Treatment Of Nonmelanoma Skin Cancer Research Articles

Translated article] Risk of a Second Skin Cancer in a Cohort of Patients With Nonmelanoma Skin Cancer – Basal Cell Carcinoma or Squamous Cell Carcinoma – Treated With Mohs Micrographic Surgery: A National Prospective Cohort Study

ObjectivePatients with nonmelanoma skin cancer (NMSC)—ie, basal cell carcinoma (BCC) or squamous cell carcinoma (SCC)—have an increased risk of developing a second skin cancer. The aim of this study was to describe the frequency, incidence per 1000 person-years, and predictors of a second skin cancer in a cohort of patients with NMSC treated with Mohs micrographic surgery (MMS). Material and methodsProspective study of a national cohort of patients with NMSC who underwent MMS at 22 Spanish hospitals between July 2013 and February 2020; case data were recorded in the REGESMOHS registry. The study variables included demographic characteristics, frequency and incidence per 1000 person-years of second skin cancers diagnosed during the study period, and risk factors identified using mixed-effects logistic regression. ResultsWe analyzed data for 4768 patients who underwent MMS; 4397 (92%) had BCC and 371 (8%) had SCC. Mean follow-up was 2.4 years. Overall, 1201 patients (25%) developed a second skin cancer during follow-up; 1013 of the tumors were BCCs (21%), 154 were SCCs (3%), and 20 were melanomas (0.4%). The incidence was 107 per 1000 person-years (95% CI, 101–113) for any cancer, 90 per 1000 person-years (95% CI, 85–96) for BCC, 14 (95% CI, 12–16) per 1000 person-years for SCC, and 2 (95% CI, 1–3) per 1000 person-years for melanoma. More men than women developed a subsequent skin cancer (738 [61%] vs 463 [39%]). The main risk factors were a history of multiple tumors before diagnosis (relative risk [RR], 4.6; 95% CI, 2.9–7.1), immunosuppression (RR, 2.1; 95% CI, 1.4–3.1), and male sex (RR, 1.6; 95% CI, 1.4–1.9). ConclusionPatients have an increased risk of developing a second tumor after MMS treatment of NMSC. Risk factors are a history of multiple tumors at diagnosis, immunosuppression, and male sex.

Fluorescence kinetics study of twice laser irradiation based HpD-PDT for nonmelanoma skin cancer.

Hematoporphyrine injection (HpD)-based photodynamic therapy (HpD-PDT) has emerged as a promising cancer therapy. However, its tumor-targeting ability and metabolokinetics in nonmelanoma skin cancer (NMSC) have not been well explored. Importantly, photodynamic diagnosis is widely used for cancer lesion assessment and positioning to ensure effective therapy, while the photosensitizer metabolic kinetics study is utilized for biosafety assessment and light-protection instruction. These are particularly important for the optimization of therapeutic parameters. In the present study, NMSC patients were subjected to twice laser irradiation-based HpD-PDT strategy. Broadly, the study aimed to assess long-term variations in fluorescence (FL) intensity in vivo in NMSC patients after intravenous (i.v.) administration of HpD, and thus obtain information regarding metabolism, biosafety, and light-protection instruction for HpD during the therapy. In vitro experiments were used for the evaluation of absorption and fluorescent characterization of HpD in aqueous solution and cutaneous squamous cell carcinoma (SCC) cells. For in vivo assessment, 20 patients with NMSC, including SCC, basal cell carcinoma (BCC), Bowen disease (BD), extramammary Paget's disease (EMPD), and malignant proliferating tricholemmoma (APT), were recruited, and treated with HpD-PDT. To evaluate the selectivity and pharmacokinetics of HpD in vivo, relative changes in FL intensity for lesional, perilesional, and nonlesional skin of nonmelanoma skin cancer patients, before and after HpD injection, were semiquantitatively analyzed for 1month, using the FL detection system and Wood's lamp. The absorption and FL spectra were detected and semiquantitatively analyzed in HpD diluted solution and SCC cells after coincubation with HpD. After i.v. administration of HpD in EMPD patients, FL was detected in the skin lesions at 24 hours, and it was characterized by clear edges. Importantly, FL intensity in the skin lesions increased significantly at 48and 72hourspostinjection, which was suitable for HpD-PDT. After 72 h, it decreased gradually and reached close to the baseline value at 4 weeks postinjection. No severe side effects were observed during HpD injection and the therapy. Urinary tract infection was recorded in one patient (with a previous history of recurrent urinary tract infections) after HpD-PDT, and the patient was cured afterward. Transient light was observed in two patients after HpD-PDT and they soon recovered after therapy. The present study reported a significant increase in FL intensities at 48and 72hoursafter i.v. administration of HpD in patients with nonmelanoma skin cancers, which indicated accumulation of HpD at the cancer site. Importantly, HpD was found to be safe for NMSC patients. After therapy, FL intensities decreased, which indicated expending and metabolization of HpD. Thus, the results of the present study highlighted the suitability of a twice red-light laser irradiation strategy for the application of HpD-PDT in nonmelanoma skin cancer treatment.

