Basal Cell Carcinoma: an updated review of pathogenesis and treatment options

Unsealed188 Rhenium Resin Brachytherapy in Non-Surgical Candidates With Refractory Basal Cell Carcinoma: Clinical Outcomes

INTRODUCTION

High-dose brachytherapy using a non-sealed 188Rhenium resin (188Re) is a new treatment option for difficult-to-treat basal cell carcinoma (BCC) that ensures a radical oncological outcome minimizing side effects.

OBJECTIVES

The aim of this retrospective study was to evaluate the clinical efficacy of high-dose standardized brachytherapy using an unsealed 188Re in the management of difficult-to-treat BCCs and to evaluate the risk factors of relapses.

METHODS

Between October 2017 and December 2022, patients affected by difficult-to-treat BCC were selected.

INCLUSION CRITERIA

histologically proven cutaneous BCC; thickness invasion no deeper than 3 mm; lesion located in the scalp, face, ears, or fingers or other areas in which surgery would have been difficult to perform or to destroy with scarce cosmetic-functional result; contraindication or refusal of surgery. All patients performed follow-up visits with videodermoscopy every 4-6 months.

RESULTS

Sixty-four consecutive patients affected by 82 histologically proven high-risk BCCs, were enrolled: 60 were nodular, 9 sclerodermiform, and 13 superficial. Average follow-up was 24 months. Brachytherapy with 188Re resin achieved a complete response in 93% of "difficult-to-treat" BCCs, with relapses occurring on average 24 months after the initial treatment. No statistically significant difference in response to brachytherapy was found in the anatomical area treated, size of the tumor, or previously treated vs. naive BCCs. The sclerodermiform histotype had a 7-fold higher risk of recurrence than nodular histotype; recurrence occurred approximately 12 weeks earlier.

CONCLUSION

High-dose 188Re brachytherapy is a noninvasive, easy to perform, well-tolerated approach to treat difficult BCC when surgery or other therapy techniques are not feasible.

Clinical outcomes and adverse events of Hedgehog pathway inhibitors for advanced basal cell carcinoma patients: A systematic review and meta-analysis

Background

Basal cell carcinoma (BCC) is the most common form of skin cancer and poses treatment challenges in advanced stages. Treatment options include surgery, radiotherapy, and systemic therapies, but tumor location and prior interventions can limit these methods. Hedgehog pathway inhibitors (HPIs) are used for patients unsuitable for conventional treatments.

Objective

This meta-analysis evaluated the effectiveness and safety profile of HPIs in managing advanced BCC.

Methods

We conducted a comprehensive literature review across Embase, Scopus, PubMed, and the Cochrane Central Register of Controlled Trials databases from inception until March 2024. The focus was on the effectiveness and safety of HPIs, with or without adjunct surgery or radiotherapy. Pooled objective response rates (ORRs) and 95% confidence intervals (CIs) were calculated using inverse variance random-effects models.

Results

The analysis comprised 16 studies, including 14 retrospective cohort studies, one prospective cohort study, and one randomized controlled trial, with 1689 participants. The pooled ORR for HPIs was 73% (95% CI 63%-82%; I2 = 93%) across all stages of the disease. For locally advanced disease, the ORR was 63% (95% CI 49%-75%; I2 = 89%), while for metastatic disease, it was 25% (95% CI 14%-40%; I2 = 19%). No significant differences were found in the effectiveness of different HPIs. ORRs ranged from 25% to 89% for patients who underwent surgery or radiotherapy.

Conclusions

This meta-analysis indicates that HPIs are more beneficial in treating locally advanced BCC than metastatic disease. No statistically significant differences were found in the effectiveness among various HPIs.

Metabolic Atlas of Human Eyelid Infiltrative Basal Cell Carcinoma

Purpose

Eyelid infiltrative basal cell carcinoma (iBCC) is the most common malignant tumor affecting the ocular adnexa, but studies on metabolic changes within its microenvironment and heterogeneity at the tumor invasive area are limited. This study aims to analyze metabolic differences among iBCC cell types using single-cell and spatial metabolomics analysis and to examine metabolic environment at the tumor invasive area.

Methods

Single-cell transcriptomic data of human basal cell carcinoma (BCC) were clustered and visualized using Uniform Manifold Approximation and Projection. Metabolic reprogramming was analyzed with single-cell flux estimation analysis. Spatial metabolomics data were obtained with the Timstof Flex MALDI 2 system, and Bruker software was used for region selection.

