Current Role of Radiotherapy in Non-melanoma Skin Cancer

Outcomes With Radiation Therapy as Primary Treatment for Unresectable Cutaneous Head and Neck Squamous Cell Carcinoma

AIMS

Unresectable cutaneous squamous cell cancer of the head and neck (HNcSCC) poses treatment challenges in elderly and comorbid patients. Radiation therapy (RT) is often employed for locoregional control. This study aimed to determine progression-free survival (PFS) and overall survival (OS) outcomes achieved with upfront RT in unresectable HNcSCC. It also aimed to determine the impact of varying RT dose regimes on disease outcomes.

METHODS

A retrospective cohort study was conducted of patients with unresectable HNcSCC treated with first-line RT at a tertiary teaching hospital in Sydney, Australia between 2015-2024. Patient, disease, treatment and follow-up data were extracted from the electronic records.

RESULTS

Of 36 patients, 67% were male, median age was 81 years, and median Charlson Comorbidity Index was 6.5. Median follow-up was 21 months. 83% of RT courses were delivered via intensity-modulated radiation therapy (IMRT) or volumetric-modulated arc therapy (VMAT). Objective response rate was 97%. Patients were grouped into low-dose RT receiving biologically equivalent dose (BED) <60Gy (n = 18) or high-dose RT (BED ≥ 60Gy, n = 18). Infield progression-free survival (PFS) at 6 months was 56% and 78%, respectively. Overall survival at 6 months was 83% and 89%, and by 24 months 31% and 65%, respectively.

CONCLUSION

RT is an efficacious treatment that can be tailored to individual patient contexts with unresectable HNcSCC. It has a high response rate overall, with higher doses producing longer disease control. Some patients with poorer functional status receiving low-dose RT can still achieve a sustained response. Future comparisons of outcomes and cost-effectiveness with emerging treatments such as immunotherapy will be important in guiding management for frail patients with unresectable disease.

Squamous Cell Carcinomas in Horses: An Update of the Aetiopathogenesis and Treatment Options

Squamous cell carcinomas are a very common tumor type in horses, and are found in a variety of dermatologic and non-dermatologic locations. Metastasis is common, even at the first presentation of the disease, and a full staging workup is therefore strongly recommended to direct treatment and assist with prognostication. Wide surgical excision remains the treatment of choice in most cases, but recurrence is common, and adjunctive therapy may be indicated to improve the long-term prognosis.

Image Guidance is Associated with Improved Freedom From Recurrence After Superficial Radiation Therapy for Nonmelanoma Skin Cancer

Purpose

This is the first study to quantify the 2-year freedom from recurrence for individuals with nonmelanoma skin cancer (NMSC) such as basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and squamous carcinoma in situ (SCCIS) treated with image guided superficial radiation therapy (IGSRT) versus SRT without image guidance.

Methods and Materials

This retrospective cohort study evaluates the 2-year freedom recurrence rate of NMSCs treated by IGSRT (March 2016 to January 2022) and compares it to existing data on NMSCs treated by SRT via 1 sample proportion tests. Individuals >18 years old with biopsy-proven SCC, SCCIS, and/or BCC treated with IGSRT were included in the study, and 1602 patients/2880 treated lesions were followed until January 14, 2022. SRT literature was identified through an Ovid Medline search.

Results

All NMSCs treated by IGSRT in this cohort had an aggregate 2-year freedom from recurrence of 99.23%. The recurrence rate for BCC (N = 1382) was 1.1%, for SCC (N = 904) 0.8%, and for SCCIS (N = 594) 0.0%. These recurrence rates are significantly improved compared with a pooled study that evaluated NMSCs across histology and BCCs alone treated without image guidance (standard SRT) (P < .001).

Conclusions

IGSRT offers a paradigm-shifting treatment option for patients with NMSCs - offering statistically significantly improved outcomes compared with standard SRT and a more desirable toxicity profile to surgical options. This study demonstrates that IGSRT is associated with remarkably low recurrence rates, which are statistically significantly improved from the previous generation of SRT and in line with modern outcomes for Mohs micrographic surgery.

