Prognostic Factors for Treatment Failure of Photodynamic Therapy and 5-Fluorouracil in Bowen's Disease.

INTRODUCTION: Little is known about prognostic factors that may influence the response to non-invasive treatments of patients with Bowen's disease. The aim of this study was to identify patient and lesion characteristics that are associated with a higher risk of treatment failure after 5-fluorouracil and photodynamic therapy in Bowen's disease. The hypothesis that the thickness of the Bowen's lesion and extension along the hair follicle is associated with the risk of treatment failure after noninvasive treatment was also explored. METHODS: Data were derived from a non-inferiority randomized trial in which 169 patients were treated with 5% 5-fluorouracil cream twice daily for 4 weeks or 2 sessions of methylaminolevulinate photodynamic therapy with 1-week interval. All patients had histologically confirmed Bowen's disease of 4-40 mm. The initial 3 mm biopsy specimens were re-examined to measure the maximum histological lesion thickness and extension along the hair follicle. To evaluate the association between potential risk factors for treatment failure at 1-year follow-up, univariate and multivariate logistic regression analyses were used to calculate odds ratios (ORs) with 95% confidence intervals and p values. RESULTS: Histological lesion thickness was not significantly associated with treatment failure (OR: 0.84, p = 0.806), nor was involvement of the hair follicle (OR: 1.12, p = 0.813). Lesion diameter was the only risk factor that was significantly associated with 1-year risk of treatment failure (OR = 1.08 per mm increase, p = 0.021). When using the median value of 10 mm as cut-off point, the risk of treatment failure was 23.4% for lesions >10 mm compared to 10.3% for lesions ≤10 mm (OR: 2.66, p = 0.028). CONCLUSIONS: Only clinical lesion diameter was identified as a prognostic factor for response to non-invasive therapy in Bowen's disease.

Skin cancers are the most frequent cancers in fair-skinned populations, but we can prevent them.

Cancers of the skin are the most commonly occurring cancers in humans. In fair-skinned populations, up to 95% of keratinocyte skin cancers and 70-95% of cutaneous melanomas are caused by ultraviolet radiation and are thus theoretically preventable. Currently, however, there is no comprehensive global advice on practical steps to be taken to reduce the toll of skin cancer. To address this gap, an expert working group comprising clinicians and researchers from Africa, America, Asia, Australia, and Europe, together with learned societies (European Association of Dermato-Oncology, Euromelanoma, Euroskin, European Union of Medical Specialists, and the Melanoma World Society) reviewed the extant evidence and issued the following evidence-based recommendations for photoprotection as a strategy to prevent skin cancer. Fair skinned people, especially children, should minimise their exposure to ultraviolet radiation, and are advised to use protective measures when the UV index is forecast to reach 3 or higher. Protective measures include a combination of seeking shade, physical protection (e.g. clothing, hat, sunglasses), and applying broad-spectrum, SPF 30 + sunscreens to uncovered skin. Intentional exposure to solar ultraviolet radiation for the purpose of sunbathing and tanning is considered an unhealthy behaviour and should be avoided. Similarly, use of solaria and other artificial sources of ultraviolet radiation to encourage tanning should be strongly discouraged, through regulation if necessary. Primary prevention of skin cancer has a positive return on investment. We encourage policymakers to communicate these messages to the general public and promote their wider implementation.

European consensus-based interdisciplinary guideline for diagnosis, treatment and prevention of actinic keratoses, epithelial UV-induced dysplasia and field cancerization on behalf of European Association of Dermato-Oncology, European Dermatology Forum, European Academy of Dermatology and Venereology and Union of Medical Specialists (Union Européenne des Médecins Spécialistes).

