5-fluorouracil iontophoretic therapy for Bowen's disease

Electromotive Enhanced Drug Administration in Oncology: Principles, Evidence, Current and Emerging Applications

Local-regional administration of cytotoxic drugs is an important adjunct to systemic chemotherapy amongst cancer patients. It allows for targeted delivery of agents at high concentration to target sites while minimizing systemic side effects. Despite the pharmacokinetic advantages of the local-regional approach, drug transport into tumor nodules remains limited due to the biophysical properties of these tissues. Electromotive enhanced drug administration (EMDA) represents a potential solution to overcome challenges in local drug transport by applying electric currents. Through electrokinetic phenomena of electromigration, electroosmosis and electroporation, electric currents have been shown to improve drug penetration and distribution in a wide variety of clinical applications. Amongst patients with non-muscular invasive bladder cancer (NMIBC) and basal and squamous cell skin cancers, EMDA has been successfully adopted and proven efficacious in several pre-clinical and clinical studies. Its application in ophthalmological and other conditions has also been explored. This review provides an overview of the underlying principles and factors that govern EMDA and discusses its application in cancer patients. We also discuss novel EMDA approaches in pre-clinical studies and explore future opportunities of developments in this field.

Physical drug delivery enhancement for aged skin, UV damaged skin and skin cancer: Translation and commercialization

This review analyses physical drug delivery enhancement technologies with a focus on improving UV damaged skin, actinic keratoses and non-melanoma skin cancer treatment. In recent years, physical drug delivery enhancement has been shown to enhance cosmeceutical and skin cancer treatment efficacy, but there are pros and cons to each approach which we discuss in detail. Mechanisms of action, clinical efficacy, experimental design, outcomes in academic publications, clinical trial reports and patents are explored to evaluate each technology with a critical, translation focused lens. We conclude that the commercial success of cosmeceutical applications, e.g. microneedles, will drive further innovation in this arena that will impact how actinic keratoses and non-melanoma skin cancers are clinically managed.

Selected Medicines Used in Iontophoresis

Iontophoresis is a non-invasive method of systemic and local drug delivery using an electric field. Iontophoresis enables diffusion of the selected drug via skin, mucosa, enamel, dentin, and other tissues. The amount of delivered therapeutic molecules is about 10⁻2000 times greater than conventional forms of delivery. Among other fields, this method is used in dentistry, ophthalmology, otorhinolaryngology, and dermatology. According to related literature, the most important drugs studied or administered by iontophoresis are: Local anesthetics, opioids, steroids, non-steroidal anti-inflammatory drugs, antibacterial drugs, antifungal drugs, antiviral drugs, anticancer drugs, fluorides, and vitamins. The present review covers current available data regarding the selected medicines used in iontophoresis. Furthermore, indications and conditions of iontophoresis application are reviewed.

Use of iontophoresis for the treatment of cancer

Despite major advancements in cancer treatments, there are still many limitations to therapy including off-target effects, drug resistance, and control of cancer-related symptoms. There are opportunities for local drug delivery devices to intervene at various stages of cancer to provide curative and palliative benefit. Iontophoretic devices that deliver drugs locally to a region of interest have been adapted for the treatment of cancer. These devices have shown promise in pre-clinical and clinical studies for retinoblastoma, skin, bladder, and pancreatic cancers. Herein, we review iontophoretic devices used in the management of cancer.

Topical Treatment of Bowen's Disease with 5-Fluorouracil

Background:

Bowen's disease is a common skin cancer. There are many different therapeutic approaches to treatment. Topical 5-Fluorouracil (5-FU) cream has been used for many years and there are many published papers attesting to its effectiveness. However, no papers have presented long-term followup results with biopsy confirmation of cure.

Objectives:

The purpose of this article is to present the long-term findings following the use of this cream in the treatment of Bowen's disease.

Methods:

Twenty-four patients with 26 biopsy-confirmed lesions of Bowen's disease were treated with topical 5-Fluorouracil cream and were followed for periods of up to 10 years. Posttreatment biopsies were performed in most cases.

Results:

Two of the 26 lesions treated topically recurred at some point. The rest were apparently cured.

Conclusion:

The results presented in this article confirm that treatment of Bowen's disease with topical 5-Fluorouracil cream is safe and effective treatment.

