Photodynamic diagnosis of tumor margins using methyl aminolevulinate before Mohs micrographic surgery

Efficacy of PDD-guided tumor excision combined with photodynamic therapy in cutaneous squamous cell carcinoma

BACKGROUND

Cutaneous squamous cell carcinoma (cSCC) is an aggressive tumor with unclear margins. Photodynamic diagnosis (PDD) enables the differentiation of tumor tissue from normal tissue via visible fluorescence. Photodynamic therapy (PDT) is widely used in the treatment of non-melanoma skin tumors. This study aims to illustrate the efficacy and safety of PDD-guided tumor excision combined with ALA-PDT in patients with cSCC.

METHODS

This study involved 23 cSCC patients, randomly assigned to the PDD group (n = 11) and the non-PDD group (n = 12). Patients in the PDD group underwent tumor excision guided by PDD, while those in the non-PDD group received wide local excision (WLE). Both groups were subjected to frozen section analysis, and PDT was applied during and post-surgery.

RESULTS

The negative margin rate in the PDD group was 98.6 %, significantly higher than the 69.2 % observed in the non-PDD group. The PDD group required fewer frozen section analyses and experienced reduced surgical duration.

CONCLUSIONS

PDD effectively delineates tumor margins in cSCC, guiding the scope of surgical excision. The integration of PDD-guided resection with PDT offers a highly safe and effective therapeutic strategy for cSCC.

Applications and challenges of photodynamic therapy in the treatment of skin malignancies

Photodynamic Therapy (PDT), as a minimally invasive treatment method, has demonstrated its distinct advantages in the management of skin malignant tumors. This article examines the current application status of PDT, assesses its successful cases and challenges in clinical treatment, and anticipates its future development trends. PDT utilizes photosensitizers to interact with light of specific wavelengths to generate reactive oxygen species that selectively eradicate cancer cells. Despite PDT's exceptional performance in enhancing patients' quality of life and prognosis, the limitation of treatment depth and the side effects of photosensitizers remain unresolved issues. With the advancement of novel photosensitizers and innovative treatment technology, the application prospects of PDT are increasingly expansive. This article delves into the mechanism of PDT, its application in various skin malignancies, its advantages and limitations, and envisions its future development. We believe that through continuous technological enhancements and integration with other treatment technologies, PDT has the potential to assume a more pivotal role in the treatment of skin malignancies.

Neoadjuvant Photodynamic Therapy: An Updated Therapeutic Approach for Non-Melanoma Skin Cancers

OPINION STATEMENT

Non-melanoma skin cancers (NMSCs) are the most common malignancy and surgical excision is considered treatment of choice for the majority of cases. However, surgery can be very extensive in cases of large, multiple, or cosmetic-sensitive tumors located on areas such as scalp and face or genital region, leading to significant functional and cosmetic deficit. Aminolaevulinic acid photodynamic therapy (ALA-PDT) has emerged as a widely used approach in a variety of skin diseases, demonstrating remarkable efficacy in treatment of actinic keratosis, Bowen disease and basal cell carcinoma. Besides, when employed as a preoperative intervention, ALA-PDT effectively reduces tumor size and minimizes subsequent local surgical morbidity. With its minimally invasive nature and proven effectiveness, ALA-PDT holds significant promise as a neoadjuvant treatment option for NMSCs. In cases where the tumor is large, invasive, multiple, or located in cosmetically and functionally sensitive areas, or when considering patient factors such as age, comorbidity, willingness to undergo surgery, and post-operative quality-of-life, surgical intervention or radiotherapy alone may be impracticable or unacceptable. In such scenarios, neoadjuvant ALA-PDT can offer remarkable outcomes. In order to further ensure the maximum benefit of patients from neoadjuvant PDT, collaboration with multidisciplinary teams and whole-process management may be in need.

Photodynamic application in diagnostic procedures and treatment of non-melanoma skin cancers

OPINION STATEMENT

Skin tumors commonly seen in dermatology are involved in all layers of the skin and appendages. While biopsy of affected skin remains an essential method to confirm diagnosis and to predicate tumor prognosis, it has its limitations. Recently, photodynamic diagnosis (PDD) has demonstrated high sensitivity in detecting affected skin and mucosal tissues, providing valuable guidance for precision surgery to resect skin and mucosal tumors. In this review, we summarized the literatures concerning the applications of PDD in diagnostic process and treatment of skin and mucosal conditions such as actinic keratoses (AK), basal cell carcinoma (BCC), squamous cell carcinoma (SCC), Bowen's disease (BD) and extramammary Paget's disease (EMPD). The findings suggest that PDD holds substantial promise for expanding clinical applications and deserves further research exploration.