A collaboration of multidisciplinary experts from the European Association of Dermato-Oncology, the European Dermatology Forum, the European Academy of Dermatology and Venereology, and the European Union of Medical Specialists was formed to develop European recommendations on AK diagnosis and treatment, based on current literature and expert consensus. This guideline addresses the epidemiology, diagnostics, risk stratification and treatments in immunocompetent as well as immunosuppressed patients. Actinic keratoses (AK) are potential precursors of cutaneous squamous cell carcinoma (cSCC) and display typical histopathologic and immunohistochemical features of this malignancy in an early stage. They can develop into cSSC in situ and become invasive in a low percentage of cases. AK is the most frequent neoplasia in white populations, frequently occurring within a cancerous field induced by ultraviolet radiation. Since it cannot be predicted, which lesion will progress to cSCC and when treatment is usually recommended. The diagnosis of AK and field cancerization is made by clinical examination. Dermatoscopy, confocal microscopy, optical coherence tomography or line-field confocal-OCT can help in the differential diagnosis of AK and other skin neoplasms. A biopsy is indicated in clinically and/or dermatoscopically suspicious and/or treatment-refractory lesions. The choice of treatment depends on patients' and lesion characteristics. For single non-hyperkeratotic lesions, the treatment can be started upon patient's request with destructive treatments or topical treatments. For multiple lesions, field cancerization treatment is advised with topical treatments and photodynamic therapy. Preventive measures such as sun protection, self-examination and repeated field cancerization treatments of previously affected skin areas in high-risk patients are advised.

Surgical excision versus topical 5% 5-fluorouracil and photodynamic therapy in treatment of Bowen's disease: A multicenter randomized controlled trial.

BACKGROUND: Randomized controlled trials comparing the effectiveness of 5-fluorouracil cream, methylaminolevulinate photodynamic therapy (MAL-PDT) and surgical excision in patients with Bowen's disease are lacking. METHODS: In this multicenter noninferiority trial, patients with a histologically proven Bowen's disease of 4-40 mm were randomly assigned to excision with 5 mm margin, 5% 5-fluorouracil cream twice daily for 4 weeks, or 2 sessions of MAL-PDT with 1 week interval. The primary outcome was the proportion of patients with sustained clearance at 12 months after treatment. A noninferiority margin of 22% was used. RESULTS: Between May 2019 and January 2021, 250 patients were randomized. The proportion of patients with sustained clearance was 97.4% (75/77) after excision, 85.7% (66/77) after 5-fluorouracil, and 82.1% (64/78) after MAL-PDT. Absolute differences were -11.7% (95% CI -18.9 to -4.5; P = .0049) for 5-fluorouracil versus excision and -15.4% (95% CI -23.1 to -7.6; P = .00078) for MAL-PDT versus excision. Both noninvasive treatments significantly more often led to good or excellent cosmetic outcome. CONCLUSIONS: Based on our predefined noninferiority margin of 22%, 5-fluorourcail is noninferior to excision and associated with better cosmetic outcome. For MAL-PDT noninferiority to excision cannot be concluded. Therefore, 5-fluorouracil should be preferred over excision and MAL-PDT in treatment of Bowen's disease.

European consensus-based interdisciplinary guideline for invasive cutaneous squamous cell carcinoma: Part 2. Treatment-Update 2023.

In order to update recommendations on treatment, supportive care, education, and follow-up of patients with invasive cutaneous squamous cell carcinoma (cSCC), a multidisciplinary panel of experts from the European Association of Dermato-Oncology (EADO), the European Dermatology Forum (EDF), the European Society for Radiotherapy and Oncology (ESTRO), the European Union of Medical Specialists (UEMS), the European Academy of Dermatology and Venereology (EADV), and the European Organisation of Research and Treatment of Cancer (EORTC) was formed. Recommendations were based on an evidence-based literature review, guidelines, and expert consensus. Treatment recommendations are presented for common primary cSCC (low risk, high risk), locally advanced cSCC, regional metastatic cSCC (operable or inoperable), and distant metastatic cSCC. For common primary cSCC, the first-line treatment is surgical excision with postoperative margin assessment or micrographically controlled surgery. Achieving clear surgical margins is the most important treatment consideration for patients with cSCCs amenable to surgery. Regarding adjuvant radiotherapy for patients with high-risk localised cSCC with clear surgical margins, current evidence has not shown significant benefit for those with at least one high-risk factor. Radiotherapy should be considered as the primary treatment for non-surgical candidates/tumours. For cSCC with cytologically or histologically confirmed regional nodal metastasis, lymph node dissection is recommended. For patients with metastatic or locally advanced cSCC who are not candidates for curative surgery or radiotherapy, anti-PD-1 agents are the first-line systemic treatment, with cemiplimab being the first approved systemic agent for advanced cSCC by the Food and Drugs Administration/European Medicines Agency. Second-line systemic treatments for advanced cSCC, include epidermal growth factor receptor inhibitors (cetuximab) combined with chemotherapy or radiotherapy. Multidisciplinary board decisions are mandatory for all patients with advanced cSCC, considering the risks of toxicity, the age and frailty of patients, and co-morbidities, including immunosuppression. Patients should be engaged in informed, shared decision-making on management and be provided with the best supportive care to improve symptom management and quality of life. The frequency of follow-up visits and investigations for subsequent new cSCC depends on underlying risk characteristics.