Local iontophoretic administration of cytotoxic therapies to solid tumors

Parenteral and oral routes have been the traditional methods of administering cytotoxic agents to cancer patients. Unfortunately, the maximum potential effect of these cytotoxic agents has been limited because of systemic toxicity and poor tumor perfusion. In an attempt to improve the efficacy of cytotoxic agents while mitigating their side effects, we have developed modalities for the localized iontophoretic delivery of cytotoxic agents. These iontophoretic devices were designed to be implanted proximal to the tumor with external control of power and drug flow. Three distinct orthotopic mouse models of cancer and a canine model were evaluated for device efficacy and toxicity. Orthotopic patient-derived pancreatic cancer xenografts treated biweekly with gemcitabine via the device for 7 weeks experienced a mean log2 fold change in tumor volume of -0.8 compared to a mean log2 fold change in tumor volume of 1.1 for intravenous (IV) gemcitabine, 3.0 for IV saline, and 2.6 for device saline groups. The weekly coadministration of systemic cisplatin therapy and transdermal device cisplatin therapy significantly increased tumor growth inhibition and doubled the survival in two aggressive orthotopic models of breast cancer. The addition of radiotherapy to this treatment further extended survival. Device delivery of gemcitabine in dogs resulted in more than 7-fold difference in local drug concentrations and 25-fold lower systemic drug levels than the IV treatment. Overall, these devices have potential paradigm shifting implications for the treatment of pancreatic, breast, and other solid tumors.

Squamous cell carcinoma of the skin: epidemiology, classification, management, and novel trends

Squamous cell carcinoma (SCC) is the second most common non-melanoma skin cancer. It originates from epidermal keratinocytes or adnexal structures (such as eccrine glands or pilosebaceous units). We describe the salient features of cutaneous SCC. We also review novel classification schemes proposed during the last decade which attempt to stratify SCC lesions based on prognosis. Biopsy leads to definitive diagnosis. Treatment includes surgical excision; Mohs micrographic surgery produces excellent cure rates and spares the maximal amount of tissue. Other modalities include electrodessication and curettage, cryosurgery, radiotherapy, topical medications, photodynamic therapy, and systemic therapy. Management and follow-up depend on the risk stratification of individual lesions.

Successful Treatment of Multiple Premalignant and Malignant Lesions in Arsenical Keratosis with a Combination of Acitretin and Intralesional 5-Fluorouracil

A case of arsenical keratosis with multiple lesions of Bowen's disease and squamous cell carcinoma is described. The patient was successfully treated with a combination of acitretin and intralesional 5-fluorouracil. All the lesions resolved after three months of therapy with no side effects and no recurrence during four months of follow-up.

Update on non-melanoma skin cancer and the value of dermoscopy in its diagnosis and treatment monitoring

Dermoscopy has become an integrative part of the clinical examination of skin tumors. This is because it significantly improves the early diagnosis of melanoma and non-melanoma skin cancer (NMSC) including basal cell carcinoma and keratinocyte skin cancer compared with the unaided eye. Besides its value in the noninvasive diagnosis of skin cancer, dermoscopy has also gained increased interest in the management of NMSC. Dermoscopy has been used in the preoperative evaluation of tumor margins, monitoring of the outcomes of topical treatments and post-treatment follow-up. This article provides an update on NMSC with special emphasis on dermoscopy in the diagnosis and management of basal cell carcinoma, actinic keratosis, Bowens' disease and squamous cell carcinoma.

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.

Therapeutic options for Bowen's disease

Multiple therapeutic options are available for treatment of Bowen's disease. The choice of therapy depends on clinical circumstance and medical practitioner experience. Newer therapies have more extensive support from the literature, but more established therapies may be preferred because of accessibility, cost and efficacy. An overview of the current therapeutic options for Bowen's disease is presented.

Guidelines for management of Bowen's disease: 2006 update

This article represents a planned regular updating of the previous British Association of Dermatologists (BAD) guidelines for management of Bowen's disease. They have been prepared for dermatologists on behalf of the BAD. They present evidence-based guidance for treatment, with identification of the strength of evidence available at the time of preparation of the guidelines.

Possible therapeutic use of vasodilator iontophoresis

BACKGROUND

Investigation into the effects of a novel vasodilator delivery method (for the eventual treatment of scleroderma related digital ulceration) on healthy controls is reported. When Raynaud's phenomenon (episodic cold-induced colour changes of the fingers) occurs in the context of scleroderma, it can be extremely severe, leading to ulceration and sometimes gangrene. The current treatment of choice for scleroderma-related critical digital ischaemia and/or ulceration is intravenous prostanoid therapy, necessitating hospitalisation. However, iloprost is often poorly tolerated and may be ineffective.

METHODS

This study utilises a newly designed iontophoresis chamber which has the potential to allow a therapeutic, rather than diagnostic application for vasodilatory iontophoresis. Ten healthy controls underwent whole finger iontophoresis with 1% acetylcholine chloride for 2 min at 100 microA. Iontophoresis with varying treatment times and currents was carried out on a subset of subjects to determine the effect on perfusion increase.

RESULTS

A significant increase in perfusion following iontophoresis was found, compared to the adjacent, untreated finger (P < 0.001). Maximum increase as a percentage from baseline, mean [SD] = 100 [66]%. Both treatment time and current have an approximately linear relationship with perfusion increase.