Fluorescent diagnostics of non-melanoma skin cancer

Fluorescent diagnostics is a promising method for diagnosing non-melanocytic skin tumors, which makes it possible to identify clinically undetectable skin cancer foci and clarify the margin of the tumor lesion. The main drugs for ‹uorescent diagnostics are drugs based on 5-aminolevulinic acid and its methyl ester. Sensitivity indicators of ‹uorescent diagnostics in basal cell, squamous cell carcinoma and extramammary Paget’s disease reach 79.0-100.0%, speci city – 55.6-100%. But the effectiveness of this method may be reduced due to hyperkeratinization, keratinization, and the presence of necrotic tissue on the surface of tumor foci. Comparative studies of the results of ‹uorescent diagnostics and histological mapping during tumor removal using Mohs micrographic surgery showed approximately equal results in the determining of the tumor edges by these methods, which indicates that safe and technically easily performed ‹uorescent diagnostics can serve as a good alternative to Mohs micrographic surgery, one of the most accurate, but rather labor-intensive and technically complex method for determining the margin of skin cancer foci.

Imaging technologies for presurgical margin assessment of basal cell carcinoma

Basal cell carcinoma is the most common cancer worldwide, necessitating the development of techniques to decrease treatment costs through efficiency and efficacy. Mohs micrographic surgery, a specialized surgical technique involving staged resection of the tumor with complete histologic evaluation of the peripheral margins, is highly utilized. Reducing stages by even 5% to 10% would result in significant improvement in care and economic benefits. Noninvasive imaging could aid in both establishing the diagnosis of suspicious skin lesions and streamlining the surgical management of skin cancers by improving presurgical estimates of tumor sizes. Herein, we review the current state of imaging techniques in dermatology and their applications for diagnosis and tumor margin assessment of basal cell carcinoma prior to Mohs micrographic surgery.

Thermo-Mechanical Fractional Injury Enhances Skin Surface- and Epidermis- Protoporphyrin IX Fluorescence: Comparison of 5-Aminolevulinic Acid in Cream and Gel Vehicles

BACKGROUND AND OBJECTIVES

Thermo-mechanical fractional injury (TMFI) impacts the skin barrier and may increase cutaneous drug uptake. This study investigated the potential of TMFI in combination with 5-aminolevulinic acid (ALA) cream and gel formulations to enhance Protoporphyrin IX (PpIX) fluorescence at the skin surface and in the skin.

STUDY DESIGN/MATERIALS AND METHODS

In healthy volunteers (n = 12) a total of 144 test areas were demarcated on the upper back. Test areas were randomized to (i) TMFI (6 milliseconds, 400 µm at a single pass) or no pretreatment and (ii) 20% ALA in cream or gel formulations. Skin surface PpIX fluorescence was quantified by PpIX fluorescence photography and photometry in 30-minute intervals until 3 hours. PpIX fluorescence microscopy quantified separate PpIX fluorescence in the epidermis, and in superficial-, mid-, and deep- dermis from punch biopsies sampled after 3 hours of ALA incubation. Local skin reactions (LSR) and pain intensities (numerical rating scale 0-10) were evaluated immediately, at 3 hours and 14 days after the intervention.

RESULTS

TMFI exposure before photosensitizer application significantly increased skin surface PpIX fluorescence, both for ALA cream (TMFI-ALA-cream 7848 arbitrary units [AU] vs. ALA-cream 5441 AU, 3 hours, P < 0.001) and ALA gel (TMFI + ALA-gel 4591 AU vs. ALA-gel 3723 AU, 3 hours, P < 0.001). The TMFI-mediated increase in PpIX fluorescence was similar for ALA-cream and -gel formulations (P = 0.470) at the skin surface. In the epidermis, PpIX fluorescence intensities increased from combination treatment with TMFI and ALA-cream (TMFI + ALA-cream 421 AU vs. ALA-cream 293 AU, P = 0.034) but not from combination with TMFI and ALA-gel (TMI + ALA-gel 264 AU vs. ALA-gel 261 AU, P = 0.791). Dermal fluorescence intensities (superficial-, mid-, or deep dermis) were unaffected by TMFI pretreatment in both ALA-cream and ALA-gel exposed skin (P = 0.339). ALA-cream generally induced higher PpIX fluorescence intensities than ALA-gel (skin surface P < 0.001 and epidermis P < 0.03). TMFI induced low pain intensities (median 3) and mild LSR that were resolved at 14 days follow-up.