European consensus-based interdisciplinary guideline for invasive cutaneous squamous cell carcinoma. Part 1: Diagnostics and prevention-Update 2023.

Invasive cutaneous squamous cell carcinoma (cSCC) is one of the most common cancers in white populations, accounting for 20% of all cutaneous malignancies. Overall, cSCC mostly has very good prognosis after treatment, with 5-year cure rates greater than 90%. Despite the overall favourable prognosis and the proportionally rare deaths, cSCC is associated with a high total number of deaths due to its high incidence. A collaboration of multidisciplinary experts from the European Association of Dermato-Oncology (EADO), the European Dermatology Forum (EDF), the European Society for Radiotherapy and Oncology (ESTRO), the European Union of Medical Specialists (UEMS), the European Academy of Dermatology and Venereology (EADV) and the European Organization of Research and Treatment of Cancer (EORTC), was formed to update recommendations on cSCC, based on current literature and expert consensus. Part 1 of the guidelines addresses the updates on classification, epidemiology, diagnosis, risk stratification, staging and prevention in immunocompetent as well as immunosuppressed patients.

Effectiveness of a patient decision aid for patients with superficial basal cell carcinoma: A pre- and post-implementation study.

OBJECTIVE: This study evaluates whether using a patient decision aid (PDA) for patients with superficial basal-cell carcinoma (sBCC) results in a decreased decisional conflict level and increased knowledge. METHODS: In a prospective multicentre study, patient groups were included before and after implementation of a PDA. Decisional conflict levels were compared directly after making the treatment decision, measured once as the mean score on the decisional conflict scale (DCS). Higher scores correspond with higher conflict levels (0-100). Secondary outcomes were knowledge on treatment options, recognizing a BCC, and risk factors for developing a BCC measured on an adapted version of a validated knowledge questionnaire for melanoma patients, and patient satisfaction with the PDA. RESULTS: Data was available for 103 patients in the control-group and 109 in the PDA-group. The mean DCS score in the control-group was 22.78 (SD 14.76) compared to 22.34 (SD 14.54) in the PDA-group; the decrease was non-significant (p = 0.828). The average percentage correct answers on the knowledge questionnaire increased from 76.5% in the control-group to 80.5% in the PDA-group (p = 0.044). According to the majority of patients in the PDA-group (73.7%) the PDA had added value. CONCLUSION: Using the PDA had no significant effect on decisional conflict levels, but increased overall knowledge on relevant issues concerning sBCC. PRACTICE IMPLICATIONS: The PDA can be used as an informational tool by patients with sBCC.

Rate and Characteristics of Incompletely Excised Cutaneous Squamous Cell Carcinoma: A Dermatological Daily Practice Multicenter Prospective Cohort Study.