Results

Eight cell types were identified within the iBCC microenvironment. Differences between inflammatory cancer-associated fibroblasts and myofibroblastic cancer-associated fibroblasts were analyzed. Metabolic flux analysis showed increased glycolysis, glutamine, heme, and glutathione fluxes in the iBCC microenvironment. Spatial metabolomics revealed high levels of taurine, deoxy-GMP, O-phosphoethanolamine, and pyrithione. Both tumor and invasive regions had significant upregulation of fatty acid pathways, with marked increases in oleic and arachidonic acids at the invasive area. Specific upregulation of UDP-glucuronic acid and high UDP-glucose 6-dehydrogenase (UGDH) expression in the tumor region suggest UXS1 as a potential therapeutic target for iBCC.

Conclusions

This study establishes a metabolic microenvironment atlas of iBCC, revealing significant metabolic differences and the dominance of lipid and lysosome metabolism. Potential metabolic markers and characteristic substances in the invasive area offer new insights for immunotherapy and the exploration of BCC's metabolic mechanisms.

Minimizing Surgical Margins in Basal Cell Carcinoma: A Single Institution's Experience with Excision and Reconstruction Methods

Background  Basal cell carcinoma (BCC) is the predominant nonmelanocytic skin cancer, with preservation of both function and aesthetics being essential during tumor removal. Existing surgical margin guidelines primarily target ill-defined BCCs prevalent in Western countries. Therefore, this study aims to demonstrate the efficacy of surgical removal, propose modified guidelines for wide excision tailored to Asian patients, and share experiences with various reconstruction methods. Methods  This study encompasses 418 patients (447 cases) who underwent BCC excision from March 2015 to June 2023 at our institution. Wide excision extended 2 mm beyond the tumor edge universally, with an additional 2 mm resected if tumor cells persisted in the frozen biopsy, followed by appropriate reconstruction. Patient demographics, tumor features, reconstruction methods, complications, and recurrence rates were analyzed. Results  Predominantly, reconstructions involved local flaps (244), skin grafts (102), and direct closure (72). Significant differences were noted in age, location, and tumor size among these groups. The rate of second resection increased from upper to lower facial subunits, peaking at 11.1% in the lower subunit, with a statistically significant difference ( p  = 0.024). Additional resection was required in 5.50% of cases, with a significantly higher incidence of ill-defined borders, pigmentation, and the infiltrative subtype compared with others. Complications were minor; recurrence occurred in only one case, 6 months postinitial nasal dorsum surgery. Conclusion  Surgical excision is highly effective, supported by various reconstruction options. We propose narrower guidelines for wide excision considering tumor characteristics and recurrence locations, resulting in smaller defects addressed with simpler reconstruction methods.

Assessing the Concordance of Clinical and Pathological Diagnoses in Basal Cell Carcinoma Among the Iranian Population: A Cross-Sectional Analysis of 229 Cases

BACKGROUND

Nonmelanoma skin cancer (NMSC) is the most prevalent malignancy globally, with basal cell carcinoma (BCC) being the most common type.

AIMS

This study aims to evaluate the concordance between clinical and pathological diagnoses of BCC, emphasizing the importance of early detection.

METHODS AND RESULTS

In this cross-sectional study, we conducted a retrospective review of clinical and pathological records for 229 patients diagnosed with BCC between 2020 and 2024. The analysis focused on gender, age, lesion location, and diagnostic accuracy. Among the 229 patients, 193 were men (84.3%), and 131 (57.2%) had recorded clinical diagnoses. The mean age of diagnosed patients was 67.72 years. Lesions were primarily located on the scalp (29.5%), face (26.4%), and nose (13.9%). Of the pathological evaluations, 184 cases (80.3%) confirmed BCC, while 45 cases had alternative diagnoses. Notably, 94.6% of clinically diagnosed patients were suspected to have BCC by their physicians. A significant portion of cases (42%) lacked prior clinical diagnoses, reflecting a potential gap in education among nondermatologists regarding BCC recognition.

CONCLUSION

The study found high concordance between clinical and pathological diagnoses of BCC, underscoring the need for improved clinical assessment skills among healthcare providers. Collaboration with dermatologists is essential for accurate diagnosis and improved patient outcomes. Enhanced training in recognizing BCC symptoms is recommended to address the identified gaps in clinical suspicion.

