New treatment modalities for basal cell carcinoma

High-Risk Recurrence Basal Cell Carcinoma: Focus on Hedgehog Pathway Inhibitors and Review of the Literature

Basal cell carcinoma is the most common skin tumour, with the majority of the cases occurring on the head and neck district, where cosmetic and functional results are crucial. It can be locally destructive if not diagnosed early and treated appropriately. Surgery is the treatment of choice for most lesions, but aggressive, recurrent, or unresectable tumours can be challenging to manage. Advanced basal cell carcinoma includes high recurrence risk subtypes, in which standard therapies demonstrate lack of efficacy. This led to a need for investigating more deeply the pathogenesis of the disease and to the discovery of the implication of the hedgehog pathway. The development of systemic inhibitors of this pathway provides new treatment options for patients with advanced disease, resulting in survival improvement. Food and Drug Administration, before, and European Medicines Agency later approved 2 Hedgehog pathway inhibitors for the treatment of advanced basal cell carcinomas, vismodegib and sonidegib. Here, we present a review of the current English language literature trying to analyze differences in the 2 drugs as a head-to-head comparison between them has not already been documented in a randomized controlled clinical trial. Although vismodegib and sonidegib showed similar efficacy and safety profiles, in an indirect comparison scenario, sonidegib has shown slightly better outcomes in locally advanced basal cell carcinoma than vismodegib. They present different molecular structures, as they bind different residues on their targets and develop resistance for different mutations. In a future scenario, clinical trials comparing the 2 drugs are needed, as well as expanding data on discontinuation of therapy and/or consequential administration of them, with the aim to improve our clinical practise.

Photoactivated cytotoxicity of ferrocenyl-terpyridine oxovanadium(IV) complexes of curcuminoids

Oxovanadium(IV) complexes, viz. [VO(Fc-tpy)(Curc)](ClO4) (1), [VO(Fc-tpy)(bDHC)](ClO4) (2), [VO(Fc-tpy)(bDMC)](ClO4) (3) and [VO(Ph-tpy)(Curc)](ClO4) (4), of 4'-ferrocenyl-2,2':6',2″-terpyridine (Fc-tpy) and 4'-phenyl-2,2':6',2″-terpyridine (Ph-tpy) and monoanionic curcumin (Curc), bis-dehydroxycurcmin (bDHC) and bis-demethoxycurcumin (bDMC) were prepared, characterized and their photo-induced DNA cleavage activity and photocytotoxicity in visible light studied. The ferrocenyl complexes 1-3 showed an intense metal-to-ligand charge transfer band near 585 nm in DMF and displayed Fc(+)/Fc and V(IV)/V(III) redox couples near 0.65 V and -1.05 V vs. SCE in DMF-0.1 M TBAP. The complexes as avid binders to calf thymus DNA showed significant photocleavage of plasmid DNA in red light of 647 nm forming OH radicals. The complexes showed photocytotoxicity in HeLa and Hep G2 cancer cells in visible light of 400-700 nm with low dark toxicity. ICP-MS and fluorescence microscopic studies exhibited significant cellular uptake of the complexes within 4 h of treatment with complexes. The treatment with complex 1 resulted in the formation of reactive oxygen species inside the HeLa cells which was evidenced from the DCFDA assay.

New and emerging vaccination strategies for prevention and treatment of dermatological diseases

Accelerated by the rapid advancements of our understanding of the molecular and cellular pathology of diseases and of the components and mechanisms of cellular and humoral immune responses, new vaccination strategies are being developed and explored for treatment and prevention of infectious diseases, cancer, autoimmune disorders and allergies. Many newly developed vaccination strategies are already in clinical trials, some with very promising results. Although most of these strategies are still at very early stages of their development, it is foreseeable that vaccination will evolve to play an important role in prevention, treatment and management of all the above classes of diseases.