BACKGROUND: Incomplete excision of squamous cell carcinoma (cSCC) is associated with an increased risk of recurrence, metastasis, and mortality. OBJECTIVE: To determine the rate and characteristics of incompletely excised cSCC in a dermatological daily practice setting. METHODS: Prospective study of all patients who gave informed consent, with a cSCC treated with standard excision (SE) at 1 of 6 Departments of Dermatology in the Netherlands between 2015 and 2017. Pathological reports were screened to detect all incompletely excised cSCCs. RESULTS: A total of 592 patients with 679 cSCCs were included, whereby most cases were low risk cSCC (89%). The rate of incompletely excised cSCC was 4% ( n = 26), and the majority were high-risk cSCCs of which 24 invaded the deep excision margin. CONCLUSION: This prospective study showed that in a dermatological setting, the risk of an incompletely excised cSCC is low (4%) for a cohort that was dominated by low-risk cSCCs. Most incompletely excised cSCCs were of high risk, and incompleteness was almost always at the deep margins. These results suggest that for high-risk cSCC, one should pay attention especially to the deep margin when performing SE, and/or microscopic surgery should be considered.

Optical coherence tomography versus punch biopsy for diagnosis of basal cell carcinoma: a multicentre, randomised, non-inferiority trial.

BACKGROUND: Punch biopsy is the gold standard for diagnosis and subtyping of basal cell carcinoma. The aim of this study was to assess whether use of optical coherence tomography (OCT), a non-invasive imaging tool, might avoid the need for biopsy. METHODS: In a multicentre, randomised, non-inferiority trial, patients (aged ≥18 years) with an indication for biopsy of a suspected basal cell carcinoma outside the H-zone (high-risk zone) of the face were randomly assigned (1:1) to receive either OCT or punch biopsy (regular care) via a web-based randomisation system. Patients were enrolled from three participating centres in the Netherlands: Maastricht University Medical Centre+, Catharina Hospital Eindhoven, and Zuyderland Medical Centre Heerlen. Stratification factors for randomisation were participating centre and the grade of clinical basal cell carcinoma suspicion (high vs low). The primary endpoint was the proportion of patients free from a recurrent or residual lesion (malignant or premalignant) 12 months after treatment. Modified intention-to-treat and per-protocol analyses were conducted, with a predefined non-inferiority margin of -10%. This trial is registered with ClinicalTrials.gov number, NCT03848078, and is complete. FINDINGS: Between Feb 25, 2019, and Sept 2, 2020, 598 patients were enrolled and randomly assigned to either the regular care group (n=299) or the OCT group (n=299). Data on the primary endpoint were available in 553 patients (n=268 in the regular care group, n=285 in the OCT group). After median follow-up of 12·7 months (IQR 11·2-14·1) in the OCT group and 12·6 months (10·8-14·3) in the regular care group, 253 (94%) of 268 patients in the OCT group and 266 (93%) of 285 patients in the regular care group were free from recurrent or residual lesions (malignant or pre-malignant) 12 months after treatment. According to our modified intention-to-treat analysis, the absolute difference (OCT vs regular care) was 1·07% (95% CI -2·93 to 5·06; one-sided p=0·30), with the lower limit of the 95% CI not exceeding the predefined non-inferiority margin of -10%. Per-protocol analyses led to proportions free from a residual or recurrent lesion (premalignant or malignant) of 95% (250 of 263) in the OCT group and 94% (262 of 278) in the regular care group, and an absolute difference of 0·81% (95% CI -2·98 to 4·60; one-sided p=0·34). INTERPRETATION: OCT-guided diagnosis and treatment of basal cell carcinoma is non-inferior to regular care punch biopsy. Implementation of OCT for diagnosis of basal cell carcinoma could reduce the number of consultations and invasive procedures. FUNDING: The Netherlands Organization for Health Research and Development and Maurits en Anna de Kock Stichting.

Diagnosis and treatment of Merkel cell carcinoma: European consensus-based interdisciplinary guideline - Update 2022.