Assessment of educational services by Patient Target Group participating in the National Skin Cancer Prevention Programme (OPPNS) based on the example of the Wielkopolska region

Background

Skin melanoma is one of the three main types of skin cancer along with basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), and develops from melanocytes. 2019 saw the beginning of the National Skin Cancer Prevention Programme (OPPNS) in Poland. One of the tasks performed was a health promotion campaign for patients. To effectively educate the public, the project was preceded by a survey assessing knowledge on skin cancer prevention methods. Then, the survey was repeated to evaluate the effectiveness of the awareness raising campaign.

Materials and methods

both studies were conducted based on an author-developed survey. A representative sample size was determined based on the calculator available at www.cem.pl/pl/analizy/wielkość-proby. In addition, each participant filled in a knowledge upgrade declaration. The analysis employed basic statistical data, such as absolute numbers and structural indicators.

Results and Conclusions

Knowledge upgrade score of 9.16 (out of 10) was declared by 99.7% of the respondents. As many as 99.0% of them declared an intent to change their lifestyle to a healthier one. Thus, the education provided to the Programme participants was confirmed to have raised their awareness of skin cancer prevention and self-examination methods.

A study of polarity effect for various ionization chambers in kilovoltage x-ray beams

BACKGROUND

Ionization chambers play an essential role in dosimetry measurements for kilovoltage (kV) x-ray beams. Despite their widespread use, there is limited data on the absolute values for the polarity correction factors across a range of commonly employed ionization chambers.

PURPOSE

This study aimed to investigate the polarity effects for five different ionization chambers in kV x-ray beams.

METHODS

Two plane-parallel chambers being the Advanced Markus and Roos and three cylindrical chambers; 3D PinPoint, Semiflex and Farmer chamber (PTW, Freiburg, Germany), were employed to measure the polarity correction factors. The kV x-ray beams were produced from an Xstrahl 300 unit (Xstrahl Ltd., UK). All measurements were acquired at 2 cm depth in a PTW-MP1 water tank for beams between 60 kVp (HVL 1.29 mm Al) and 300 kVp (HVL 3.08 mm Cu), and field sizes of 2-10 cm diameter for 30 cm focus-source distance (FSD) and 4 × 4 cm2 - 20 × 20 cm2 for 50 cm FSD. The ionization chambers were connected to a PTW-UNIDOS electrometer, and the polarity effect was determined using the AAPM TG-61 code of practice methodology.

RESULTS

The study revealed significant polarity effects in ionization chambers, especially in those with smaller volumes. For the plane-parallel chambers, the Advanced Markus chamber exhibited a maximum polarity effect of 2.5%, whereas the Roos chamber showed 0.3% at 150 KVp with the 10 cm circular diameter open-ended applicator. Among the cylindrical chambers at the same beam energy and applicator, the Pinpoint chamber exhibited a 3% polarity effect, followed by Semiflex with 1.7%, and Farmer with 0.4%. However, as the beam energy increased to 300 kVp, the polarity effect significantly increased reaching 8.5% for the Advanced Markus chamber and 13.5% for the PinPoint chamber at a 20 × 20 cm2 field size. Notably, the magnitude of the polarity effect increased with both the field size and beam energy, and was significantly influenced by the size of the chamber's sensitive volume.

CONCLUSIONS

The findings demonstrate that ionization chambers can exhibit substantial polarity effects in kV x-ray beams, particularly for those chambers with smaller volumes. Therefore, it is important to account for polarity corrections when conducting relative dose measurements in kV x-ray beams to enhance the dosimetry accuracy and improve patient dose calculations.

Defect Engineering in Biomedical Sciences

With the promotion of nanochemistry research, large numbers of nanomaterials have been applied in vivo to produce desirable cytotoxic substances in response to endogenous or exogenous stimuli for achieving disease-specific therapy. However, the performance of nanomaterials is a critical issue that is difficult to improve and optimize under biological conditions. Defect-engineered nanoparticles have become the most researched hot materials in biomedical applications recently due to their excellent physicochemical properties, such as optical properties and redox reaction capabilities. Importantly, the properties of nanomaterials can be easily adjusted by regulating the type and concentration of defects in the nanoparticles without requiring other complex designs. Therefore, this tutorial review focuses on biomedical defect engineering and briefly discusses defect classification, introduction strategies, and characterization techniques. Several representative defective nanomaterials are especially discussed in order to reveal the relationship between defects and properties. A series of disease treatment strategies based on defective engineered nanomaterials are summarized. By summarizing the design and application of defective engineered nanomaterials, a simple but effective methodology is provided for researchers to design and improve the therapeutic effects of nanomaterial-based therapeutic platforms from a materials science perspective.

