Experience and BCC subtypes as determinants of MAL-PDT response: Preliminary results of a national Brazilian project

Photodynamic Therapy in Pigmented Basal Cell Carcinoma-A Review

This review summarizes the effectiveness of photodynamic therapy (PDT) in the treatment of the pigmented subtype of basal cell carcinoma (BCC) based on the current literature. PDT is a light-activated treatment, non-invasive, that selectively destroys tumor cells and tissues via the interaction of a photosensitizer, light, and molecular oxygen. It can induce cancer cell death through direct tumor vascular damage or via the induction of immune response. However, human skin is also an absorption and scattering medium since it contains hemoglobin and melanin that act as chromophores. Eumelanin can be considered a light-absorber and an intracellular antioxidant that can neutralize PDT-induced ROS and, therefore, decrease PDT success. Various factors, including tumor depth, the degree of pigmentation in malignant cells, and the individual's skin phototype, can impact the outcome of this intricate biochemical process. It has been widely recognized that PDT exhibits limited efficacy in the treatment of pigmented lesions. However, new combination techniques such as curettage or debulking before PDT show promising results in the treatment of pigmented BCC.

Clinical and histopathologycal study of actinic keratosis treatment with photodynamic therapy VS 5-fluorouracil in face cancerization field

Actinic keratosis (AK) is one of the most frequent pathologies in clinical practice. The prevalence varies according to the area of incidence and age. Approximately 10% of the prevalence of AK occurs at 30 years of age and rises to 80% at 70 years of life. This study conducted a split-face analysis based on Photodynamic Therapy (MALA-PDT) and 5-fluorouracil (5-FU) treatments in patients with AK. Clinical and histopathological studies evaluated each treatment's efficiency and side effects. Six patients were recruited between 50 and 70 years of age for this. MALA-PDT was applied on the right side of the face. A biodistribution time of 2 hours, a dose of light of 36 J / cm² (20 min irradiation), a spot for photoirradiation with a total area of 100 cm², and a wavelength of 635 nm were used. (LINCE equipment MMOPTICS-Brazil). By fluorescence diagnosis, clinical and subclinical AK lesions were evidenced in the area called the "cancerization field." Two cycles of MALA-PDT were performed on each patient, and 5-FU was applied twice daily for 15 days. A 2-month follow-up post-MALA-PDT and post-5-FU was carried out. The treatment based on 5-Flu and MALA-PDT clinically shows the same response, but MALA-PDT is less aggressive than 5-FU. The treatment of AK based on MALA-PDT is a practical, cheap, and easy-to-use technique.

RANDOMIZED CONTROLLED TRIAL FOR EVALUATION OF EFFICACY AND PAIN DURING PHOTODYNAMIC THERAPY FOR ACTINIC KERATOSIS OF FACE AND SCALP COMPARING TWO IRRADIATION PROTOCOLS

BACKGROUND

Pain is a frequent adverse event during photodynamic therapy, which can limit treatment acceptance. This study aimed to evaluate the efficacy and pain during photodynamic therapy with two irradiation protocols in patients with actinic keratosis on the face and scalp.

METHODS

In this intra-patient randomized controlled trial, participants were randomly allocated to receive photodynamic therapy with methyl aminolevulinate and red light on the right or left side with protocol 1 (irradiation device in contact with the skin) and protocol 2 (device 3 cm away from the skin). There was a 15-day interval between the protocols. The primary outcome was the frequency of mean intensity of moderate or severe pain during photodynamic therapy. Secondary outcomes were actinic keratosis clearance rate, protoporphyrin IX consumption, participant preference, skin appearance, and adverse events.

RESULTS

Forty-one participants were included, yielding 47 and 50 randomized sites for protocols 1 and 2. There was no difference in the frequency of moderate and severe pain, with a relative risk of 1.09 (95% CI 0.70-1.70), p>0.05. An actinic keratosis count reduction >60% was observed in both protocols (p<0.01), with no difference between them. There was no difference in protoporphyrin IX consumption. Most treated sites were of good to excellent quality. There was a greater patient preference for protocol 2 (p<0.01).