CONCLUSIONS

Iontophoresis of the whole finger administers drugs locally with no systemic effects and warrants further investigation as a therapy.

Digital syndactylization for the treatment of interdigital squamous cell carcinoma in situ (Bowen disease)

Bowen disease, or squamous cell carcinoma in situ, has been described as a premalignant intraepidermal lesion of the skin. Although more frequently occurring on limbs, interdigital presentation of squamous cell carcinoma in situ in the foot has been rarely reported, likely because of undetected development. Excision has been recommended as the treatment of choice; however, removal of these lesions from intertriginous skin may present few options for skin closure. Interdigital syndactylization may be an acceptable option for the treatment of interdigital manifestations of Bowen disease. The authors present a case of interdigital squamous cell carcinoma in situ successfully treated with excision and digital syndactylization. At the 2-year follow-up, there was no recurrence and no digital deformities.

Topical treatment strategies for non-melanoma skin cancer and precursor lesions

The ability to manage non-melanoma skin cancers and pre-malignant lesions with topical pharmacologic agents is highly compelling. This article examines currently available products and discusses their emerging roles and limitations. These include fluorouracil, diclofenac sodium, imiquimod, and photodynamic therapy.

Iontophoretic drug delivery

The composition and architecture of the stratum corneum render it a formidable barrier to the topical and transdermal administration of therapeutic agents. The physicochemical constraints severely limit the number of molecules that can be considered as realistic candidates for transdermal delivery. Iontophoresis provides a mechanism to enhance the penetration of hydrophilic and charged molecules across the skin. The principal distinguishing feature is the control afforded by iontophoresis and the ability to individualize therapies. This may become significant as the impact of interindividual variations in protein expression and the effect on drug metabolism and drug efficacy is better understood. In this review we describe the underlying mechanisms that drive iontophoresis and we discuss the impact of key experimental parameters-namely, drug concentration, applied current and pH-on iontophoretic delivery efficiency. We present a comprehensive and critical review of the different therapeutic classes and molecules that have been investigated as potential candidates for iontophoretic delivery. The iontophoretic delivery of peptides and proteins is also discussed. In the final section, we describe the development of the first pre-filled, pre-programmed iontophoretic device, which is scheduled to be commercialized during the course of 2004.

Erbium:YAG Laser Pretreatment Accelerates the Response of Bowen's Disease Treated by Topical 5-Fluorouracil

BACKGROUND

Topical 5-fluorouracil (5-FU) is a standard treatment for Bowen's disease. However, its efficacy may be limited by the presence of stratum corneum. The Er:YAG laser has shown a dramatic enhancement effect on the delivery of 5-FU in vitro by ablation of the stratum corneum. The efficacy of laser-assisted delivery of 5-FU has not been tested in human.

OBJECTIVE

To see whether Er:YAG laser pretreatment can improve the efficacy of topical 5-FU in the treatment of Bowen's disease.

METHODS

Three target lesions from a patient with multiple Bowen's disease were selected for a half-side comparison study. The Er:YAG laser was used to remove the cornified layer on one side of each lesion, followed by twice-daily application of 5-FU cream to both sides. Clinical and histologic responses were compared.

RESULTS

Lesions pretreated with the Er:YAG laser showed more rapid clinical and histologic responses to topical 5-FU than those treated with 5-FU alone. Evaluation at 9 months after treatment showed no recurrences of lesions on both sides.

CONCLUSIONS

Our preliminary study demonstrates that this Er:YAG laser-assisted modality is effective and shows accelerated clinical response and shortened treatment time compared with topical 5-FU as a single treatment.

Treatment of squamous cell carcinoma with intralesional 5-Fluorouracil

BACKGROUND

5-Fluorouracil (5-FU) has been used topically and intralesionally to treat lesions related to squamous cell carcinoma (SCC) such as actinic keratosis, Bowen's disease, and keratoacanthoma.

OBJECTIVE

We sought to determine whether intralesional 5-FU might be effective in treating a patient with SCC.

METHODS

A patient with SCC at the junction of the right alar crease and right nasolabial fold was treated with eight weekly injections of 5-FU, with doses ranging from 0.8 to 2.4 mL.

RESULTS

A repeat biopsy after the eighth treatment showed total clearance of the cancer, and the patient has remained free of recurrence during a 5-month follow-up period.

CONCLUSION

This modality may provide patients with SCC in cosmetically important locations or in areas that require complex surgery the advantage of a nonsurgical cure.