Ultrasound enhances the efficacy of chlorin E6-mediated photodynamic therapy in MDA-MB-231 cells

Sono-photodynamic therapy (SPDT) is a new modality for cancer treatment. Some studies have reported enhanced tumor cytotoxicity when sonodynamic therapy (SDT) is combined with photodynamic therapy (PDT). In this study, we investigated the cytotoxic effect of SPDT-activated chlorin e6 (Ce6) on MDA-MB-231 cells. Ce6 was found to localize mainly in mitochondria, with maximal uptake within 4 h. Cell survival was estimated by MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltertrazolium bromide tetrazolium) assay 24 h after irradiation; the combined therapy enhanced cytotoxicity to a greater extent. Apoptosis was analyzed using annexin V-PE/7-ADD (7-aminoactinomycin D) staining as well as DAPI (4', 6-diamidino-2-phenylindole) staining, and the results indicated that the cells with apoptotic characteristics were significantly increased in groups given combined therapy. Rhodamine-123 staining and cytochrome c release revealed more serious damage of mitochondria after combined treatment. The generation of reactive oxygen species detected by flow cytometry was greatly increased in cells treated with the combination therapy, and the loss in cell viability could be effectively rescued with the reactive oxygen species inhibitor N-acetylcysteine. Moreover, enhancement of cell membrane permeability after ultrasound treatment was evaluated using FD-500, and it was found that the much higher uptake of Ce6 might be involved in PDT therapy with pre-treatment ultrasound. These results suggest that ultrasound enhances the cytotoxicity of Ce6-mediated PDT, possibly because of the increased intracellular Ce6 level and ROS formation by ultrasound pre-treatment.

Current treatment patterns in non-melanoma skin cancer across Europe

With marked increases in the annual incidence of non-melanoma skin cancer (NMSC) across the globe, its management is of increasing concern to dermatologists. This paper summarises the epidemiology and risk factors and provides an overview of treatment approaches in NMSC across Europe, including surgery, topical 5-fluorouracil and cryotherapy, in the context of the trade-offs that exist in finding optimal treatment outcomes. The paper will also briefly examine new approaches such as immunomodulators and the growing body of data on photodynamic therapy (PDT) using methyl aminolevulinate (MAL), including the authors' personal experience of the efficacy and cosmetic results obtained with these newer therapies.

Bioavailability of aminolaevulinic acid and methylaminolaevulinate in basal cell carcinomas: a perfusion study using microdialysis in vivo

BACKGROUND

Photodynamic therapy is becoming a popular treatment for superficial nonmelanoma precancerous and cancerous lesions, showing excellent cosmetic results. Nevertheless, the reported cure rates vary and the transdermal penetration of drugs has been discussed as a limiting factor, particularly for treatment of nodular basal cell carcinoma (BCC).

OBJECTIVES

To investigate the transdermal penetration of aminolaevulinic acid (ALA) and methylaminolaevulinate (MAL) in BCC in vivo using a microdialysis technique. The different prodrugs were compared and the effect of curettage was studied.

METHODS

Twenty patients with 27 histologically verified BCCs (13 superficial, 14 nodular) were included. All lesions were located at the front of the body (head and face excluded). The first 10 patients included were treated with MAL (13 BCCs), and the following 10 patients with ALA (14 BCCs). A light curettage was performed on every second lesion (curettage, n = 13; noncurettage, n = 14). Microdialysis catheters were inserted into the tumours at tissue depths varying from 0.4 to 1.9 mm. Dialysates were collected at 15-30-min intervals for 4 h and the interstitial concentrations of MAL and ALA were determined using high-performance liquid chromatography.

RESULTS

No significant difference in interstitial drug concentration was observed between lesions treated with ALA or MAL during the 4-h measurement period. However, for the lesions with deeper catheter locations, i.e. at or below 1 mm (n = 11), drug concentrations above the detection limit were obtained in only six lesions. All but one BCC with superficial catheter location, i.e. < 1 mm (n = 16), exhibited detectable drug concentration (P = 0.026). The interstitial peak concentrations were reached within 90 min in 23 of the 27 BCCs, but were not found to be correlated with the depth of the catheters. No difference was found when comparing superficial and nodular BCCs, and the effect of curettage was found to be negligible.

CONCLUSIONS

The results imply that there is no significant difference in transdermal penetration of ALA and MAL in tumour tissue. Detectable levels of drug were not obtained in almost 50% of the lesions where catheters were situated 1-1.9 mm in the lesion. Curettage was not found to affect the interstitial concentration, indicating that penetration of drug indeed might be a problem when treating BCCs thicker than 1 mm.