CONCLUSIONS

The pain intensity was similar between the protocols, and the protocols were equally effective for actinic keratosis clearance, protoporphyrin IX consumption, and improvement in the quality of the treated areas. Both protocols can be considered safe.

Methyl aminolevulinate photodynamic therapy after partial debulking in the treatment of superficial and nodular basal cell carcinoma: 3-years follow-up

BACKGROUND

The increase in the number of basal cell carcinoma (BCC) lesions has prompted use of minimally invasive therapies, including Photodynamic therapy (PDT). . The objective of the present work was to analyze the efficacy of methyl aminolevulinate-mediated photodynamic therapy (MAL-PDT) in patients suffering from superficial or nodular BCCs.

METHODS

A total of 220 BCC lesions (76 superficial and 144 nodular), clinically diagnosed and confirmed by histopathology analysis, were treated in 174 patients (mean age 72.5). Debulking using curettage was performed before two or three MAL-PDT sessions (λ = 630 nm; 90 J/cm²; 23 min) at 4-week intervals. Analyses of clinical clearance and cosmetic outcome were carried out by direct examination, dermoscopy, photographs, as well as by fluorescence diagnosis using a Wood's lamp. Evaluations were carried out at the different PDT sessions and follow-ups over a 3-year period.

RESULTS

MAL-PDT was safe and highly tolerated. After an average of 2.6 MAL-PDT sessions, the overall clearance rate at 3-year follow-up was 96.1 % (95 % confidence interval [CI] 100 %-92 %) for superficial BCCs and 95.2 % (95 % [CI] 99 %-92 %) for nodular BCCs after an average of 2.7 sessions. Minimal side effects such as crushing, erythema and edema were reported. All BCC lesions showed excellent or good cosmetic results.

CONCLUSION

The protocol followed in the present study has shown that MAL-PDT is a safe and effective treatment for superficial and nodular types of BCC.

Photodynamic therapy as a treatment option for multiple pigmented basal cell carcinoma: Long-term follow-up results

Photodynamic therapy (PDT) has been used worldwide as a non-surgical option for the treatment of basal cell carcinoma (BCC). PDT treatment for pigmented BCC is not frequently performed because of poorer results, which are explained by lower penetration of the light, possibly related to the melanin absorption in the visible range wavelengths. However, there is evidence for an increase in PDT cure rates with prior debulking of the lesion. In this study, we reported a complete clearance of 30 pigmented basal cell carcinomas in 2 patients. PDT was performed in a single visit protocol, which consists of two illumination sessions performed on the same day (125 mW/cm² of irradiance and 150 J/cm² of fluence). Imediately after the debulking of the BCC, a 20 % methyl aminolevulinate cream was applied and occluded for 3 h in the first session and 1.5 h in the second. After 30 days of the treatment, all regions were evaluated clinically and histologically, showing no residual BCC. Even with long-term follow-up (mean of 24 months), no recurrence was detected.. This PDT protocol achieved 100 % control for pigmented BCC. Therefore, it was demonstrated that PDT may be a successful treatment option for small and multiple pigmented BCC.

The application of physical pretreatment in photodynamic therapy for skin diseases

Photodynamic therapy (PDT) is widely used in skin diseases; the response rate of PDT treatment varies widely. The limited penetration in the tissue of photosensitizers influenced the penetration depth of PDT, which obviously impacts the therapeutic effect. The studies have improved the efficacy of PDT through various pretreatment applications; especially, the physical pretreatment had achieved significant outcomes. We will review the physical pretreatment to optimize the efficacy of PDT in skin diseases by searching the literature on this topic. The types of physical pretreatment commonly used in the clinical practice are discussed: curettage, superficial shaving, laser, surgical resection, plum-blossom needles, and microneedles. Compared with PDT alone, the physical pretreatment before PDT application was generally improved the efficacy and reduced the recurrence, especially in actinic keratoses (AK), Bowen disease (BD), basal cell carcinoma (BCC), and viral warts. The application of the physical pretreatments before PDT may improve the efficacy of PDT in various skin diseases. However, each kind of physical pretreatment has the benefit and shortcoming, and the applicable situation is different.