Immunotherapy in Basal Cell Carcinoma

Basal cell carcinoma (BCC) is the most frequent of all cancers, with an increasing incidence. The first line therapy is surgical excision, but topical therapies can be used in low-risk superficial BCCs, while the more advanced, unresectable, or metastatic BCCs benefit from systemic therapies with hedgehog inhibitors and immunotherapy. The purpose of this review is to highlight local and systemic immunotherapies and their efficacy in the management of BCCs. Local therapies can be considered in superficial and low-risk nodular BCCs, with imiquimod frequently used for its antitumor and immunoregulatory properties. Imiquimod alone demonstrated higher histological clearance rates, but patients treated with imiquimod experienced more adverse events than ones treated with other therapies. Imiquimod can be used as an adjuvant before Mohs micrographic surgery and can also be combined with other local therapies, like curettage, electrodesiccation, cryosurgery, and photodynamic therapy, with some treatment methods yielding results comparable with the surgery. Interferons and Interleukin-2 were evaluated in a small number of studies with different results. Systemic immunotherapies with programmed death-ligand 1 (PD-L1) inhibitors showed inconsistent results in patients with advanced BCCs, being effective in some patients that progressed on or were intolerant to hedgehog pathway inhibitors (HHI).

Cutaneous Basal Cell Carcinoma In Situ: A Review of the World Literature

Cutaneous basal cell carcinoma (BCC) in situ is a recently recognized subtype of the skin neoplasm in which the abnormal cells are confined to the epidermis. BCC in situ of the skin was previously referred to as a superficial BCC. A review of the world literature has revealed 10 cutaneous BCCs in situ that have been described in nine patients but likely reflect a more general phenomenon. The neoplasm typically presents as an asymptomatic red plaque on the abdomen, upper extremity, back, and chest. Pathologic changes frequently show confluent tumor cells along the epidermal basal layer or superficial aggregates of neoplastic cells that are contiguous with the epidermis and extend into the dermis. Genomic evaluation has been performed in neoplasms from one individual with cutaneous BCC in situ and metastatic BCC; like other variants of BCC, an aberration of the PTCH1 gene was observed. In contrast to his liver metastasis, the in situ carcinoma had a lower tumor mutational burden, lacked programmed death-ligand 1 (PD-L1) and programmed death-ligand 2 (PD-L2) amplification and had a distinct PTCH1 mutation, suggesting that the in situ BCC of his skin and the metastatic BCC of his liver were derived from different clones of cells.

Non-Surgical Therapeutic Strategies for Non-Melanoma Skin Cancers

OPINION STATEMENT

Non-melanoma skin cancer (NMSC) is a globally prevalent skin disease, with basal cell carcinoma and squamous cell carcinoma accounting for 99% of NMSC cases. While surgical excision is the most common approach, numerous non-surgical therapies have rapidly advanced in recent years. In cases of low-risk NMSC, alongside surgical excision, priority should be given to physical therapy and photodynamic therapy. Physical therapy modalities, exemplified by electrodessication and curettage, emerge as safe and efficacious alternatives. In juxtaposition, photodynamic therapy, albeit relatively more costly, assumes preference for patients exhibiting heightened cosmetic concerns owing to the scarring risks inherent to physical therapy and surgical excision. Notably, the combination of curettage and photodynamic therapy has exhibited remarkable efficacy in the treatment of nodular basal cell carcinoma. Additionally, for elderly patients who may be intolerant to stimulation, modified photodynamic therapy offers an almost painless option. When surgery is unavoidable, photodynamic therapy can be a valuable adjunct, allowing for a more conservative surgical approach, either before or after the procedure. Radiotherapy holds a prominent role in comprehensive treatment strategies, especially for patients ineligible for surgical intervention or those with lesions precluding further surgical measures. In cases of NMSC exhibiting perineural invasion or lymphovascular involvement, adjunctive radiotherapy is advised; however, potential adverse effects necessitate careful consideration. For advanced NMSC cases where surgery and physical therapy fall short, immunotherapy provide viable solutions. Systemic therapy employing Hedgehog pathway inhibitors can be considered for patients with distant metastatic basal cell carcinoma, despite its low incidence, or individuals with locally advanced lesions who are not surgical candidates, or those encountering recurrences after resection and radiotherapy. However, close monitoring of disease progression and adverse reactions is crucial. In this evolving landscape of NMSC treatment, personalized and multidisciplinary approaches are key, ensuring optimal outcomes while prioritizing patient safety and satisfaction.