Management of acute, lower extremity surgical wounds using an ablative fractional laser: A single-center, randomized, double-blinded controlled trial

To the Editor: It has been estimated that 5.4 million new cases of nonmelanoma skin cancer are diagnosed each year,1 with up to 10% of basal cell carcinomas and 20% of squamous cell carcinomas occurring on the lower extremities.2 The treatment for nonmelanoma skin cancer is often destructive or surgical, with Mohs micrographic surgery frequently used for skin cancers below the knee. This increase in the incidence of skin cancer on the lower extremities results in an increase in the number of postoperative lower extremity wounds.

Skin cancer in immunosuppressed patients.

The number of people living with chronic immunosuppression is increasing in the United States. Patients with HIV, those who have had bone marrow or solid organ transplants, and patients taking biologics for autoimmune diseases are at increased risk for skin cancer. Skin cancer in these patients is more aggressive and more likely to metastasize and cause death. Medications and individual risk factors such as sex, age, and ethnicity are independent risk factors for the development of skin cancer. Routine screening and aggressive treatment of actinic keratoses and nonmelanoma skin cancers can reduce patients' skin cancer burden and improve patient outcomes.

Riesgo de aparición de segundas neoplasias cutáneas en una cohorte de pacientes diagnosticados de carcinoma queratinocítico (carcinoma basocelular y carcinoma epidermoide) tratados con cirugía de Mohs. Estudio de cohortes prospectivo nacional

ObjectivePatients with nonmelanoma skin cancer (NMSC)—ie, basal cell carcinoma (BCC) or squamous cell carcinoma (SCC)—have an increased risk of developing a second skin cancer. The aim of this study was to describe the frequency, incidence per 1000 person-years, and predictors of a second skin cancer in a cohort of patients with NMSC treated with Mohs micrographic surgery (MMS). Material and methodsProspective study of a national cohort of patients with NMSC who underwent MMS at 22 Spanish hospitals between July 2013 and February 2020; case data were recorded in the REGESMOHS registry. The study variables included demographic characteristics, frequency and incidence per 1000 person-years of second skin cancers diagnosed during the study period, and risk factors identified using mixed-effects logistic regression. ResultsWe analyzed data for 4768 patients who underwent MMS; 4397 (92%) had BCC and 371 (8%) had SCC. Mean follow-up was 2.4 years. Overall, 1201 patients (25%) developed a second skin cancer during follow-up; 1013 of the tumors were BCCs (21%), 154 were SCCs (3%), and 20 were melanomas (0.4%). The incidence was 107 per 1000 person-years (95% CI, 101-113) for any cancer, 90 per 1000 person-years (95% CI, 85-96) for BCC, 14 (95% CI, 12-16) per 1000 person-years for SCC, and 2 (95% CI, 1-3) per 1000 person-years for melanoma. More men than women developed a subsequent skin cancer (738 [61%] vs 463 [39%]). The main risk factors were a history of multiple tumors before diagnosis (relative risk [RR], 4.6; 95% CI, 2.9-7.1), immunosuppression (RR, 2.1; 95% CI, 1.4-3.1), and male sex (RR, 1.6; 95% CI, 1.4-1.9). ConclusionPatients have an increased risk of developing a second tumor after MMS treatment of NMSC. Risk factors are a history of multiple tumors at diagnosis, immunosuppression, and male sex.