CONCLUSION

Given the present study design, TMFI, in combination with the standardized application of 20% ALA cream and gel formulations, significantly enhanced skin surface PpIX fluorescence compared to no pretreatment. Additionally, TMFI increased epidermal PpIX fluorescence combined with 20% ALA cream vehicle. Thus, TMFI pretreatment and formulation characteristics exert influence on PpIX fluorescence intensities in normal skin. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

Delta-Aminolevulinic Acid-Mediated Photodiagnoses in Surgical Oncology: A Historical Review of Clinical Trials

Fluorescence imaging is an emerging clinical technique for real-time intraoperative visualization of tumors and their boundaries. Though multiple fluorescent contrast agents are available in the basic sciences, few fluorescence agents are available for clinical use. Of the clinical fluorophores, delta aminolevulinic acid (5ALA) is unique for generating visible wavelength tumor-specific fluorescence. In 2017, 5ALA was FDA-approved for glioma surgery in the United States. Additionally, clinical studies suggest this agent may have utility in surgical subspecialties outside of neurosurgery. Data from dermatology, OB/GYN, urology, cardiothoracic surgery, and gastrointestinal surgery show 5ALA is helpful for intraoperative visualization of malignant tissues in multiple organ systems. This review summarizes data from English-language 5ALA clinical trials across surgical subspecialties. Imaging systems, routes of administration, dosing, efficacy, and related side effects are reviewed. We found that modified surgical microscopes and endoscopes are the preferred imaging devices. Systemic dosing across surgical specialties range between 5 and 30 mg/kg bodyweight. Multiple studies discussed potential for skin irritation with sun exposure, however this side effect is infrequently reported. Overall, 5ALA has shown high sensitivity for labeling malignant tissues and providing a means to visualize malignant tissue not apparent with standard operative light sources.

Use of Protoporphyrin Fluorescence to Determine Clinical Target Volume for Non-melanotic Skin Cancers Treated with Primary Radiotherapy

PURPOSE 

Non-melanotic skin cancers remain the most commonly diagnosed cancers. Radiotherapy and surgery are the most common treatment options. Radiotherapy has a recurrence rate of up to 20% for basal or squamous cell cancers. One of the difficulties is to determine the extent of disease for poorly demarcated tumors. This study utilizes protoporphyrin (PpIX) fluorescence to provide information on the extent of subclinical disease for poorly demarcated tumors treated with radiotherapy.

MATERIALS AND METHODS 

For 33 patients, PpIX photo-delineation was used to determine the clinical target volume (CTV2), which was compared to current conventional margins used to account for microscopic disease.

RESULTS 

The use of PpIX photo-delineation demonstrated a significantly larger CTV of 15 mm compared to the conventional 10 mm (p = 0.03) for poorly demarcated lesions. A larger CTV was also demonstrated with PpIX photo-delineation for all basal cell carcinomas (13 mm, p = 0.03) as well as for non-nasal lesions (14 mm, p = 0.04). A trend towards an increased CTV was also noted for squamous cell carcinomas (16 mm, p = 0.19) and nasal primary sites (14 mm, p = 0.11). Nasal primary malignancies had multifocal PpIX uptake in 94% of cases. There was one case of local recurrence and one case of distant recurrence, with an average follow-up time of 22 months.

CONCLUSIONS 

The margins currently used to account for subclinical disease may underestimate the extent of microscopic spread for poorly demarcated tumors. Longer follow-up with larger pools of patients are necessary to determine if using PpIX photo-delineation translates into significantly improved clinical outcomes.

Can basal cell carcinoma lateral border be determined by fluorescence diagnosis?: Verification by Mohs micrographic surgery

BACKGROUND

The preferential accumulation of 5-aminolaevulinic acid (ALA)-induced protoporphyrin IX (PpIX) in neoplastic cells supports its potential use in the photodetection of epithelial tumours through porphyrin fluorescence.

OBJECTIVE

To assess the validity of fluorescence diagnosis (FD) as an efficient pre-surgical in vivo imaging tool for defining the lateral boundaries of various types of basal cell carcinomas (BCCs).

METHODS

The BCC tumour area was determined for 27 patients using FD digitalized imaging system, where the accumulation of PpIX in tumour tissue in relation to normal tissue was measured. Subsequently, BCCs were excised according to the complete area defined by FD using Mohs micrographic surgery (MMS).

