Immunotherapy of basal cell carcinoma: evolving approaches

Novel medical strategies combating nonmelanoma skin cancer

The incidence of nonmelanoma skin cancer (NMSC) continues to rise, partly because of aging, the frequency of early childhood sunburns, and sporadic extreme recreational sun exposure. A nonsurgical approach to selected cutaneous malignancy could possibly reduce the cost as well as morbidity of surgical treatment for NMSC. There has been growing interest in isolating compounds that could suppress or reverse the biochemical changes necessary for cutaneous malignancies to progress by pharmacologic intervention. By targeting diverse pathways recognized as important in the pathogenesis of nonmelanoma skin cancers, a combination approach with multiple agents or addition of chemopreventative agents to topical sunscreens may offer the potential for novel and synergistic therapies in treating nonmelanoma skin cancer. This preliminary information will expand to include more therapeutic options for NMSC in the future.

Immunotherapy in nonmelanoma skin cancer

Nonmelanoma skin cancer is the most common type of cancer in humans. The role of the immune system in the prevention and regression of cancer is significant. UV radiation, being the most important risk factor in the development of skin cancer, has a suppressive effect on local and systemic immune effectors. Different immunotherapeutic approaches have been used for the treatment of nonmelanoma skin cancer including adoptive T-cell therapies, vaccine-based strategies, cytokines and monoclonal antibodies. The most important advancement with promising effects in the field of nonmelanoma skin cancer immunotherapy is the topical immune response modifier imiquimod. In addition, immunoprevention has been successfully applied for autosomal dominant basal cell nevus syndrome. Immunotherapeutic approaches provide a new modality for the treatment of recurrent or multiple nonmelanoma skin tumors.

Basal cell carcinoma in a child

Basal cell carcinoma is the most commonly seen nonmelanoma skin cancer which is rarely encountered in the childhood period. An 11-year old child was admitted to our clinic due to an erythematous and a slightly pigmented lesion with a 3 × 4 cm diameter on his posterior scalp. Macroscopically, the lesion was excised with a 10 mm safety margin. Pathologic examination revealed a basal cell carcinoma. No symptoms or signs of a syndrome were observed both in the patient and his family.

Treatment of advanced, recurrent, resistant to previous treatments basal and squamous cell skin carcinomas with a synergistic formulation of interferons. Open, prospective study

BACKGROUND

Aggressive non-melanoma skin cancer (deeply infiltrating, recurrent, and morphea form lesions) are therapeutically challenging because they require considerable tissue loss and may demand radical disfiguring surgery. Interferons (IFN) may provide a non-surgical approach to the management of these tumors. The aim of this work was to evaluate the effect of a formulation containing IFNs-alpha and -gamma in synergistic proportions on patients with recurrent, advanced basal cell (BCC) or squamous cell skin carcinomas (SCSC).

METHODS

Patients with extensive, recurrent, resistant to other procedures BCC or SCSC received the IFN formulation peri- and intralesionally, three times per week for 3 weeks. They had been previously treated with surgery and/or radiotherapy or chemotherapy. Thirteen weeks after the end of treatment, the original lesion sites were examined for histological evidence of remaining tumor.

RESULTS

Sixteen elder (median 70 years-old) patients were included. They beared 12 BCC and 4 SCSC ranging from 1.5 to 12.5 cm in the longest dimension. At the end of treatment 47% CR (complete tumor elimination), 40% PR (>30% tumor reduction), and 13% stable disease were obtained. None of the patients relapsed during the treatment period. The median duration of the response was 38 months. Only one patient with complete response had relapsed until today. Principal adverse reactions were influenza-like symptoms well known to occur with interferon therapy, which were well tolerated.

CONCLUSION

The peri- and intralesional combination of IFNs-alpha and -gamma was safe and showed effect for the treatment of advanced, recurrent and resistant to previous treatments of BCC and SCSC in elder patients. This is the first report of such treatment in patients with advance non-melanoma skin cancer. The encouraging result justifies further confirmatory trials.

TRIAL REGISTRATION

Current Controlled Trials RPCEC00000052.

Treatment of cutaneous tumors with topical 5% imiquimod cream

INTRODUCTION

There are various approaches to the treatment of cutaneous tumors; one of them is treatment with imiquimod, a synthetic toll-like receptor agonist with a low molecular weight that offers a topical, noninvasive, and non-surgical therapeutic option. The main objective of our study was to provide data on 89 patients who used a 5% imiquimod cream for the treatment of cutaneous tumors at the Cutaneous Oncology Group of the Dermatology Department of Hospital das Clinicas from 2003 to 2008.

MATERIALS AND METHODS

Here, we present our experience in the treatment of 123 cutaneous tumors of various types, including basal cell carcinoma (BCC), squamous cell carcinoma (SCC), Bowen's disease, erythroplasia of Queyrat, Paget's disease, and trichoepithelioma, with 5% imiquimod cream from 2003 to 2008 in the Cutaneous Oncology Group of the Dermatology Department of Hospital das Clinicas. Patients were divided into two separate groups according to their diagnosis and comorbidities; these comorbidities included epidermodysplasia verruciformis, xeroderma pigmentosum, albinism, basal cell nevus syndrome, Brooke-Spiegler syndrome, HIV, chronic lymphocytic leukemia, B-cell lymphoma, and kidney transplantation. Treatment duration, response to imiquimod, follow-up, recurrence, and local and systemic reactions associated with use of the drug were analyzed. Epidemiological data were obtained and cure rates were calculated.