Paramedian forehead flap in the treatment of nasal, non-melanoma skin cancer: a cross-sectional study.

nose is the central point of the face and vulnerable to the occurence of non-melanoma skin cancer (NMSC), impacting on appearance. The paramedian forehead flap (PMFF) is considered the best option to treat extensive nasal defects. The objective of this study is to present the experience on PMFF for nasal reconstruction in the treatment of NMSC of a cancer referral center. retrospective study was carried out through data from medical records of patients who underwent nasal reconstruction with PMFF due to NMSC at the Cancer Institute of the State of São Paulo (ICESP). 111 patients were identified, mostly ederly, with comorbidities and on initial tumors (T1 and T2). Basal cell carcinoma (BCC) was the predominant histological type. Dorsum and tip were the most affected subunitis. In addition to skin coverage, reconstruction of the lining and structural framework was also performed in half of the cases. Second intention healing was the technique of choice in closing the donor area. Pedicle division ocurred predominantly in the second operation and the median time to complete reconstruction was 6 months. There were low complication rates. the PMFF is safe and effective to treat nose NMSC, even in cases of high complexity. Since the treatment time can be prolonged and impact on quality of life, it is essential to emphasize and discuss this aspect with the patients before surgery.

High-dose-rate skin brachytherapy with interstitial, surface, or a combination of interstitial and surface mold technique.

PurposeIn order to demonstrate capabilities of brachytherapy in skin cancer treatment, we reviewed clinical outcomes of patients with non-melanoma skin cancer (NMSC) treated with high-dose-rate brachytherapy (HDR-BT) at a single-institution.Material and methodsA surface custom mold (SC), interstitial (IS), or a combination of IS and SC applicator (IS + SC) was used for treatment based on depth of tumor invasion. Contoured growth tumor volume plus a 0.5 cm margin for basal cell carcinomas (BCC) and a 1-1.5 cm margin for squamous cell carcinomas (SCC) was considered a target. A prescription dose of 41.6 Gy in 8 fractions was delivered to BCC, and 46.8 Gy in 9 fractions to SCC.ResultsFrom 2013 to 2018, a total of 751 NMSC patients (534 BCCs and 217 SCCs) were treated with HDR-BT (518 with IS, 225 with SC, and 8 with IS + SC technique). Thirty patients (4%) partially responded to treatment, and 721 patients (96%) had complete responses. Only 3 patients (0.4%) displayed local recurrences. Grade 1, 2, and 3 acute toxicities were observed in 28.0%, 46.7%, and 1.2% of patients, respectively. Grade 1, 2, and 3 late toxicities were observed in 3.3%, 1.3%, and 0.1% of cases. Cosmetic results were excellent in 79.9%, good in 17.8%, fair in 1.7%, and poor in 0.5% of patients.ConclusionsHDR-BT using SC, IS, or IS + SC is an effective treatment for NMSC with good outcomes and cosmetic results in both BCC and SCC.

Preoperative AI-Driven Fluorescence Diagnosis of Non-Melanoma Skin Cancer.

The diagnosis and treatment of non-melanoma skin cancer remain urgent problems. Histological examination of biopsy material—the gold standard of diagnosis—is an invasive procedure that requires a certain amount of time to perform. The ability to detect abnormal cells using fluorescence spectroscopy (FS) has been shown in many studies. This technique is rapidly expanding due to its safety, relative cost-effectiveness, and efficiency. However, skin lesion FS-based diagnosis is challenging due to a number of single overlapping spectra emitted by fluorescent molecules, making it difficult to distinguish changes in the overall spectrum and the molecular basis for it. We applied deep learning (DL) algorithms to quantitatively assess the ability of FS to differentiate between pathologies and normal skin. A total of 137 patients with various forms of primary and recurrent basal cell carcinoma (BCC) were observed by a multispectral laser-based device with a built-in neural network (NN) “DSL-1”. We measured the fluorescence spectra of suspected non-melanoma skin cancers and compared them with “normal” skin spectra. These spectra were input into DL algorithms to determine whether the skin is normal, pigmented normal, benign, or BCC. The preoperative differential AI-driven fluorescence diagnosis method correctly predicted the BCC lesions. We obtained an average sensitivity of 62% and average specificity of 83% in our experiments. Thus, the presented “DSL-1” diagnostic device can be a viable tool for the real-time diagnosis and guidance of non-melanoma skin cancer resection.