Robot-Assisted Nasal Reconstruction: A Cadaveric Study

OBJECTIVE

Manual contouring of cartilage for nasal reconstruction is tedious and time-consuming. The use of a robot could improve the speed and precision of the contouring process. This cadaveric study evaluates the efficiency and accuracy of a robot methodology for contouring the lower lateral cartilage of the nasal tip.

METHODS

An augmented robot with a spherical burring tool attached was utilized to carve 11 cadaveric rib cartilage specimens. In phase 1, the right lower lateral cartilage was harvested from a cadaveric specimen and used to define a carving path for each rib specimen. In phase 2, the cartilage remained in situ during the scanning and 3-dimensional modeling. The final carved specimens were compared with the preoperative plans through topographical accuracy analysis. The contouring times of the specimens were compared with 14 retrospectively reviewed cases (2017-2020) by an experienced surgeon.

RESULTS

Phase 1 root mean square error of 0.40±0.15 mm and mean absolute deviation of 0.33±0.13 mm. Phase 2 root mean square error of 0.43 mm and mean absolute deviation of 0.28 mm. The average carving time for the robot specimens was 14±3 minutes and 16 minutes for Phase 1 and Phase 2, respectively. The average manual carving by an experienced surgeon was 22±4 minutes.

CONCLUSIONS

Robot-assisted nasal reconstruction is very precise and more efficient than manual contouring. This technique represents an exciting and innovative alternative for complex nasal reconstruction.

Hypofractionated radiotherapy for invasive squamous cell carcinoma of the scalp in the elderly: Efficacy and tolerance, preliminary results

PURPOSE

Skin squamous cells carcinomas (SCC) are frequently tumor, especially in the elderly population. Surgical excision is the standard treatment. But for patients suffering large tumor or/with comorbidity, a conservative approach with irradiation can be proposed. The hypofractionated schedule is used to shorten the overall treatment time with same results and without compromising therapeutic outcomes. The aim of this study is to assess the efficacy and tolerance of hypofractionated radiotherapy for invasive SCC of the scalp in elderly.

PATIENTS AND METHODS

We included patients suffering from SCC of the scalp and treated by hypofractionated radiotherapy at the Institut de cancérologie de Lorraine or centre Émile-Durkeim d'Épinal, from January 2019 to December 2021. Characteristics of patients, size of the lesion and side effects were collected retrospectively. Tumor size at 6 months corresponded to the primary endpoint. Toxicity was collected for the secondary endpoint.

RESULTS

Twelve patients with a median age of 85 years old were included. The mean size was 4,5cm with a bone invasion in 2/3 of cases. Radiotherapy was delivered after surgical excision for half of the patient. The dose delivered was 54Gy in 18 daily fractions size. Six months after irradiation: 6/11 patients had no residual lesion, 2/11 had a partial response with a residual lesion of about 1cm. 3 patients presented local recurrence. One patient died within 6 months of radiotherapy because of another comorbidity. In total, 25% had presented a grade 3 acute radiation dermatitis, no grade 4 toxicity.

CONCLUSION

Short term of moderately hypofractionated schedule radiotherapy was a success with complete or partial response for more than 70% of the patients in squamous cell carcinomas. There is no major side effect.

The Role of Radiation Therapy in the Treatment of Non-Melanoma Skin Cancer

Non-melanoma skin cancer (NMSC) is the most common malignancy in the United States. While surgery is considered as the main treatment modality for both cutaneous basal cell carcinoma (cBCC) and cutaneous squamous cell carcinoma (cSCC), radiotherapy plays an important role in the treatment of NMSC, both in the adjuvant setting for cases considered high-risk for recurrence, and in the definitive setting, when surgery is not feasible or desired by the patient. The last years have seen the emergence of immunotherapy treatment for cases of advanced cSCC in the palliative, and possibly neoadjuvant settings, making the treatment paradigm more complex. In this review, we attempt to describe the different radiation modalities available for the treatment of NMSC, the indications for adjuvant post-operative treatment with radiotherapy for cSCC, the role of radiotherapy in elective neck treatment, and the efficacy, safety, and toxicity profile of this treatment in these different settings. Furthermore, we aim to describe the efficacy of radiotherapy combined with immunotherapy as a promising horizon for treating advanced cSCC. We also aim to describe the ongoing clinical studies that attempt to examine future directions for the role of radiation treatment in NMSC.

