoma skin cancer (NMSC). There is a lack of suitable therapies to treat patients with extensive NMSC. In this paper we report two patients with extensive NMSC treated by total body application of topical 5-fluorouracil 5% cream.

Observations

Topical 5-fluorouracil 5% cream was applied twice daily to the total body, including normal appearing skin. During the treatment, weekly blood samples were taken for measurement of 5-fluorouracil levels. All samples showed a 5-fluorouracil level less than the detection level of 10 µg/l. Total body 5-fluorouracil 5% cream was shown to be an effective treatment in our patients; the majority of lesions cleared in both patients.

Conclusions

In conclusion, total body topical 5-fluorouracil 5% cream application was successful in two patients with extensive NMSC. No detectable serum level of 5-fluorouracil could be determined. Pain and secondary infections were important side effects in our patients. However, in patients with extensive NMSC this treatment may be considered.

Nonmelanoma skin cancer

Therapy for basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) does not end with treatment of the initial lesion because almost 50% of patients with one nonmelanoma skin cancer (NMSC) develop another NMSC in the next 5 years. An integrated program of skin cancer awareness, sun protection, and prophylactic approaches is critical. The risk profile of the tumor influences which therapies and specialties will be involved. Most NMSCs may be treated with outpatient methods. Primary care physicians may treat low-risk tumors, but dermatologists specially trained in cutaneous oncology and a multidisciplinary team should manage high-risk lesions. Superficial BCC and SCC may be treated adequately with superficial modalities such as electrodesiccation and curettage (EDC) and cryotherapy. Topical 5-fluorouracil is effective for small in situ lesions. Invasive but low-risk lesions may be treated with EDC and cryotherapy provided that the tumor is limited to the papillary dermis, is not recurrent, and does not have high-risk features. High-risk tumors are best treated with excision and histologic examination or Mohs micrographic surgery (MMS). MMS is the therapeutic gold standard for all NMSCs in terms of cure rates, margin control, and tissue conservation. Because of its higher cost and specialized process, MMS is best reserved for specific indications.

Evaluation of the efficacy and tolerability of 0.5% fluorouracil cream and 5% fluorouracil cream applied to each side of the face in patients with actinic keratosis

BACKGROUND

A new 0.5% fluorouracil cream has been developed that provides an alternative to the more highly concentrated topical formulations of fluorouracil that are currently available.

OBJECTIVE

This was a comparison of the tolerability and efficacy of the 0.5% and 5% fluorouracil creams in the treatment of actinic keratosis (AK).

METHODS

During this single-blind, randomized study, patients with > or =6 AK lesions were treated for 4 weeks with the 0.5% (once daily) and 5% (twice daily) fluorouracil creams applied to opposite sides of the face. After the end of treatment, patients were followed for an additional 4 weeks. Efficacy variables included absolute and percent reductions in AK lesions from baseline and total clearance of AK lesions. A questionnaire was used to evaluate patients' treatment preferences. Tolerability was evaluated through continuous monitoring of adverse events.

RESULTS

Treatment with 0.5% fluorouracil cream reduced the number of AK lesions from 11.3 at baseline to 2.5 at the end of the 4-week follow-up phase, compared with a reduction from 10.3 to 4.2 lesions after treatment with 5% fluorouracil cream. The reduction was significantly greater with the 0.5% cream compared with the 5% cream (P = 0.044). The 0.5% cream was as effective as the 5% cream in terms of the percent reduction in AK lesions from baseline (67% and 47%, respectively) and in achieving total clearance of AK lesions (both treatments, approximately 43% of patients). Both treatments were associated with similar degrees of investigator-rated irritation; however, patients preferred the 0.5% cream because they felt it was more tolerable (P = 0.003), easier to apply, and had a once-daily application schedule. Although all patients experienced facial irritation in association with both creams, fewer patients treated with the 0.5% cream reported symptoms of facial irritation.

CONCLUSIONS

In this study, 0.5% fluorouracil cream once daily was at least as effective as 5% fluorouracil cream twice daily in terms of the percent reduction in AK lesions and total clearance of AK lesions; it was more effective than the 5% cream in reducing the absolute number of AK lesions from baseline. Patients preferred the 0.5% cream to the 5% cream.

A comparison of the skin permeation of three topical 0.5% fluorouracil formulations with that of a 5% formulation

BACKGROUND

Topical fluorouracil has proven efficacy in the treatment of actinic keratosis. The systemic absorption of various topical formulations of fluorouracil varies, however, and may be affected by the concentration and delivery system used.

OBJECTIVE

This study compared the flux and percutaneous absorption of 3H-labeled fluorouracil from three 0.5% fluorouracil formulations incorporated into a porous microsphere delivery system with those from a commercially available 5% fluorouracil formulation.

METHODS

Penetration of all formulations through the skin was sampled every 3 hours for 24 hours using full-thickness human cadaver skin samples mounted in a Bronaugh flow-through diffusion cell apparatus. Total absorption was defined as the sum of the amount of cumulative flux through the skin over 24 hours and the amount retained in the skin at 24 hours.

RESULTS

The flux through the skin of the 5% fluorouracil formulation was 20 to 40 times greater (normalized, 2-4 times greater) than that of the 0.5% fluorouracil formulations. A higher percentage of absorbed fluorouracil was retained in the skin after 24 hours with the 0.5% formulations (86%-92%) than with the 5% formulation (54%).

CONCLUSION

These findings suggest that the 0.5% formulations are associated with less flux through the skin than the 5% formulation and, therefore, potentially less systemic exposure.