Dissolving microneedles containing aminolevulinic acid improves protoporphyrin IX distribution

One important limitation of topical photodynamic therapy (PDT) is the limited tissue penetration of precursors. Microneedles (MNs) are minimally invasive devices used to promote intradermal drug delivery. Dissolving MNs contain drug-associated to polymer blends, dissolving after insertion into skin, allowing drug release. This study comprises development and characterization of a pyramidal model of dissolving MNs (500 μm) prepared with 5% wt/wt aminolevulinic acid and 20% wt/wt Gantrez AN-139 in aqueous blend. Protoporphyrin IX formation and distribution were evaluated in tumor mice model by using fluorescence widefield imaging, spectroscopy, and confocal microscopy. MNs demonstrated excellent mechanical resistance penetrating about 250 μm with minor size alteration in vitro, and fluorescence intensity was 5-times higher at 0.5 mm on average compared to cream in vivo (being 10 ± 5 a.u. for MNs and 2.4 ± 0.8 a.u. for cream). Dissolving MNs have overcome topical cream application, being extremely promising especially for thicker skin lesions treatment using PDT.

Treatment of superficial basal cell carcinoma with 7.8% 5-aminolaevulinic acid nanoemulsion-based gel (BF-200 ALA) and photodynamic therapy: Results in clinical practice in a tertiary hospital

Photodynamic therapy (PDT) is an effective treatment option for the treatment of superficial basal cell carcinoma (sBCC). Recent publications have demonstrated that PDT with 7.8% 5-aminolaevulinic acid nanoemulsion-based gel (BF-200 ALA-PDT) is an effective and safe alternative for the treatment of sBCC). To investigate the efficacy and safety of 7.8% 5-aminolaevulinic acid nanoemulsion-based gel (BF-200 ALA)-PDT for the treatment of sBCC. A non-controlled, open-label single centre study was conducted. Patients received one PDT cycle with two PDT sessions one-week apart. In case that clinical-dermoscopy evaluation of treatment outcome revealed remaining lesions, a second PDT cycle was performed. The clinical results at the dermoscopy and fluorescence diagnosis level were histologically confirmed in all patients. Treatment response was evaluated 3, 6, and 12 months after last PDT session. A total of 31 patients (12 men and 19 women), with a median age of 63.74 years were included in this study. 3-month after PDT-session, 23/31 patients were complete responders (74.19%) after two BF-200 ALA -PDT sessions. Esthetic outcome was considered good-to-excellent. 5 Aminolevulinic acid 7.8% nanoemulsion-based gel (BF-200 ALA) PDT is an effective therapy option for the treatment of sBCC. Complete clearance rates were higher in those patients who received only one PDT cycle. These results show a similar tendency as shown in other publications.

Photodynamic Therapy for Basal Cell Carcinoma: The Clinical Context for Future Research Priorities

Photodynamic therapy (PDT) is an established treatment option for low-risk basal cell carcinoma (BCC). BCC is the most common human cancer and also a convenient cancer in which to study PDT treatment. This review clarifies challenges to researchers evident from the clinical use of PDT in BCC treatment. It outlines the context of PDT and how PDT treatments for BCC have been developed hitherto. The sections examine the development of systemic and subsequently topical photosensitizers, light delivery regimens, and the use of PDT in different patient populations and subtypes of BCC. The outcomes of topical PDT are discussed in comparison with alternative treatments, and topical PDT applications in combination and adjuvant therapy are considered. The intention is to summarize the clinical relevance and expose areas of research need in the BCC context, ultimately to facilitate improvements in PDT treatment.