Immune Checkpoint Inhibition in Non-Melanoma Skin Cancer: A Review of Current Evidence.

Immuno-oncology is a rapidly evolving field with growing relevance in the treatment of numerous malignancies. The prior study of immunotherapy in dermatologic oncology has largely focused on cutaneous melanoma. However, recent focus has shifted to the use of immunotherapy to treat non-melanoma skin cancers (NMSCs), such as basal cell carcinoma (BCC), cutaneous squamous cell carcinoma (cSCC), and Merkel cell carcinoma (MCC). NMSCs represent the most ubiquitous cancers globally and, while they have a lower propensity to develop into advanced disease than cutaneous melanoma, their absolute mortality burden has recently surpassed that of melanoma. Patients with advanced NMSC are now benefiting from the successes of immunotherapy, including checkpoint inhibition with anti-CTLA-4 and anti-PD-1 monoclonal antibodies. In this review, we discuss the existing clinical evidence for immunotherapy in the treatment of NMSCs, with an emphasis on checkpoint inhibitor therapies. We highlight key studies in the field and provide up-to-date clinical evidence regarding ongoing clinical trials, as well as future study directions. Our review demonstrates that checkpoint inhibitors are positioned to provide unparalleled results in the previously challenging landscape of advanced NMSC treatment.

Effect of plasticizers on drug-in-adhesive patches containing 5-fluorouracil

Topical patches containing 5-fluorouracil (5-FU) are a feasible alternative to overcome the shortcomings of commercial cream for the treatment of non-melanoma skin cancer (NMSC). Plasticizers are a critical component of drug-in-adhesive (DIA) patches as they can significantly affect the mechanical, adhesive and drug release characteristics of the patches. Eudragit® E (EuE) is a methacrylate-based cationic copolymer capable of producing flexible and adhesive films for topical application. In this study, the effect of plasticizers on the mechanical, adhesive and 5-FU release characteristics of EuE-based patches was comprehensively evaluated. While the elongation at break (%) and adhesion of the films were significantly increased with increasing triacetin, dibutyl sebacate (DBS) and triethyl citrate (TEC) concentrations, the tensile strength showed an inverse relationship. EuE plasticized with 40% triacetin, 30% DBS or 40% w/w TEC produced elastic and adhesive films most suitable for topical application. In vitro release studies of the 5-FU-loaded patches demonstrated an initial burst release pattern during the first 10 min followed by a slow release over 120 min. In summary, this study provides important information on effect of plasticizers for preparation of EuE-based patches with desired mechanical, adhesive and release characteristics of 5-FU towards their potential application in the treatment of NMSC.

Non-adherence of surgical treatment in patients with non-melanoma skin cancer: a retrospective cohort pilot study.

There is limited data on non-adherence for surgical treatment in non-melanoma skin cancer (NMSC) patients. The objective of this single-center, retrospective cohort study is to compare rates of non-adherence of surgical treatment options, determine factors associated with non-adherence, and identify barriers for non-adherence. All adult patients with NMSC (> 18years) seen between 2015 and 2017 recommended surgical treatment (surgical excision and electrodessication and curettage (ED&C) or Mohs surgery) were eligible. Non-adherence was defined as not completing recommended treatment and reasons for non-adherence were collected. Out of 427 patients that met inclusion criteria, patients recommended surgical excision and ED&C had a lower non-adherence rate of 3.4% compared to those recommended Mohs (11.4%) (p = 0.006). Factors associated with non-adherence included self-pay patients (19.07% adherent vs. 43.24% non-adherent, p = 0.004). Multivariate logistic regression analysis confirmed that Mohs patients were more likely to be non-adherent (odds ratio (OR) = 3.839, 95% confidence interval (CI) (1.435-10.270), p = 0.007) compared to surgical excision and ED&C patients. Males were more likely to be non-adherent (OR = 2.474, 95% CI (1.105-5.542), p = 0.028) to females, and self-pay patients were more likely to be non-adherent than those with other payers (OR = 3.050, 95% CI (1.437-6.475), p = 0.004). Of the 37 patients who were non-adherent, the most common reasons were loss to follow-up (46%), social reasons (41%), medical reasons (38%), and financial reasons (22%). There was a significant difference in non-adherence rates between surgical treatments for NMSCs in our cohort. Our study suggests the need for future interventional studies that implement strategies and patient education to decrease non-adherence rates.

