Intermittent topical 5-fluorouracil is effective without significant irritation in the treatment of actinic keratoses but prolongs treatment duration

Randomized clinical trial testing the efficacy and safety of 0.5% colchicine cream versus photodynamic therapy with methyl aminolevulinate in the treatment of skin field cancerization: study protocol

Background

The primary clinical manifestation of skin field cancerization is the presence of actinic keratoses (AKs). Current treatments for AKs related to skin field cancerization include photodynamic therapy (PDT) and colchicine. The objective of this study is to evaluate the efficacy and safety of 0.5% colchicine cream versus PDT with methyl aminolevulinate (MAL-PDT) in the treatment of skin field cancerization.

Methods

In a randomized controlled and open clinical trial with a blind histopathological and immunohistochemical analysis, 36 patients with up to 10 AKs on their forearms will be included from the outpatient clinic. The forearms will be randomized into two groups, clinically evaluated and biopsied for histopathology and immunohistochemistry (p53 and Ki67). One forearm will be treated with 0.5% colchicine cream for 10 days, and the other forearm will receive one session of MAL-PDT; the forearms will subsequently be reassessed clinically and histologically after 60 days (T60) of treatment. The primary endpoint will be the point of complete clearance of AKs in T60. The sample size will enable a detection in the reduction of over 10% in AK counts between the groups with power of 0.9 and an alpha of 0.05, accounting for an estimated dropout rate of 10%, resulting in 36 patients (72 forearms). All participants included in the randomized study will be part of the analysis, and the final outcomes of any dropouts will be the value of their last visit (LOCF). The statistical analysis will be performed using SPSS 22.0, and a p value < 5% will be considered to be significant.

Discussion

It is expected that colchicine will be superior to MAL-PDT in reducing AKs and in the skin field cancerization, and there will be good tolerability in both groups. Colchicine intervention is novel in that it provides a new alternative to MAL-PDT. Moreover, this drug is inexpensive that may be a potential treatment of skin field cancerization that can be prescribed in public health systems with good results.

Trial registration

The trial is registered in Brazilian Registry for Clinical Trials (Registration number: RBR-8y3sj9, date assigned May 4, 2016, retrospectively registered).

Understanding efficacy end-points in studies of field-directed therapy for actinic keratosis

BACKGROUND

The rates of short-term clearance of actinic keratoses appear to be comparable in clinical trials of topical treatments used in field therapy, but direct comparisons of efficacy results can be problematic. Trials use different efficacy end points, have different study designs, involve different anatomic sites, and enroll different patient populations. In addition, because adherence in real-world clinical practice differs from that observed in clinical trials, conclusions drawn from efficacy outcomes can be misleading. The objective of this review was to examine the efficacy end points used in studies of topical therapy for actinic keratosis, address other factors influencing efficacy outcomes in these studies, and discuss the possible influence of nonadherence on effectiveness.

METHODS

Review of the available literature on topical therapy for actinic keratosis.

RESULTS

The end points used to determine efficacy of therapies for actinic keratosis include a disparate group of outcomes, which can often make comparison between studies impossible.

CONCLUSIONS

Efficacy end points of clinical studies designed to assess the treatment of actinic keratosis should be standardized to facilitate between-trial comparisons, and studies should focus on the end points that are most clinically relevant.

Actinic keratosis: rationale and management

Actinic keratoses (AKs) are common skin lesions heralding an increased risk of developing squamous cell carcinoma (SCC) and other skin malignancies, arising principally due to excessive ultraviolet (UV) exposure. They are predominantly found in fair-skinned individuals, and increasingly, are a problem of the immunosuppressed. AKs may regress spontaneously, remain stable or transform to invasive SCC. The risk of SCC increases for those with more than 5 AKs, and the majority of SCCs arise from AKs. The main mechanisms of AK formation are inflammation, oxidative stress, immunosuppression, impaired apoptosis, mutagenesis, dysregulation of cell growth and proliferation, and tissue remodeling. Human papilloma virus has also been implicated in the formation of some AKs. Understanding these mechanisms guides the rationale behind the current available treatments for AKs. One of the main principles underpinning the management of AKs is that of field cancerization. Wide areas of skin are exposed to increasing amounts of UV light and other environmental insults as we age. This is especially true for the head, neck and forearms. These insults do not target only the skin where individual lesions develop, but also large areas where crops of AKs may appear. The skin between lesions is exposed to the same insults and is likely to contain as-yet undetectable preclinical lesions or areas of dysplastic cells. The whole affected area is known as the ‘field’. Management is therefore divided into lesion-directed and field-directed therapies. Current therapies include lesion-directed cryotherapy and/or excision, and topical field-directed creams: 5-fluorouracil, imiquimod, diclofenac, photodynamic therapy and ingenol mebutate. Combining lesion- and field-directed therapies has yielded good results and several novel therapies are under investigation. Treatment is variable and tailored to the individual making a gold standard management algorithm difficult to design. This literature review article aims to describe the rationale behind the best available therapies for AKs in light of current understanding of pathophysiology and epidemiology. A PubMed and MEDLINE search of literature was performed between January 1, 2000 and September 18, 2013. Where appropriate, articles published prior to this have been referenced. This is not a systematic review or meta-analysis, but aims to highlight the most up to date understanding of AK disease and its management.

[Topical therapy of squamous cell carcinoma]

Many forms of topical chemo- and immunotherapy are employed to treat skin cancers. Topical treatment is particularly attractive for field cancerization involving multiple non-melanoma skin cancers. The dermatologist must identify such patients and lesions and provide the most suited therapy.

A randomized trial of topical 5% 5-fluorouracil (Efudix cream) in the treatment of actinic keratoses comparing daily with weekly treatment

BACKGROUND

Topical 5-fluorouracil (5-FU) cream is widely used in the treatment of actinic keratoses (AKs) but the optimum treatment regimen that provides efficacy while minimizing side-effects remains unclear.

OBJECTIVES

A randomized trial to compare the efficacy and side-effects of daily vs. weekly application of 5% 5-FU in the treatment of AKs of the scalp and face.

PATIENTS/METHODS

Twenty patients were recruited and randomized to two groups. Group 1 (13 patients) applied 5% 5-FU twice daily for 3 weeks, group 2 (seven patients) applied 5% 5-FU twice daily for 1 day per week for 12 weeks. Patients were reviewed at weeks 3, 12, 24 and 52. At each review a lesion count and lesion map were completed and patients were asked to score efficacy and inflammation.

RESULTS

At week 0 the median lesion count was the same in both groups, 17.5 lesions. At 12 weeks the median lesion count in group 1 had fallen to 0 where it remained for the duration of follow-up. In group 2 the median lesion count fell to 6 at 12 weeks, 5.5 at 24 weeks and was 3 at 52 weeks. The difference in the lesion count was significant at all time points after week 0: P < 0.05 at weeks 12 and 52, and P < 0.01 at week 24. The mean inflammation score was higher in patients clear of AKs at 12 weeks compared with those who had not cleared, 3.8 compared with 1.9. This difference was statistically significant (P < 0.05) suggesting that inflammation is necessary for efficacy.

CONCLUSIONS

We conclude that daily application of 5% 5-FU cream is more effective than weekly application at clearing AKs from the scalp and face. Our results also suggest that inflammation is likely to be required to achieve a therapeutic effect.