Histological and immunohistochemical evaluation of basal cell carcinoma following curettage and electrodessication

BACKGROUND

Basal cell carcinoma (BCC) is the most frequent non-melanoma skin cancer. Curettage and electrosurgery is probably the method most commonly used by dermatologists for the treatment of small and low risk BCCs. However, one is unable to determine the persistence of any residual tumor. This study was carried out in order to demonstrate the presence of such tumoral cells after curettage and electrofulguration.

METHODS

20 primary BCC outpatients were studied at the Dermatology Service of Getúlio Vargas Hospital in the city of Teresina--State of Piauí--Brazil, with lesions of up to 1 cm in diameter on the face, and up to 1.5 cm elsewhere, and with no clinical signs of sclerosing and micronodular forms. Patients were anesthetized with 2% lidocaine with vasoconstrion and the lesions were curetted. Electrofulguration was conducted throughout the curetted area and 1 millimeter beyond. After two curettage and electrofulguration cycles, an incision around the resultant ulcer was made 2 mm beyond the visible bloody borders and in the base to the middle of subcutaneous fat. Two straight incisions were also carried out intersecting the lesion center, dividing it into quadrants. Each quadrant was incised and then fixed with 10% formalin. The quadrants and the fragments resulting from the curettage were in paraffin and histopathologically tested through hematoxylin/eosin stains and immunohistochemistry with Ber-EP4 marker.

RESULTS

There was evidence of persistent BCC in 5 of the 20 sites treated (25%): four (20%) in one quadrant and one (5%) in all four quadrants. 70-100% of tumor cells expressed Ber-EP4 in all 20 BCCs.

CONCLUSIONS

The persistence of tumoral residues after 2 curettage and electrofulguration cycles for basal cell carcinoma was found in 5 sites treated (25%). Despite the small cohort, such findings are very similar to those of other studies that applied curettage and electrocoagulation and indicated the probability of 25% of tumoral persistence.

Intracellular chemiluminescence activates targeted photodynamic destruction of leukaemic cells

Photodynamic therapy (PDT) involves a two-stage process. A light-absorbing photosensitiser (Ps) is endocytosed and then stimulated by light, inducing transfer of energy to a cytoplasmic acceptor molecule and the generation of reactive oxygen species that initiate damage to cellular membrane components and cytolysis. The expanded use of PDT in the clinic is hindered by the lack of Ps target-cell specificity and the limited tissue penetration by external light radiation. This study demonstrates that bioconjugates composed of transferrin and haematoporphyrin (Tf–Hp), significantly improve the specificity and efficiency of PDT for erythroleukemic cells by a factor of almost seven-fold. Fluorescence microscopy showed that the conjugates accumulate in intracellular vesicles whereas free Hp was mostly membrane bound. Experiments with cells deliberately exposed to Tf–Hp at <LD₁₀₀ doses showed that surviving cells did not develop resistance to subsequent treatments with the conjugate. Furthermore, we show that the compound luminol induces intracellular chemiluminescence. This strategy was then used to obviate the use of external radiation for Ps activation by incubating the cells with luminol either before or together with Tf–Hp. This novel chemical means of PDT activation induced cytotoxicity in 95% of cells. These combined approaches provide an opportunity to develop broader and more effective applications of PDT.

A clinical review of PDT for cutaneous malignancies

More critical than for most other anatomy, intervention to cutaneous malignancy must not only be therapeutically successful but also achieve excellent cosmetic and functional outcome. As it can achieve those ends, PDT has moved to the forefront in the management of skin cancer. A number of well designed clinical trials and large patient series have reported outstanding outcomes for many histologies. This paper will review the rationale and outcomes of cutaneous PDT to malignancy using both topical and systemic photosensitizers. The benefits and drawbacks of cutaneous PDT are also examined.

Aggressive and neglected basal cell carcinoma

BACKGROUND

Basal cell carcinoma (BCC) is the most common cutaneous malignancy and usually has a benign coarse. Rarely, examples of aggressive and neglected types of this tumor are seen.

OBJECTIVE

To present an interesting and dramatic example of how some people neglect their tumors and how devastating the sequelae can be.

METHODS

We report a 58-year-old man with an extensive BCC and signs of cranial nerve involvement.

RESULTS

The patient had a large, infected ulcer on his scalp. He also had skull bone destruction, osteomyelitis, mastoiditis, cranial nerve paralysis, and radiographic features of the skull base and upper cervical soft tissue involvement. Pathologic studies revealed an infiltrating form of BCC.