Bowenoid papulosis of the vulva-immunotherapeutical approach with topical imiquimod

INTRODUCTION

Bowenoid papulosis is a characteristic lesion of the ano-genital region and represents a form of squamous cell carcinoma in situ, very often associated to the oncogenic high-risk human papilloma virus (HPV) types 16, 18, 31 and 33. Therapies applied so far, in general, show high rates of relapse, and patients complain of pruritus and pain. Imiquimod cream is a topical immune response modifier with indirect antiviral and antitumor effects through the stimulation of local cytokine production and cell-mediated immune response.

CASE REPORT

In the present paper we report on the topical application of imiquimod cream in a woman with a high-risk HPV-associated vulvar intraepithelial neoplasia grade III (VIN III) of the vulva.

DISCUSSION

In addition a review of the literature is given.

Imiquimod 5% cream in the treatment of Bowen's disease

BACKGROUND

Large-diameter lesions of Bowen's disease at sites such as the shin may be difficult to treat surgically and may require alternate treatment modalities.

OBJECTIVE

We investigated whether imiquimod 5% cream, a topical immune response modifier that stimulates the production of interferon alfa and other cytokines, is an effective topical treatment for Bowen's disease.

METHODS

This was a phase II, open-label study in 16 patients, treating a single biopsy-proven plaque of Bowen's disease that was 1 cm or larger in diameter, with once-daily self-application of imiquimod 5% cream for 16 weeks. A biopsy was performed on the treated area 6 weeks after the end of treatment, with patient follow-up at 3 and 6 months. Lymphocyte CD4/CD8 ratios were analyzed in pretreatment and posttreatment biopsy specimens by immunophenotyping the lymphocytic infiltrate.

RESULTS

Sixteen patients with Bowen's disease lesions ranging from 1 to 5.4 cm in diameter (0.7-21.6 cm(2) in area) were treated. Fifteen of these lesions were on the legs, and one was on the shoulder. Fourteen of the 15 patients (93% per protocol analysis) had no residual tumor present in their 6-week posttreatment biopsy specimens. One patient died of unrelated intercurrent illness before a biopsy specimen could be obtained. The median CD4/CD8 lymphocyte ratio in pretreatment biopsy specimens was 2:1, and this was reversed to a median of 1:2.2 in the posttreatment specimens. Ten patients completed 16 weeks of treatment, but 6 patients ceased treatment early (between 4 and 8 weeks) because of local skin reactions.

CONCLUSION

Imiquimod 5% cream appears to be an effective treatment for Bowen's disease on the lower limbs. The 93% positive treatment response in biopsy-proven cases (excludes patient who died from an intercurrent illness who did not undergo a posttreatment biopsy) compares favorably with other current treatment modalities. The dosing schedule and length of treatment for Bowen's disease require further evaluation.

Guidelines for management of Bowen's disease. British Association of Dermatologists

These guidelines for management of Bowen's disease have been prepared for dermatologists on behalf of the British Association of Dermatologists. They present evidence-based guidance for treatment, with identification of the strength of evidence available at the time of preparation of the guidelines, and a brief overview of epidemiological aspects, diagnosis and investigation.

Ultrasound-enhanced diffusion into coupling gel during phonophoresis of 5-fluorouracil

PURPOSE

To investigate the competitive transport across skin and back-diffusion of 5-fluorouracil into coupling gel under the influence of ultrasound, heat-alone and Azone enhancement.

METHODS

The ultrasound effect on 5-fluorouracil penetration through whole rat skin was investigated in modified diffusion cells using a commercial ultrasound generator which was calibrated with a bilaminar membrane hydrophone.

RESULTS

Ultrasonic dosimetry measurements demonstrated that the skin membrane was subjected to a complex and unpredictable standing wave field which induced physiologically acceptable heating of the tissue. Surprisingly, ultrasonication produced a decrease in percutaneous drug penetration. Quantification studies indicated that this effect was due to the diffusive loss of the hydrophilic substance 5-fluorouracil from the skin surface into the overlying volume of coupling gel. This phenomenon could be duplicated by the application of conductive heating, indicating that the thermal effects of ultrasound were probably responsible for accelerated 5-fluorouracil diffusion through the gel.

CONCLUSION

This study acutely demonstrates how formulation design of the donor vehicle/coupling gel may radically affect therapeutic efficacy in phonophoretic systems.

Treatment of cutaneous Bowen's disease with particular emphasis on the problem of lower leg lesions

Bowen's disease has a particular predilection for the lower leg, especially in women. A review of the literature for treating Bowen's disease is presented and the problems associated with treating the lower leg emphasized. Evidence for the various treatment modalities used to treat Bowen's disease largely comes from studies that lack good methodology in terms of standardized techniques, patient controls and adequate follow-up. In particular the widely accepted recommendation for excision is not supported by evidence that this treatment is superior to other modalities. The choice of treatment for Bowen's disease should take into account the patient's general condition, the site and size of the lesion.