RESULTS

The ratio of women to men was 1.28:1, and the mean age was 63.1 years. Tumors were located mainly on the face, back, trunk, and legs. For patients with comorbidities, the overall cure rate was 38%. These specific patients demonstrated cure rates of 83.5% for superficial BCC and 50% for Bowen's disease. Aggressive BCC and superficial and nodular BCC did not present a good response to treatment. Trichoepitheliomas and nodular BCC showed a partial response, and erythroplasia of Queyrat showed a complete response. For patients without comorbidities, the overall cure rate was 73%. For these patients, the cure rates were 85.7% for superficial and nodular BCC, 88% for superficial BCC, 57% for Bowen's disease, 50% for nodular BCC, and 50% for aggressive BCC. One SCC lesion demonstrated a complete response, and tumors caused by Paget's disease and erythroplasia of Queyrat presented a partial response. None of the tumors considered as clinically cured recurred. Thirty-seven lesions demonstrated no response to imiquimod. Having a cutaneous comorbidity, high-risk tumors such as mixed aggressive BCC (sclerodermiform or micronodular), nodular BCC, or Bowen's disease, and presenting no local reaction to imiquimod were considered as risk factors for a worse prognosis. We demonstrate that patients with no response to imiquimod, even when they demonstrated no local reaction, can undergo another cycle of six weeks of imiquimod treatment and show a complete response. The healing pattern led to good cosmetic outcomes, and the side effects were tolerable.

CONCLUSIONS

Our experience confirms imiquimod as an effective treatment option for several types of cutaneous tumors, especially in patients without the cutaneous comorbidities cited above and with low-risk tumors. Imiquimod has a relatively low cost compared to other therapeutic options and can be delivered via ambulatory care to patients with surgery contraindications, and its side effects are tolerable.

Toll-like receptors: applications to dermatologic disease

Toll-like receptors are a recently identified group of receptors that are an important component of the immune system. Thus far, ten different receptors have been identified and have unique tissue distribution, ligand binding properties, cellular signaling pathways, and cytokine production profiles. Importantly, ligand binding has been shown to regulate both the adaptive and host immune response; thus, defects in this pathway have the potential to lead to increased susceptibility to infection and inflammatory dysregulation. In this article, the burgeoning literature pertinent to the discovery and signaling mechanisms are reviewed in addition to the discussion of the important role Toll-like receptors may play in the pathogenesis of numerous skin diseases.

LEARNING OBJECTIVE

At the completion of this learning activity, participants should be familiar with the role of Toll-like receptors in host defenses and their relevance to dermatologic diseases.

Topical Immunotherapy: What's New

Further understanding of the pathogenesis of dermatologic conditions at a molecular level has led to targeted therapies. The topical immune response modifiers have contributed significantly to the treatment of cutaneous diseases. New topical remedies, particularly the Toll-like receptor agonists and calcineurin inhibitors, have added to the clinical armamentarium and have further advanced clinicians' ability to treat a wide variety of benign, premalignant, and malignant conditions. Furthermore, these agents have contributed to the understanding of the disease process. The next decade will witness even greater advances in targeted immunotherapies for dermatologic disease.

Imiquimod for the treatment of skin cancer

Imiquimod is a topically applied immunomodulator. Although initially approved for genital and perianal warts, dermatologists have prescribed this compound for many neoplastic and nonneoplastic skin conditions. The US Food and Drug Administration recently approved imiquimod for the treatment of actinic keratoses. This article reviews the literature on imiquimod in the treatment of cutaneous malignancies.

UV Dose Determines Key Characteristics of Nonmelanoma Skin Cancer

Basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), known as nonmelanoma skin cancer (NMSC), are the most common cancers worldwide. Although many factors are involved in the pathogenesis of NMSC, UV radiation is an important risk factor. A fundamental question in skin cancer research is whether varying doses of total UV radiation influence key characteristics of NMSC. The hypothesis that differences in UV doses influence the BCC/SCC ratio, number of tumors, and anatomic location of the tumor was investigated in 311 participants having 326 tumors and with exposure to a broad range of UV doses. An epidemiologic questionnaire was given to each participant soliciting detailed information on exposure to solar radiation. Environmental UVA and UVB doses were measured continually for 6 years at a permanent UV monitoring station. The total ratio of BCC/SCC was 3.5. Participants who received low and high UV doses had a BCC/SCC ratio of 4.2. Those who received very high UV doses had a ratio of 2.1. A very high UV dose was also associated with the doubling of the total number of tumors per person and a significantly increased risk of having SCC, a more aggressive malignancy. Tumors in sun-exposed areas (on the body) were more common in participants who received high and very high UV doses. The tumors in sun-protected areas were associated with exposure to lower levels of UV. This large-scale population study provides evidence that varying doses of UV radiation have a profound influence on key characteristics of NMSC.