CONCLUSIONS

If left untreated and neglected, as in this case, BCC can become inoperable and complicated.

Imiquimod treatment of superficial and nodular basal cell carcinoma: 12-week open-label trial

BACKGROUND

Imiquimod is an immune response modifier shown to be effective in basal cell carcinoma (BCC).

OBJECTIVE

To evaluate the efficacy, tolerability, and response durability of imiquimod 5% cream in selected patients with superficial and/or nodular BCCs.

METHODS

Seventy-five superficial and 19 nodular BCCs in 49 patients were treated with imiquimod once daily three times a week for up to 12 weeks.

RESULTS

Of the 49 enrolled patients, 1 discontinued the study and 1 was lost to follow-up. After 12 weeks of treatment, a complete response occurred in 70 of 75 (93.3%) superficial BCCs and a partial response in 4 of 75 (5.3%) superficial BCCs. Ten of 19 (52.6%) nodular BCCs cleared after 12 weeks, whereas 7 (36.8%) showed partial remission. Adverse side effects were limited to local skin reactions. Recurrence was observed in 2 of 70 (2.9%) successfully treated superficial BCCs 6 and 8 months after treatment discontinuation. No recurrence was detected in 68 of 70 (97.1%) superficial BCCs and in 10 successfully treated nodular BCCs after 12 to 34 months of follow-up (mean 23 months).

CONCLUSIONS

In our patient population, treatment of superficial BCCs with topical imiquimod for 12 weeks produced an excellent clinical response overall, with complete remission maintained after a mean of 23 months.

Melanocortin ligands: 30 years of structure-activity relationship (SAR) studies

The challenge of peptide and peptidomimetic research is the development of methods and techniques to improve the biological properties of native peptides and to convert peptide ligands into non-peptide compounds. Improved biological properties of peptides includes enhancement of stability, potency, and receptor selectivity, for both in vivo and in vitro applications. The design of a ligand with specific activity and desired biological properties is a complex task, and, to accomplish this objective, knowledge about putative interactions between a ligand and the corresponding receptor will be valuable. This includes interactions for both the binding and signal transduction processes. Structure-activity relationship (SAR) studies involve systematic modification of a lead peptide and are designed to provide insight into potential interactions involved in the formation of the ligand-receptor complex. It is desirable to have knowledge about both favorable and unfavorable processes that may occur in putative ligand-receptor interactions that result in either receptor stimulation or inhibition. Herein, we discuss various SAR studies that have involved melanocortin peptides over three decades and the information these studies have provided to the melanocortin field.

Topical treatment of basal cell carcinoma with tazarotene: a clinicopathological study on a large series of cases

BACKGROUND

Basal cell carcinoma (BCC) is the most common cancer in humans. Medical treatment modalities offer cost reductions and clinical advantages in selected cases such as low-risk areas, surgically inaccessible sites, patients with multiple neoplasms, and older, infirm or anticoagulated subjects. Tazarotene has been proposed for the treatment of BCC; however, data on its efficacy are lacking.

OBJECTIVES

To investigate the efficacy of tazarotene in a large series of BCCs, better to define the clinical advantages and the mechanisms of action in vivo.

METHODS

Tazarotene 0.1% gel was applied daily for 24 weeks to 154 small superficial and nodular BBCs. Clinicopathological changes were followed during the therapy by dermoscopic and histological examination. Proliferation, retinoic acid receptors and apoptosis were investigated by immunohistochemistry and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick-end labelling on biopsies.

RESULTS

At 24 weeks of therapy, 70.8% of the BCCs showed > 50% clinical and dermoscopic regression, and 30.5% healed without recurrences after 3 years of follow-up. At 12 weeks, biopsies showed that regression was associated with reduced proliferation and increased apoptosis of basaliomatous cells. Most unresponsive tumours displayed a keratotic differentiation.

CONCLUSIONS

Tazarotene was effective in the majority of superficial and nodular undifferentiated BCCs treated, possibly by antiproliferative and proapoptotic actions in vivo. Keratotic BCCs were the major type among the unresponsive tumours, and were characterized by overexpression of p53 and cellular retinol binding protein-1 in comparison with undifferentiated tumours. Topical tazarotene represents an alternative medical choice for selected cases of BCC.