Merkel cell carcinoma (MCC) is a rare skin cancer, accounting for less than 1% of all cutaneous malignancies. It is found predominantly in white populations and risk factors include advanced age, ultraviolet exposure, male sex, immunosuppression, such as AIDS/HIV infection, haematological malignancies or solid organ transplantation, and Merkel cell polyomavirus infection. MCC is an aggressive tumour with 26% of cases presenting lymph node involvement at diagnosis and 8% with distant metastases. Five-year overall survival rates range between 48% and 63%. Two subsets of MCC have been characterised with distinct molecular pathogenetic pathways: ultraviolet-induced MCC versus virus-positive MCC, which carries a better prognosis. In both subtypes, there are alterations in the retinoblastoma protein and p53 gene structure and function. MCC typically manifests as a red nodule or plaque with fast growth, most commonly on sun exposed areas. Histopathology (small-cell neuroendocrine appearance) and immunohistochemistry (CK20 positivity and TTF-1 negativity) confirm the diagnosis. The current staging systems are the American Joint Committee on Cancer/Union for international Cancer control 8th edition. Baseline whole body imaging is encouraged to rule out regional and distant metastasis. For localised MCC, first-line treatment is surgical excision with postoperative margin assessment followed by adjuvant radiation therapy (RT). Sentinel lymph node biopsy is recommended in all patients with MCC without clinically detectable lymph nodes or distant metastasis. Adjuvant RT alone, eventually combined with complete lymph nodes dissection is proposed in case of micrometastatic nodal involvement. In case of macroscopic nodal involvement, the standard of care is complete lymph nodes dissection potentially followed by post-operative RT. Immunotherapy with anti-PD-(L)1 antibodies should be offered as first-line systemic treatment in advanced MCC. Chemotherapy can be used when patients fail to respond or are intolerant for anti-PD-(L)1 immunotherapy or clinical trials.

[Overtreatment of patients with basal cell carcinoma: active surveillance should be considered more often]. / Overbehandeling van patiënten met basaalcelcarcinoom.

Basal cell carcinoma (BCC) is the most common cancer type in the Netherlands and frequently diagnosed in older adults. Unlike other common forms of skin cancer (squamous cell carcinoma and melanoma), BCC generally grows slowly and the risk of metastasis and/or death is extremely small. In the first years after presentation, BCC often causes no or only minor complaints. Nevertheless, the vast majority of patients with BCC are treated immediately after diagnosis, usually with surgical excision. We think that overtreatment of patients with BCC is common and active surveillance may be an excellent alternative for patients with a limited life expectancy and should therefore be considered more often.

Long-Term Efficacy of Photodynamic Therapy with Fractionated 5-Aminolevulinic Acid 20% versus Conventional Two-Stage Topical Methyl Aminolevulinate for Superficial Basal-Cell Carcinoma.

BACKGROUND: Photodynamic therapy (PDT) is a noninvasive treatment for patients with superficial basal-cell carcinoma (sBCC). The efficacy of PDT may vary with different photosensitizers and treatment schedules. OBJECTIVE: Our objective was to evaluate whether fractionated 5-aminolevulinic acid 20% (ALA)-PDT is superior to conventional two-stage methyl aminolevulinate (MAL)-PDT for sBCC. METHODS: We present the 5 years results of a single-blind, randomized, multicenter trial. 162 patients with a histologically confirmed primary sBCC were randomized to fractionated ALA-PDT or MAL-PDT. RESULTS: The 5-year tumor-free survival rate was 70.7% (95% CI 58.2-80.1%) for ALA-PDT and 76.5% (95% CI 64.4-85.0%) for MAL-PDT. In the first 3 years, there was no significant difference in risk of treatment failure (HR = 1.53, p = 0.283), but in the long-term, the risk of recurrence was significantly lower following MAL-PDT compared to ALA-PDT (HR = 0.125, p = 0.049). As judged by patients, the esthetic result was good-excellent in 96.8% (61/63) and 94.4% (56/59) of patients treated with ALA-PDT and MAL-PDT, respectively (p = 0.631). CONCLUSION: The long-term efficacy is significantly higher for conventional two-stage MAL-PDT than for fractionated ALA-PDT, whereas there was no significant difference in esthetic outcome between the treatments at 5 years after treatment. These results indicate that fractionated ALA-PDT offers no benefit over conventional two-stage MAL-PDT.