MAL-associated methyl nicotinate for topical PDT improvement

Photosensitization of all tissue in sufficient quantity to generate damage is one of the limiting factors for Photodynamic Therapy (PDT) efficiency. Methyl nicotinate (MN) is a thermogenic and vasodilating substance that facilitates the topical tissue penetration of some compounds. The topical MAL (methyl aminolevulinate) PDT is commonly used as a precursor of protoporphyrin IX (PpIX). This study investigates the safety of topical use in NM, as well as its ability to improve the efficiency of topical PDT. For this, we investigate the cytotoxicity of MN, as well as its actions in increasing cellular metabolism and vasodilation. Besides, its ability to optimize the formation of PpIX in the tissue when associated with MAL cream was investigated, besides assessing the severity of necrosis obtained by treatments. The cytotoxicity of MN was tested for concentrations of 0, 0.1, 0.25, 0.5, 0.75 and 1% in cell culture. For the concentration of 0.5%, the cellular metabolism was evaluated using confocal microscopy to calculate the redox rate. In the Chorioallantoic Membrane Model, vasodilation was evaluated for concentrations of 0.5 and 1% MN during 1 h of incubation. In the animal model, the healthy skin of Wistar rat was used to evaluate the production of PpIX in the tissue and the degree of necrosis obtained by Photodynamic therapy when using NM associated with methyl aminolevulinate. It was observed the non-cytotoxicity in vitro of MN in the concentration used (0.5%) and its ability to increase cellular metabolism. In a chorioallantoic model, the MN vasodilation power was demonstrated for different caliber of vessels. In vivo studies are showing that the incorporation of MN in the MAL cream increases the amount of PpIX produced in the tissue causing a higher effect on the epidermis after PDT. This improvement of the protocol may make the procedure more effective both in the destruction of tumor tissue and in the treatment of deeper cells decreasing possible recurrence, in addition to allowing improvements in the protocol, such as reducing the cream's incubation time.

Optical clearing agent increases effectiveness of photodynamic therapy in a mouse model of cutaneous melanoma: an analysis by Raman microspectroscopy

Melanoma is the most aggressive type of skin cancer and a relevant health problem due to its poor treatment response with high morbidity and mortality rates. This study, aimed to investigate the tissue changes of an improved photodynamic therapy (PDT) response when combined with optical clearing agent (OCA) in the treatment of cutaneous melanoma in mice. Photodithazine (PDZ) was administered intraperitoneally and a solution of OCA was topically applied before PDT irradiation. Due to a resultant refractive index matching, OCA-treated tumors are more optically homogenous, improving the PDT response. Raman analysis revealed, when combined with OCA, the PDT response was more homogenous down to 725 µm-depth in thickness.

Dual-Agent Photodynamic Therapy with Optical Clearing Eradicates Pigmented Melanoma in Preclinical Tumor Models

Treatment using light-activated photosensitizers (photodynamic therapy, PDT) has shown limited efficacy in pigmented melanoma, mainly due to the poor penetration of light in this tissue. Here, an optical clearing agent (OCA) was applied topically to a cutaneous melanoma model in mice shortly before PDT to increase the effective treatment depth by reducing the light scattering. This was used together with cellular and vascular-PDT, or a combination of both. The effect on tumor growth was measured by longitudinal ultrasound/photoacoustic imaging in vivo and by immunohistology after sacrifice. In a separate dorsal window chamber tumor model, angiographic optical coherence tomography (OCT) generated 3D tissue microvascular images, enabling direct in vivo assessment of treatment response. The optical clearing had minimal therapeutic effect on the in control, non-pigmented cutaneous melanomas but a statistically significant effect (p < 0.05) in pigmented lesions for both single- and dual-photosensitizer treatment regimes. The latter enabled full-depth eradication of tumor tissue, demonstrated by the absence of S100 and Ki67 immunostaining. These studies are the first to demonstrate complete melanoma response to PDT in an immunocompromised model in vivo, with quantitative assessment of tumor volume and thickness, confirmed by (immuno) histological analyses, and with non-pigmented melanomas used as controls to clarify the critical role of melanin in the PDT response. The results indicate the potential of OCA-enhanced PDT for the treatment of pigmented lesions, including melanoma.