RESULTS

Of the 27 BCCs, the FD margin of the lesion coincided with the histopathological picture in 12 BCCs (44.44%). The mean value of accumulation factor (AF) was 2.7. Although 17 pigmented BCCs showed attenuated or absent fluorescence in the center, fluorescence at their periphery was used as a guide for excision, and statistically, the pigmentation of the BCCs showed no effect on the results of the FD efficacy (p=1.0).

CONCLUSION

Fluorescence diagnosis of BCC may be beneficial as a guide to the safety margin needed before MMS. The safety margin is decided according to the FD tumour diameter in relation to the clinical tumour diameter.

Combined reflectance confocal microscopy-optical coherence tomography for delineation of basal cell carcinoma margins: an ex vivo study

We present a combined reflectance confocal microscopy (RCM) and optical coherence tomography (OCT) approach, integrated within a single optical layout, for diagnosis of basal cell carcinomas (BCCs) and delineation of margins. While RCM imaging detects BCC presence (diagnoses) and its lateral spreading (margins) with measured resolution of ∼1  μm, OCT imaging delineates BCC depth spreading (margins) with resolution of ∼7  μm. When delineating margins in 20 specimens of superficial and nodular BCCs, depth could be reliably determined down to ∼600  μm, and agreement with histology was within about ±50  μm.

Photodynamic Therapy Followed by Mohs Micrographic Surgery Compared to Mohs Micrographic Surgery Alone for the Treatment of Basal Cell Carcinoma: Results of a Pilot Single-Blinded Randomised Controlled Trial

Introduction:

Basal cell carcinoma is a common cutaneous malignant tumour. Surgical excision is the “gold standard” treatment for most subtypes, with Mohs micrographic surgery (MMS) offering the highest cure rate. Other treatment modalities used include photodynamic therapy (PDT).

Background:

We aimed to study the efficacy of combining MMS with PDT to see whether this would reduce the number of stages and final defect size when compared with MMS alone.

Materials and Methods:

Our study was a single-centre, single-blinded, randomised and controlled pilot study involving a total of 19 patients. Nine patients were randomised to pre-treatment with PDT followed by MMS of whom two withdrew; the remaining 10 patients were randomised to the MMS alone. Follow-up visits were arranged at 3 and 6 months post-surgery.

Results:

In the PDT arm, five out of the seven treated patients (71%) had their initial tumour size decreased following PDT treatment prior to MMS. The average number of stages in the PDT arm was 1.85, compared to 2.5 in the MMS arm. The average number of sections in the PDT arm was 4.2, in comparison to 5.2 in the MMS arm.

Conclusion:

Our pilot study showed a promising but limited role for PDT as an adjunct in MMS in the treatment of selected cases of basal cell carcinomas. Larger trials, preferably multi-centred are required to further examine the role of this combination therapy.

Intraoperative imaging during Mohs surgery with reflectance confocal microscopy: initial clinical experience

Mohs surgery for the removal of nonmelanoma skin cancers (NMSCs) is performed in stages, while being guided by the examination for residual tumor with frozen pathology. However, preparation of frozen pathology at each stage is time consuming and labor intensive. Real-time intraoperative reflectance confocal microscopy(RCM), combined with video mosaicking, may enable rapid detection of residual tumor directly in the surgical wounds on patients. We report our initial experience on 25 patients, using aluminum chloride for nuclear contrast. Imaging was performed in quadrants in the wound to simulate the Mohs surgeon’s examination of pathology. Images and videos of the epidermal and dermal margins were found to be of clinically acceptable quality. Bright nuclear morphology was identified at the epidermal margin and detectable in residual NMSC tumors. The presence of residual tumor and normal skin features could be detected in the peripheral and deep dermal margins. Intraoperative RCM imaging may enable detection of residual tumor directly on patients during Mohs surgery, and may serve as an adjunct for frozen pathology. Ultimately, for routine clinical utility, a stronger tumor-to-dermis contrast may be necessary, and also a smaller microscope with an automated approach for imaging in the entire wound in a rapid and controlled manner.

Spotlighting the role of photodynamic therapy in cutaneous malignancy: an update and expansion

BACKGROUND

Topical photodynamic therapy (PDT) is an option for the treatment of cutaneous malignancy.

OBJECTIVE

To present an update and expansion on a previous review of the use of PDT in the current literature in the treatment of actinic keratoses (AK), superficial and nodular basal cell carcinoma (sBCC, nBCC), squamous cell carcinoma (SCC), Bowen's disease, cutaneous T cell lymphoma (CTCL), malignant melanoma, and its use in chemoprevention.