An update on the current and emerging pharmacotherapies for basal cell carcinomas

INTRODUCTION

Despite surgical approach is still the mainstay for basal cell carcinoma (BCC) management, several issues may limit the use of this technique, leading to the need for new treatments to offer patients a personalized approach.

AREAS COVERED

A comprehensive review of the available and emerging pharmacologic strategies for BCC management, including mechanisms of action, and potential adverse effects, has been performed to provide with an up-to-date manuscript on the current treatment scenario of BCC. Globally, targeting the Sonic-Hedgehog pathway is one of the main mechanisms of action of currently investigated drugs. Other alternatives are based on the concept of an enhancement of the immune response such as immune checkpoint inhibitors, or intra-tumor treatments.

EXPERT OPINION

Although low-risk BCCs are often treated with destructive methods or topical treatments, surgery is the mainstay of treatment for the majority of BCCs. However, several factors may limit the use of surgery in BCC management. Recently, major knowledge on BCCs pathogenesis has led to the development of effective and selective drugs. In our opinion, soon many drugs will be licensed, allowing clinicians to offer patients with BCC the right treatment at the right moment. Certainly, further studies are needed.

Efficacy and safety of sonidegib for the management of basal cell carcinoma: a drug safety evaluation

INTRODUCTION

Surgery is the standard management for most of basal cell carcinomas (BBCs). In some cases, also radiotherapy may be a valuable weapon as well as ablative and topical treatments. However, all these approaches may be limited by some tumor features. In this scenario, locally advanced BCCs (laBCC) and metastatic BCC, also defined as 'difficult-to-treat' BCC, remain the real treatment challenge. New knowledge on BCC pathogenesis, particularly the Hedgehog (HH) pathway, led to the development of new selective therapies such as vismodegib and sonidegib. In particular, sonidegib is an orally administered small molecules, which inhibits the HH signaling pathway through the binding to SMO receptor, recently approved for the management of adult patients with laBCC who are not amenable to curative surgery or radiation therapy.

AREAS COVERED

The purpose of this review is to analyze and discuss the efficacy and safety of sonidegib for the management of BCC, to provide a broad perspective on the currently available data.

EXPERT OPINION

Sonidegib is a valuable weapon for the management of difficult-to-treat BCC. Current data showed promising results in terms of effectiveness and safety. However, more studies are needed to underline its role in BCC management, also considering the presence of vismodegib, and to investigate its use in a long-term period.

Non-invasive imaging techniques in presurgical margin assessment of basal cell carcinoma: Current evidence

BACKGROUND

The diagnosis of basal cell carcinoma (BCC) is based on clinical and dermoscopical features. In uncertain cases, innovative imaging techniques, such as reflectance confocal microscopy (RCM) and optical coherence tomography (OCT), have been used. The main limitation of these techniques is the inability to study deep margins. HFUS (high-frequency ultrasound) and the most recent UHFUS (ultra-high-frequency ultrasound) have been used in various applications in dermatology, but they are not yet routinely used in the diagnosis of BCC. A key point in clinical practice is to find an imaging technique that can help to reduce post-surgical recurrences with a careful presurgical assessment of the lesional margins. This technique should show high sensitivity, specificity, reproducibility and simplicity of execution. This concept is very important for the optimal management of patients who are often elderly and have many comorbidities. The aim of the paper is to analyse the characteristics of current imaging techniques and the studies in the literature on this topic.

MATERIALS AND METHODS

The authors independently searched the MEDLINE, PubMed, Embase, Scopus, ScienceDirect and Cochrane Library databases for studies looking for non-invasive imaging techniques for the presurgical margin assessment of BCC.

RESULTS

Preoperative study of the BCC subtype can help to obtain a complete excision with free margins. Different non-invasive imaging techniques have been studied for in vivo evaluation of tumour margins, comparing the histologic evaluation with a radical surgery. The possibility to study the lateral and deep margins would allow a reduction of recurrences and sparing of healthy tissue.

CONCLUSION

HFUS and UHFUS represent the most promising, non-invasive techniques for the pre-operative study of BCC facilitating the characterization of vascularization, deep lateral margins and high-risk subtypes, although they are limited by insufficient literature unlike RCM and OCT.