The effectiveness of photodynamic therapy and cryotherapy on patients with basal cell carcinoma: A systematic review and meta-analysis

Basal cell carcinoma (BCC) is known as the most common type of nonmelanoma skin cancer worldwide. The aim of this study is to show the effectiveness of photodynamic therapy and cryotherapy in patients with BCCs with the use of meta-analyses in order to see if there is a possible superiority of one treatment over the other. We searched the databases PubMed, MEDLINE, CINAHL, Scopus, OVID, Embase, Science Direct, JAMA Dermatology, and Research Gate in April 2020. The search combined related terms for cryotherapy, BCC, cryosurgery, cryoablation, laser and photodynamic therapy. The comparison of photodynamic therapy (PDT) vs cryotherapy on recurrence rate yielded no statistically significant results (Figure 2; N = 3 randomized control trials [RCTs]; Summary Random Effects OR = 4.99; P = .212). We observed large heterogeneity (I² = 87.3%), but no indication for small study effects (Egger's test, P = .02). Regarding the comparison of PDT vs cryotherapy on complete response, again no statistically significant results were observed (Figure 3; N = 2 RCTs; Summary Fixed Effects OR = 0.83; P = .538) and no indication of heterogeneity (I² = 0%). Our meta-analyses indicated that the comparison of PDT vs cryotherapy has no statistically significant results. Therefore, these therapies seem to have similar therapeutic effects.

Overall Results for a National Program of Photodynamic Therapy for Basal Cell Carcinoma: A Multicenter Clinical Study to Bring New Techniques to Social Health Care

Along the past years, a national program to implement photodynamic therapy (PDT) for nonmelanoma skin cancer (NMSC) was performed over the Brazilian territory. Using a strategy involving companies, national bank, and medical partners, equipment, medication, and protocols were tested in a multicenter study. With results collected over 6 years, we could reach a great deal of advances concerning the use of PDT for skin cancer. We present the overall reached results of the program and discuss several aspects about it, including public politics of treatment. A discussion about advantages of this technique within conditions of health care is placed, comparing PDT with surgery, including an analysis about the implementation of PDT in countries in development as Brazil, considering not only technical but social aspects, as the distribution of medical doctor in the Brazilian territory. The program resulted in a huge dissemination of PDT in Brazil and many countries in Latin America, in a partnership among public politics, universities, companies, and hospitals and clinics and in the insertion of national technologies as option to treat NMSC. Consequence of the program is mainly the continuation of the use of PDT in Brazil and many countries in Latin America.

Optical coherence angiography for pre-treatment assessment and treatment monitoring following photodynamic therapy: a basal cell carcinoma patient study

Microvascular networks of human basal cell carcinomas (BCC) and surrounding skin were assessed with optical coherence angiography (OCA) in conjunction with photodynamic therapy (PDT). OCA images were collected and analyzed in 31 lesions pre-treatment, and immediately/24 hours/3-12 months post-treatment. Pre-treatment OCA enabled differentiation between prevalent subtypes of BCC (nodular and superficial) and nodular-with-necrotic-core BCC subtypes with a diagnostic accuracy of 78%; this can facilitate more accurate biopsy reducing sampling error and better therapy regimen selection. Post-treatment OCA images at 24 hours were 98% predictive of eventual outcome. Additional findings highlight the importance of pre-treatment necrotic core, vascular metrics associated with hypertrophic scar formation, and early microvascular changes necessary in both tumorous and peri-tumorous regions to ensure treatment success.