ПАЦИЕНТОРИЕНТИРОВАННЫЙ АЛГОРИТМ РАБОТЫ РЕНТГЕНОТЕРАПЕВТИЧЕСКОГО КАБИНЕТА ОНКОЛОГИЧЕСКОГО ДИСПАНСЕРА

Results: IIntroduction: Superficial X-ray therapy is a common treatment of non-melanoma skin cancer with a high incidence worldwide. Interrupting the course of radiation therapy can negatively affect patient survival and treatment results. Low treatment adherence may be associated with a lack of a patient-centered approach and ineffective communications. The original study shows that patients undergoing X-ray therapy for cancer may have different needs. Based on the study results an algorithm for a patient-oriented approach has been developed for the X-ray cabinets.
 Purpose: To develop a patient-oriented algorithm of the X-ray therapy room to address the issues of increasing patient satisfaction and forming their adherence to treatment. The objectives of the study included studying and detailing the needs of the patients who passed the X-ray therapy and to develop the patient-oriented algorithm for the X-ray therapy room.
 Material and methods: The study of the patient's values was carried out from 2019 to 2020 by interviewing using open-ended questions to find out the deep motives and beliefs of patients. The study was based on Milton Rokich’s (2005) model of value orientations, which was adapted to the objectives of the study.
 Results: The study included 116 patients undergoing treatment with the X-ray therapy at the City Clinical Oncology Dispensary. As a result of the study, the following patient needs were identified: clinical outcome of the procedure 111 (96 %), safety of treatment and adverse reactions 106 (91 %), cosmetic outcome 53 (46 %), convenience of the treatment schedule 42 (36 %), painlessness of the procedure 39 (34 %), the ability to lead a normal lifestyle 27 (23 %), comfortable conditions for the procedure 16 (14 %), financial costs associated with treatment 10 (9 %), preservation of organ function 4 (3 %). On the basis of the data obtained, a patient-oriented algorithm for the X-ray therapy was developed, including a communication plan with the patient. The study results clearly demonstrate that even with the same disease and condition, patients may have different priorities hat need to be considered to improve patient experience and adherence to treatment.
 Conclusion: Radiation treatment decision-making based on the patients values is important for the development of the patient-centered management in oncology since this directly affects patients’ adherence to treatment. Exploring the values and needs of patients is an opportunity to influence and improve the metrics of the patient experience. Due to the mass incidence of non-melanoma skin cancer, the introduction of patient-centered approaches is an important part of patient satisfaction and increase of patients adherence to the treatment.

Можливості та переваги електронотерапії в лікуванні немеланомного раку шкіри

Проблема захворюваності на немеланомний рак шкіри є актуальною в Україні і в структурі онкологічної захворюваності населення у 2015 році посідала перше місце (10,3 %). Мета роботи: показати сучасні можливості лікування немеланомного раку шкіри електронотерапією з використанням різних енергій електронів. Сучасні лінійні прискорювачі генерують електрони різних енергій — від 4 до 20 МеВ, що дає можливість швидкого зменшення дози з глибиною. Просторовий дозний розподіл випромінювання електронами в тканинах характеризується різною глибиною максимуму дози залежно від обраної енергії — чим вища енергія, тим на більшій глибині розташовується максимум дози. Застосування електронотерапії в режимі опромінення 50 Гр за 10 фракцій є ефективним при лікуванні різних стадій немеланомного раку шкіри. Завдяки вчасно встановленому діагнозу і радикально проведеному лікуванню спостерігається повний регрес пухлинного вогнища без видимих косметологічних дефектів.