European consensus-based interdisciplinary guideline for melanoma. Part 2: Treatment - Update 2022.

A unique collaboration of multidisciplinary experts from the European Dermatology Forum (EDF), the European Association of Dermato-Oncology (EADO), and the European Organization of Research and Treatment of Cancer (EORTC) was formed to make recommendations on cutaneous melanoma diagnosis and treatment, based on the systematic literature reviews and the experts' experience. Cutaneous melanomas are excised with one to 2-cm safety margins. Sentinel lymph node dissection shall be performed as a staging procedure in patients with tumor thickness ≥1.0 mm or ≥0.8 mm with additional histological risk factors, although there is as yet no clear survival benefit for this approach. Therapeutic decisions in stage III/IV patients should be primarily made by an interdisciplinary oncology team ("tumor board"). Adjuvant therapies can be proposed in stage III/completely resected stage IV patients and are primarily anti-PD-1, independent of mutational status, or alternatively dabrafenib plus trametinib for BRAF mutant patients. In distant metastases (stage IV), either resected or not, systemic treatment is always indicated. For first-line treatment particularly in BRAF wild-type patients, immunotherapy with PD-1 antibodies alone or in combination with CTLA-4 antibodies shall be considered. In stage IV melanoma with a BRAF-V600  E/K mutation, first-line therapy with BRAF/MEK inhibitors can be offered as an alternative to immunotherapy. In patients with primary resistance to immunotherapy and harboring a BRAF-V600  E/K mutation, this therapy shall be offered as second-line therapy. Systemic therapy in stage III/IV melanoma is a rapidly changing landscape, and it is likely that these recommendations may change in the near future.

European consensus-based interdisciplinary guideline for melanoma. Part 1: Diagnostics: Update 2022.

Cutaneous melanoma (CM) is potentially the most dangerous form of skin tumor and causes 90% of skin cancer mortality. A unique collaboration of multi-disciplinary experts from the European Dermatology Forum (EDF), the European Association of Dermato-Oncology (EADO) and the European Organization for Research and Treatment of Cancer (EORTC) was formed to make recommendations on CM diagnosis and treatment, based on systematic literature reviews and the experts' experience. The diagnosis of melanoma can be made clinically and shall always be confirmed with dermatoscopy. If a melanoma is suspected, a histopathological examination is always required. Sequential digital dermatoscopy and full body photography can be used in high-risk patients to improve the detection of early melanoma. Where available, confocal reflectance microscopy can also improve clinical diagnosis in special cases. Melanoma shall be classified according to the 8th version of the American Joint Committee on Cancer classification. Thin melanomas up to 0.8 mm tumor thickness do not require further imaging diagnostics. From stage IB onwards, examinations with lymph node sonography are recommended, but no further imaging examinations. From stage IIC onwards whole-body examinations with computed tomography (CT) or positron emission tomography CT (PET-CT) in combination with brain magnetic resonance imaging are recommended. From stage III and higher, mutation testing is recommended, particularly for BRAF V600 mutation. It is important to provide a structured follow-up to detect relapses and secondary primary melanomas as early as possible. There is no evidence to define the frequency and extent of examinations. A stage-based follow-up scheme is proposed which, according to the experience of the guideline group, covers the optimal requirements, but further studies may be considered. This guideline is valid until the end of 2024.

Risk of Invasive Cutaneous Squamous Cell Carcinoma After Different Treatments for Actinic Keratosis: A Secondary Analysis of a Randomized Clinical Trial.