Topical photodynamic therapy in clinical dermatology

The growing incidence of cutaneous malignancies each year necessitates the development of new and more effective methods for both the diagnosis and the treatment of cancerous lesions, while assuring better cosmetic results and improving patient satisfaction. With that in mind, the use of topical photodynamic therapy (PDT) has been explored in the treatment as well as the diagnosis of various cutaneous malignancies. Using the intrinsic cellular haem biosynthetic pathway and principles of photoillumination, topical PDT carries the goal of selectively targeting abnormal cells, while preserving the normal surrounding structures. This paper will discuss the various applications and data on the use of topical PDT in dermatology.

Superficial radiotherapy for patients with basal cell carcinoma: recurrence rates, histologic subtypes, and expression of p53 and Bcl-2

BACKGROUND

The histologic subtype of a basal cell carcinoma (BCC) may be an important factor for the success of a certain treatment modality. In the current article, the authors report recurrence rates among patients with BCC after superficial radiotherapy as well as Bcl-2 and p53 expression levels stratified by BCC subtype.

METHODS

The authors performed a retrospective study of 175 BCCs in 148 patients (64 female patients and 84 male patients; mean age, 69 years) who were treated with radiotherapy. According to their histologic patterns, BCCs were classified as nodular (n = 103), superficial (n = 25), and sclerosing (n = 47). In addition, six patients with metatypic BCC were reviewed. Bcl-2 and p53 protein expression was examined on a tissue microarray of 60 BCC samples (18 nodular tumors, 12 superficial tumors, and 30 sclerosing tumors).

RESULTS

The estimated 5-year recurrence rate for all patients with BCC was 15.8%: 8.2% for patients with the nodular subtype, 26.1% for patients with the superficial subtype, and 27.7% for patients with the sclerosing subtype (Kaplan-Meier analysis: P = 0.055). The median follow-up was 48 months. The mean time to recurrence was 20 months, and 86.4% of all recurrences occurred within 3 years after treatment. No gender-specific differences were observed. In addition, one of six metatypic BCCs recurred. Nuclear p53 immunoreactivity and low Bcl-2 expression were significantly correlated with the sclerosing subtype. Overall, 61.5% of patients developed additional neoplasms during follow-up (76 developed additional BCCs, 15 developed squamous cell carcinomas, and 6 developed Bowen disease).

CONCLUSIONS

The sclerosing subtype of BCC was a risk factor for recurrence after radiotherapy. In contrast, excellent results were achieved for patients with predominant nodular subtype. Nevertheless, radiotherapy may be the therapy of choice for patients with all BCC subtypes, depending on the individual patient's characteristics. Expression analyses confirmed that p53 and Bcl-2 levels may be used as indicators for the aggressiveness of a BCC subtype. Due to the high incidence of additional skin malignancies, patients with BCC need careful follow-up.

Environment, phenotype and genetics: risk factors associated with BCC of the skin

Basal cell carcinoma is the most common cancer in Caucasians and its incidence is rising. Whilst not life threatening, the tumor can cause substantial morbidity and because of long follow-up, it places a major burden on healthcare agencies worldwide. Patients with the disease demonstrate wide phenotypic diversity with respect to tumor numbers, rate of tumor appearance and site. The factors involved in patient susceptibility to basal cell carcinoma are not well understood although exposure to ultraviolet radiation in sunlight appears critical. In this review we discuss the role of environmental and genetic factors on predisposition to basal cell carcinoma and illustrate how stratification of the basal cell carcinoma cohort into high-risk subgroups is helpful in identifying factors significant in disease susceptibility.

The future of vaccination as a treatment strategy in dermatological diseases

Vaccination approaches are increasingly explored as means for both prevention and therapy of skin diseases. These development are boosted by the rapidly accumulating knowledge of the molecular and cellular bases of these disease and the antigens involved, on the one hand, and of the components and mechanisms of cellular and humoral immune responses, on the other. In a number of cases these newly developed vaccination strategies are already tested in clinical trials. Although most of them are still in very early stages of the development, it is foreseeable that vaccination will emerge as an important option for prevention and treatment of infectious skin diseases as well as of cancer, allergies and maybe, auto-immune disorders.