Methotrexate in the Treatment of Non-Melanoma Skin Cancers

Background: There are three types of non-melanoma skin cancer (NMSC): basal (BCC), keratoacanathoma (KA), and cutaneous squamous cell carcinoma (cSCC). These three malignancies account for 99 percent of all tumors in this category. Because it slows DNA synthesis in quickly proliferating cells, methotrexate (MTX) is an effective treatment for tumors that are fast developing. To prevent the production of the purine nucleotide thymidine, it inhibits the development of tetrahydrofolate by binding to the dihydrofolate reductase. Objective: To assess the efficacy and safety of MTX in the treatment of NMSCs. Conclusion: When used as a less intrusive and less expensive treatment for NMSCs, MTX has the potential to be a very effective and safe alternative treatment, especially in patients who are elderly or have other medical conditions.

Attitudes among dermatologists regarding non-melanoma skin cancer treatment options

Non-melanoma skin cancers include basal and squamous cell carcinoma. These tumors have become an important health issue for their high incidence and for the morbidity, especially if untreated for a long period. Over the last 20 years, therapeutic approaches for these tumours have been improved and tailored. In this survey we provided data from one hundred and ten Italian dermatologists regarding knowledge and attitude towards different therapeutic approaches on non-melanoma skin cancers. In our study, we observed that surgery and imiquimod 5% cream were the most used treatment by dermatologists for basal cell carcinoma, while, surgery was the most common treatment for cutaneous squamous cell carcinoma. Furthermore, we observed some differences regarding the prescribed therapies in the different Italian geographical areas (i.e., Mohs’ surgery and electrochemotherapy were more frequently used in Northern compared to Central and Southern Italy whereas immunotherapy was more used in Southern compared to Northern and Central Italy) and even considering the year of specialization of the dermatologists (i.e., immunotherapy with cemiplimab was prescribed mainly by dermatologists with 10–19 years of specialization). However, for locally advanced and metastatic forms of basal and squamous cell carcinoma, Hedgehog Pathway Inhibitors and anti- Programmed cell death protein antibody treatment, respectively, were used in line with the newest evolution of therapies regarding this topic. Considering the importance of skin cancers and its progressive increase in incidence, it is crucial to improve the knowledge of different therapeutic approaches among dermatologists.

1095TiP Daromun, a dermato-oncology drug in development for stage III and IV melanoma and non-melanoma skin cancers: A clinical overview

Daromun (Nidlegy®) is an immuno-oncology drug in clinical development for the treatment of melanoma and non-melanoma skin cancers (NMSC). The product, which is administered intralesionally, consists of two antibody-cytokine fusions as active principles (L19IL2 and L19TNF), which act synergistically to directly kill tumor cells while also inducing a systemic anti-tumor immune response. The drug is the first oncology product to receive EMA’s agreement for development as combination pack. Daromun is being investigated in two phase III studies in the neoadjuvant setting for fully resectable, locally advanced melanoma in EU and in the US.

LB794 Synthesis and biological evaluation of a small molecule library identifies novel anti-skin cancer agents

Treatment of melanoma (MSC) and non-melanoma skin cancers (NMSCs, basal cell carcinoma (BCC), and squamous cell carcinoma (SCC)), affecting one-fifth of the US population, is hampered by drug resistance, side effects, and low bioavailability. Owing to low molecular weight and the ability to enter cells, small molecules are gaining ground towards enhancing bioavailability and minimizing some of the side effects associated with classical cancer drugs. Herein, we synthesized a mini-library of 86 compounds via C-N/C-C coupling, direct substitution on the aromatic ring, or a modified Skraup–Doebner–von Miller approach, and their solubility and biological properties were characterized.

Concordance between a Mohs surgeon and a dermatopathologist in evaluating Mohs cryosections.