Field cancerization treatment using topical photodynamic therapy: A comparison between two aminolevulinate derivatives

The objective of this study was to evaluate and compare the clinical response to PDT (Photodynamic Therapy) in field cancerization using two aminolevulinate derivatives. Forty patients with multiple actinic keratosis (AK) on forearms and hands scattered received two sessions of ALA and MAL-PDT at 630 nm (36 J/cm²). The AK clearance rate was 72 % for both drugs with a significant decrease in AK observed clinically (p < 00,001). Clinical improvement in field cancerization using two aminolevulinate derivatives in PDT is proven with no significant difference in the efficacy of drugs.

Energy analysis of PDT using thermography during the treatment of basal cell carcinoma

The changes in tissue temperature of basal cell carcinoma lesions were investigated during photodynamic therapy in order to better understand the effects and mechanisms of PDT in tissue. In this study, the monitoring of 40 lesions of basal cell carcinoma was performed during photodynamic therapy. The lesion region becomes thermally evident throughout the procedure, and there is an improved contrast of the lesion edges after the end of the irradiation. The comparison between thermal and fluorescence images showed a correlation between the PpIX evidenced through widefield fluorescence and the temperature gradient of the thermal images after the procedure, indicating that thermography is a potential diagnostic tool to evaluate the selective response of PDT. A model was created to calculate the amount of light energy converted to heat, tissue damage, and other energy transfer processes involved in the PDT. Using this model, it was shown that most of the energy conversion was in photodynamic action (48.7% and 48.3%, in first and second session, respectively), followed by the energy ratio attributable to blood perfusion (37.2%). This is evidence that photodynamic therapy does not generate a significant thermal component, an important aspect of the study of its mechanisms.

Long Term Effectiveness of Photodynamic Therapy for CIN Treatment

(1) Background: Cervical cancer is the third most commonly diagnosed cancer and the fourth leading cause of cancer death in women worldwide. The highest incidence rates are in Africa, followed by South-Central Asia and South America. According to the Brazilian National Institute of Cancer (INCA), 16,370 new cases of cervical cancer were estimated for each year of the biennium of 2018-2019. About 90% of cervical cancers originate from the malignant progression of cervical intraepithelial neoplasia (CIN) which is classified based on cytohistological characteristics (low- and high-grade lesions). The present study reports the long-term effectiveness of topical photodynamic therapy (PDT) for CIN grades 1 and 2/3 with up to two years of follow up. (2) Methods: A total of 56 patients with CIN 1, ten with CIN 2, and 14 patients for the placebo group were enrolled in this study. (3) Results: 75% (n = 42) of CIN 1 patients presented a complete response to PDT and only 23.2% (n = 13) of recurrence, progression, and/or lesions remaining two years after PDT. For CIN 2/3 patients, 90% were observed to be cured after one and two years of follow up. (4) Conclusions: PDT presented best results two years after a non-invasive, fast, and low-cost procedure and in comparison with the placebo group, preventing the progression of cervical intraepithelial neoplasia and preserving the cervix.

Raman Microspectroscopy as a Tool to Elucidate the Efficacy of Topical Formulations Containing Curcumin

The success of the onychomycosis treatment is directly associated with factors such as the choice of the medication, the administration route, and the pharmaceutical formulation. Photodynamic therapy (PDT) is an emerging and promising technique indicated for onychomycosis treatment. For this application, the main challenge is the efficient delivery of the photosensitizer (PS). Curcumin is widely used as a PS, however it is an unstable molecule and it is a challenge to develop a formulation with good penetration into the nail plate, maintaining the stability of curcumin. In this study, the molecular mechanisms underlying the efficacy of two topical formulations containing curcumin used in a clinical trial for onychomycosis treatment were analyzed by Raman microspectroscopy. It is shown that curcumin is present in both formulations in aggregated and non-aggregated states, and in aggregates it is present in different conformations, depending on the interaction with the solvent. This proves to be critical for efficient and uniform PS delivery to the nail and its complete use during the treatment. These analyses are showing how promising Raman microspectroscopy is in understanding the molecular mechanisms of the efficiency of photosensitizers and are helping to improve the development of pharmaceutical formulations.