Importance: Treatment of actinic keratosis (AK) aims to prevent cutaneous squamous cell carcinoma (cSCC). However, whether AK can progress into invasive cSCC is a matter of debate, and little is known about the effect of treatment on preventing cSCC. Objectives: To evaluate the risk of invasive cSCC and factors that may contribute to increased risk in patients with multiple AKs. Design, Setting, and Participants: In this secondary analysis of a multicenter randomized clinical trial, 624 patients with a minimum of 5 AKs within an area of 25 to 100 cm2 on the head were recruited from the Department of Dermatology of 4 hospitals in the Netherlands. Long-term follow-up was performed from July 1, 2019, to December 31, 2020. Interventions: Patients were randomized to treatment with 5% fluorouracil, 5% imiquimod cream, methylaminolevulinate photodynamic therapy, or 0.015% ingenol mebutate gel. Main Outcomes and Measures: The primary outcome was the proportion of patients with invasive cSCC in the target area during follow-up. Secondary outcomes were the associations between risk of invasive cSCC and a priori defined potential prognostic factors, including type of treatment, severity of AK (Olsen grade), history of nonmelanoma skin cancer, and additional treatment. Results: Of the 624 patients (558 [89.4%] male; median age, 73 years [range, 48-94 years]) in the study, 26 were diagnosed with a histologically proven invasive cSCC in the target area during follow-up. The total 4-year risk of developing cSCC in a previously treated area of AK was 3.7% (95% CI, 2.4%-5.7%), varying from 2.2% (95% CI, 0.7%-6.6%) in patients treated with fluorouracil to 5.8% (95% CI, 2.9%-11.3%) in patients treated with imiquimod. In patients with severe AK (Olsen grade III), the risk was 20.9% (95% CI, 10.8%-38.1%), and the risk was especially high (33.5%; 95% CI, 18.2%-56.3%) in patients with severe AK who needed additional treatment. Conclusions and Relevance: In this secondary analysis of a randomized clinical trial, risk of invasive cSCC was highest in patients with Olsen grade III AK and was substantially increased in patients who received additional treatment. These patients should be closely followed up after treatment. Trial Registration: ClinicalTrials.gov Identifier: NCT02281682.

Diagnostic Value of Optical Coherence Tomography Image Features for Diagnosis of Basal Cell Carcinoma.

Optical coherence tomography (OCT) is a non-invasive diagnostic method. Numerous morphological OCT features have been described for diagnosis of basal cell carcinoma (BCC). The aim of this study is to evaluate the diagnostic value of established OCT features and to explore whether the use of a small set of OCT features enables accurate discrimination between BCC and non-BCC lesions and between BCC subtypes. For each lesion, the presence or absence of specific OCT features was recorded. Histopathology was used as a gold standard. Diagnostic parameters were calculated for each OCT feature, and multivariate logistic regression analyses were performed to evaluate the loss in discriminative ability when using a small subset of OCT features instead of all features that are characteristic for BCC according to the literature. The results show that the use of a limited number of OCT features allows for good discrimination of superficial BCC from non-superficial BCC and non-BCC lesions. The prevalence of BCC was 75.3% (225/299) and the proposed diagnostic algorithm enabled detection of 97.8% of BCC lesions (220/225). Subtyping without the need for biopsy was possible in 132 of 299 patients (44%), with a predictive value for presence of superficial BCC of 84.3% vs 98.8% for presence of non-superficial BCC.

Topical Application of Glycerol Increases Penetration Depth of Optical Coherence Tomography in Diagnosis of Basal Cell Carcinoma.

Optical coherence tomography is a non-invasive imaging technique that enables high-resolution in vivo imaging of skin. Although optical coherence tomography is promising for diagnosing basal cell carcinoma, its limited penetration depth may impede basal cell carcinoma subtyping. This study evaluated whether topical application of glycerol can increase penetration depth and improve the image quality and visibility of characteristic features of basal cell carcinoma. A total of 61 patients with a total of 72 basal cell carcinomas were included. Optical coherence tomography scans were obtained before and after application of an 85% glyce-rol solution. The mean penetration depth of each optical coherence tomography scan was acquired by automatically tracing both skin surface and the point of signal loss using a custom-made MATLAB program. Mean ± standard deviation penetration depth increased from 883 ± 108 to 904 ± 88 µm before and after glycerol application, respectively (p = 0.005). Topical application of glycerol leads to a significant 2.4% increase in penetration depth. However, no significant differences in image quality and visibility of basal cell carcinoma features were found.