METHODS

Extensive PubMed search January 2013.

RESULTS AND CONCLUSIONS

We find sufficient evidence to recommend the use of PDT in certain patients in the treatment of AK, Bowen's disease, sBCC, and nBCC. It is especially useful in those with contraindications to surgery, widespread areas of involvement, and large lesions. Not only can it be considered superior to other therapies as far as recovery time, tolerance, and cosmetic outcomes, but it also should be considered, when indicated, as first-line treatment in the above conditions. Investigations continue for the use of PDT in the treatment of melanoma, SCC, chemoprevention, and CTCL.

Efficacy of photodynamic diagnosis-guided Mohs micrographic surgery in primary squamous cell carcinoma

BACKGROUND

Cutaneous squamous cell carcinoma (cSCC) usually has ill-defined margins because of its irregular invasive patterns.

OBJECTIVE

To evaluate the surgical efficacy of photodynamic diagnosis (PDD) in primary cSCC treated using Mohs micrographic surgery (MMS).

METHODS & MATERIALS

We examined 67 cases of biopsy-proven primary facial cSCC treated with MMS. The 67 SCC were divided into the two groups depending on PDD application: PDD group (n = 38, 56.7%) and non-PDD group (n = 29, 43.3%). We analyzed the differences in surgical features between the PDD and non-PDD groups.

RESULTS

The PDD group required fewer Mohs stages (1.37 vs 1.83, p = .02) and smaller surgical margins (8.03 vs 11.24 mm, p = .03). PDD showed additional benefits in terms of surgical margin and Mohs stage, especially in low-risk SCC, including thin (≤4 mm), small (≤20 mm), well-differentiated, and nonulcerative tumors (p < .05) but did not show beneficial effects in high-risk SCC (p > .05) during MMS.

CONCLUSION

PDD can increase surgical efficacy of primary cSCC during MMS. These benefits are more pronounced in low-risk SCC. We recommend PDD as a simple and useful technique for delineating the margins of low-risk SCC before MMS.

[Fluorescence diagnosis of non-melanoma skin cancer]

Photodynamic therapy involves - in dermatological practice usually exogenous - application of a photosensitizer then activation of accumulated protoporphyrin IX by light with an appropriate wavelength after a short incubation period. It is an evidence based method to treat certain non-melanoma skin cancers. During treatment when the excited protoporphyrin IX returns to base state, reactive oxygen species are formed leading to cell death in rapidly proliferating cells. Fluorescence of excited protoporphyrin IX can be used in diagnostics as well. In ultraviolet light, the photodamaged or neoplastic areas show coral red fluorescence which can clearly be distinguished from the much lower fluorescence of adjacent normal tissue. This process is suitable for exact determination of tumor margins so it can be used for planning surgical procedures or after photodynamic therapy at a follow up visit for the visualization of the therapeutic result. The present article reviews the literature of photodynamic diagnosis that is also used by the authors.

The application of Levulan-based photodynamic therapy with imiquimod in the treatment of recurrent basal cell carcinoma

BACKGROUND

Common skin tumors like basal- and squamous-cell carcinoma present a serious problem in modern medicine. Exposure to ultraviolet solar radiation is the main cause of these lesions. Since application of Aldara and PDT separately is well documented, we decided to use both methods together. The aim of our study was to evaluate the effectiveness of local photodynamic therapy supplemented with topical application of Aldara in basal-cell carcinoma.

MATERIAL/METHODS

Thirty-four patients ages 50 to 68 years were enrolled to the trial and underwent PDT treatment. Each case of BCC was histopathologically confirmed. Ten patients were subjected to local Levulan-PDT and placebo (Eucerin as vehicle cream), and 24 patients were subjected to Levulan-PDT and imiquimod. Photodynamic diagnosis (PDD) was used to detect and visualize suspicious foci (including cancer lesions).

RESULTS

In the group of patients who were treated using Levulan-PDT and placebo, 6 patients (60%) were totally cured and 4 lesions (40%) significantly decreased in size. In the group of patients treated with Levulan-PDT and imiquimod, 18 lesions totally disappeared (75%), 6 lesions significantly diminished, and in 1 patient small foci of previously excised BCC developed again in scar tissue 10 month after the first control examination.

CONCLUSIONS

Cure was achieved without any scarring and with very good cosmetic effects. Although this is the preliminary report, the presented modification of PDT seems to be reasonable and promising in treating basal-cell carcinoma.