Topical and intradermal delivery of PpIX precursors for photodynamic therapy with intense pulsed light on porcine skin model

In order to purposely decrease the time of the photodynamic therapy (PDT) sessions, this study evaluated the effects of PDT using topical and intradermal delivery of two protoporphyrin (PpIX) precursors with intense pulsed light (IPL) as irradiation source. This study was performed on porcine skin model, using an IPL commercial device (Intense Pulse Light, HKS801). IPL effect on different administration methods of two PpIX precursors (ALA and MAL) was investigated: a topical cream application and an intradermal application using a needle-free, high-pressure injection system. Fluorescence investigation showed that PpIX distribution by needle-free injection was more homogeneous than that by cream, suggesting that a shorter drug-light interval in PDT protocols is possible. The damage induced by IPL-PDT assessed by histological analysis mostly shows modifications in collagens fibers and inflammation signals, both expected for PDT. This study suggested an alternative protocol for the PDT treatment, possibility half of the incubation time and with just 3 min of irradiation, making the IPL-PDT, even more, promising for the clinical treatment.

Optical techniques for the diagnosis and treatment of lesions induced by the human papillomavirus - A resource letter

Human papillomaviruses (HPV) are the most common sexually-transmitted virus, and carcinogenic HPV strains are reported to be responsible for virtually all cases of cervical cancer and its precursor, the cervical intraepithelial neoplasia (CIN). About 30% of the sexually active population are considered to be affected by HPV. Around 600 million people are estimated to be infected worldwide. Diseases related to HPV cause significant impact from both the personal welfare point of view and public healthcare perspective. This resource letter collects relevant information regarding HPV-induced lesions and discusses both diagnosis and treatment, with particular attention to optical techniques and the challenges involved to the implementation of those approaches.

The use of dermatoscopy in diagnosis and therapy of nonmelanocytic skin cancer

Today, dermatoscopy is an integral part of every clinical skin examination, as it markedly enhances the early detection of melanocytic and nonmelanocytic skin cancer (NMSC) compared to naked-eye inspection. Besides its diagnostic use, this noninvasive method is increasingly important in the selection of as well as the response assessment to various therapies used for NMSC, including basal cell carcinoma, actinic keratoses, squamous cell carcinoma, and also rare tumors such as Merkel cell carcinoma, angiosarcoma, or dermatofibrosarcoma protuberans. Thus, dermatoscopy is a valid tool for the preoperative assessment of tumor margins in basal cell carcinoma, but also for follow-up of actinic keratoses after topical treatment. The present article presents an overview on the use of dermatoscopy in the diagnosis and therapy of various types of NMSC.

Optical clearing of melanoma in vivo: characterization by diffuse reflectance spectroscopy and optical coherence tomography

Melanoma is the most aggressive type of skin cancer, with significant risk of fatality. Due to its pigmentation, light-based imaging and treatment techniques are limited to near the tumor surface, which is inadequate, for example, to evaluate the microvascular density that is associated with prognosis. White-light diffuse reflectance spectroscopy (DRS) and near-infrared optical coherence tomography (OCT) were used to evaluate the effect of a topically applied optical clearing agent (OCA) in melanoma in vivo and to image the microvascular network. DRS was performed using a contact fiber optic probe in the range from 450 to 650 nm. OCT imaging was performed using a swept-source system at 1310 nm. The OCT image data were processed using speckle variance and depth-encoded algorithms. Diffuse reflectance signals decreased with clearing, dropping by ∼ 90% after 45 min. OCT was able to image the microvasculature in the pigmented melanoma tissue with good spatial resolution up to a depth of ∼ 300 μm without the use of OCA; improved contrast resolution was achieved with optical clearing to a depth of ∼ 750 μm in tumor. These findings are relevant to potential clinical applications in melanoma, such as assessing prognosis and treatment responses. Optical clearing may also facilitate the use of light-based treatments such as photodynamic therapy.