Mohs micrographic surgery is the gold standard treatment for high-risk non-melanoma skin cancers. The success of Mohs relies on accurate histopathologic evaluation. Due to law restrictions in some European countries, Mohs surgeons are not permitted to report on histopathology; therefore, a pathologist evaluates the frozen sections. To retrospectively assess the concordance between the certified Mohs surgeon and the pathologist in evaluating the Mohs slides that were intraoperatively evaluated by the pathologist. Frozen section slides of a total of 237 Mohs cases between 2013 and 2020 were examined by the blinded Mohs surgeon, and the tumours were marked on copy maps. The copy maps and the original maps were compared, and the non-concordant cases were re-evaluated together by the Mohs surgeon and the dermatopathologist. The concordance rate was calculated, and the inter-rater agreement was statistically analysed using Cohen's Kappa coefficient. We report a high concordance rate (97.9%) and inter-rater agreement (0.96) between Mohs surgeon and dermatopathologist in evaluating Mohs slides. As a newly settled centre, our results are in alignment with experienced centres where the Mohs surgeon evaluates the slides herself and performs the surgery.

Dermabrasion combined with photodynamic therapy: a new option for the treatment of non-melanoma skin cancer.

Non-melanoma skin cancer (NMSC) is the most common malignancy. Photodynamic therapy (PDT) is effective for the treatment of certain NMSCs. However, the clinical response rates of some NMSCs to single PDT are still far from ideal. The reason may be that PDT has shown limited efficacy in managing thicker NMSCs. To explore the efficacy and safety of dermabrasion combined with PDT (D-PDT) for the treatment of NMSCs. This was a retrospective, single-arm, multi-centre study. In total, 172 tumours from 40 patients were treated with D-PDT during the study period. The mean follow-up period was 40months (range 15-110months). D-PDT was performed with 633-nm red light at 80mW/cm2 after lesion dermabrasion and 4h of photosensitizer exposure. Six nodular basal cell carcinomas (nBCCs) from 6 patients, 9 squamous cell carcinomas (SCCs) from 9 patients, 17 Bowen diseases (BDs) from 10 patients and 140 actinic keratoses (AKs) from 15 patients treated with D-PDT were examined in this study. Only two patients with three AKs experienced recurrence over 12months. The mean final follow-up periods of patients with AKs, BDs, nBCCs and SCCs were 30, 33, 45 and 60months, respectively. Thirty-four of the 40 patients treated with D-PDT reported excellent or good cosmetic results. The mean Dermatology Life Quality Index (DLQI) scores of the patients improved significantly after treatment (estimated MD 9.72 [95% CI 8.69 to 10.75]; p < 0.001). D-PDT is a safe, cosmetic and effective treatment that could be a new candidate therapeutic for NMSC.

25686 Variability in the dosing of PD1 inhibitors used for treatment of nonmelanoma skin cancers

Nonmelanoma skin cancer (NMSC) represents the most common cancer diagnosed in the United States. These tumors are frequently treated by surgical modalities. Patients with advanced disease require a different approach to therapy. Programmed cell death protein 1 (PD1) inhibitors are an emerging immunotherapeutic option for the treatment of a variety of tumors including advanced NMSC. Cemiplimab is a PD-1 inhibitor approved for treatment of locally advanced or metastatic cutaneous squamous cell carcinoma (cSCC) not amenable to curative surgery or radiation. Pembrolizumab and nivolumab are PD1 inhibitors used as off-label therapies for advanced cSCC or basal cell carcinoma (BCC). We conducted a PubMed literature search up to August 8, 2020 to include studies on the use of PD-1 inhibitors in patients with advanced NMSC. Thirty-seven articles reported a total of 432 unique cases of advanced cSCC or BCC treated with PD1 inhibitors. The most common dosing schedules for pembrolizumab (2 mg/kg q3 weeks), nivolumab (3 mg/kg q2 weeks), or cemiplimab (3 mg/kg q2 weeks) were identified. A total of 10 different dosing schedules were identified. Outcomes of these patients ranged between progressive disease to achievement of a complete clinical response. All 3 PD1 inhibitors showed adequate safety profiles with few reported adverse events that were grade 3 or above. The use of cemiplimab, pembrolizumab, and nivolumab for advanced NMSC has shown promising results. However, the literature shows a wide range of dosing regimens for these therapies. Further studies are needed to guide clinicians toward the optimal dosage and the ideal anti-PD1 agent for their patients.