Resistance of Nonmelanoma Skin Cancer to Nonsurgical Treatments. Part II: Photodynamic Therapy, Vismodegib, Cetuximab, Intralesional Methotrexate, and Radiotherapy

A wide range of treatments is now available for nonmelanoma skin cancer, including 5-fluorouracil, ingenol mebutate, imiquimod, diclofenac, photodynamic therapy, methotrexate, cetuximab, vismodegib, and radiotherapy. All are associated with high clinical and histologic response rates. However, some tumors do not respond due to resistance, which may be primary or acquired. Study of the resistance processes is a broad area of research that aims to increase our understanding of the nature of each tumor and the biologic features that make it resistant, as well as to facilitate the design of new therapies directed against these tumors. In this second article, having covered the topical treatments of nonmelanoma skin cancer, we review resistance to other nonsurgical treatments, such as monoclonal antibodies against basal and squamous cell carcinomas, intralesional chemotherapy, photodynamic therapy, and radiotherapy.

Combined Treatments with Photodynamic Therapy for Non-Melanoma Skin Cancer

Non-melanoma skin cancer (NMSC) is the most common form of cancer in the Caucasian population. Among NMSC types, basal cell carcinoma (BCC) has the highest incidence and squamous cell carcinoma (SCC) is less common although it can metastasize, accounting for the majority of NMSC-related deaths. Treatment options for NMSC include both surgical and non-surgical modalities. Even though surgical approaches are most commonly used to treat these lesions, Photodynamic Therapy (PDT) has the advantage of being a non-invasive option, and capable of field treatment, providing optimum cosmetic outcomes. Numerous clinical research studies have shown the efficacy of PDT for treating pre-malignant and malignant NMSC. However, resistant or recurrent tumors appear and sometimes become more aggressive. In this sense, the enhancement of PDT effectiveness by combining it with other therapeutic modalities has become an interesting field in NMSC research. Depending on the characteristics and the type of tumor, PDT can be applied in combination with immunomodulatory (Imiquimod) and chemotherapeutic (5-fluorouracil, methotrexate, diclofenac, or ingenol mebutate) agents, inhibitors of some molecules implicated in the carcinogenic process (COX2 or MAPK), surgical techniques, or even radiotherapy. These new strategies open the way to a wider improvement of the prevention and eradication of skin cancer.

Photodynamic therapy: Progress toward a scientific and clinical network in Latin America

Cancer is one of the major challenges for Latin America health services, since the skin cancer is the most frequent lesion. This manuscript addresses an initiative for the treatment of basal cell carcinomas (BCC) by photodynamic therapy (PDT) based on a government-funded national program in Brazil. The program provides clinical training and facilitates access to drugs/equipment and significantly reduces PDT costs. It also lays foundations for the establishment of a Latin American research network to improve prevention, early detection and treatment of diseases. Centers have been established by direct contact (conferences, visits to healthcare facilities and official departments). A local training was divided into complementary theoretical and practical parts. This is an ongoing project that has involved 10 countries: Brazil, Bolivia Chile, Ecuador, El Salvador, Colombia, Cuba, Mexico, Peru and Venezuela, The initial results are encouraging and have provided assessment of Latin America patients relating, for example, the most common skin phototypes with incidence of BCC in such countries. The network is expected to produce relevant scientific information for PDT introduction in many countries. The experience acquired by local teams shall enable them to innovate PDT protocols and increase the number of skilled contributors/researchers to broaden knowledge on the ever-crescent PDT field in Latin America. The establishment of a collaboration network and introduction of other projects and experience exchange shall become an easier process with time. This PDT clinical research network is a start for the strengthening of Science in South Hemisphere countries.