Recommendations of the International Society of Geriatric Oncology on skin cancer management in older patients

INTRODUCTION

Non-melanoma skin cancer (NMSC) is becoming ever more prevalent among older adults. However, older adults with NMSC are often underrepresented in clinical trials and guidelines on effective management is still unclear. The International Society of Geriatric Oncology (SIOG) created a multi-disciplinary task force to explore the potential in developing practical guidelines for the treatment of older patients with basal cell carcinoma (BCC) and skin (cutaneous) squamous cell carcinoma (cSCC).

MATERIALS AND METHODS

A systematic literature search to identify relevant and up-to-date literature on treatment of NMSC in older adults was conducted on various databases including MEDLINE, Embase, CINAHL, Cochrane, and PubMed. The resulting papers were discussed by an expert panel, leading to a consensus recommendation.

RESULTS

A total of 154 articles were identified for the expert panel to utilise in generating consensus recommendations. A major focus on geriatric assessment and management options including surgery, radiotherapy, systemic therapy, clinical monitoring, and medical/medicophysical therapy were reviewed for recommendations.

DISCUSSION

Patient age should not be the sole deciding factor in the management of patients with NMSC. Assessment from a multidisciplinary team (MDT) is crucial, and the decision-making process should consider the patient's lifestyle, needs, and expectations. A comprehensive geriatric assessment should also be considered. Patients should feel empowered to advocate for themselves and have their views considered a part of the MDT discussion.

Non-melanoma skin cancer of the head and neck

Skin cancer is the most common malignancy in the world, and the majority of cases affect the skin of the head and neck. The face is a particularly emotive area for patients who often present with a lesion that is causing them concern. This article reviews the identification, diagnosis and principles of management of non-melanoma skin cancer of the head and neck. There are many lesions of the skin which are benign and mimic skin cancer. The differential of head and neck skin lesions and how to determine their nature is discussed. The vast majority of non-melanoma skin cancer are basal cell carcinoma, followed by squamous cell carcinoma. These and the other types of non-melanoma skin cancer are described and illustrated. Current methods of clinical identification, diagnosis and evaluation of skin cancers are clarified, and contemporary treatment paradigms are presented.

The current understanding of the immune landscape relative to radiotherapy across tumor types

Radiotherapy is part of the standard of care treatment for a great majority of cancer patients. As a result of radiation, both tumor cells and the environment around them are affected directly by radiation, which mainly primes but also might limit the immune response. Multiple immune factors play a role in cancer progression and response to radiotherapy, including the immune tumor microenvironment and systemic immunity referred to as the immune landscape. A heterogeneous tumor microenvironment and the varying patient characteristics complicate the dynamic relationship between radiotherapy and this immune landscape. In this review, we will present the current overview of the immunological landscape in relation to radiotherapy in order to provide insight and encourage research to further improve cancer treatment. An investigation into the impact of radiation therapy on the immune landscape showed in several cancers a common pattern of immunological responses after radiation. Radiation leads to an upsurge in infiltrating T lymphocytes and the expression of programmed death ligand 1 (PD-L1) which can hint at a benefit for the patient when combined with immunotherapy. In spite of this, lymphopenia in the tumor microenvironment of 'cold' tumors or caused by radiation is considered to be an important obstacle to the patient's survival. In several cancers, a rise in the immunosuppressive populations is seen after radiation, mainly pro-tumoral M2 macrophages and myeloid-derived suppressor cells (MDSCs). As a final point, we will highlight how the radiation parameters themselves can influence the immune system and, therefore, be exploited to the advantage of the patient.

Customized 3D-printed molds for high dose-rate brachytherapy in facial skin cancer: First clinical experience

BACKGROUND AND OBJECTIVE

Radiotherapy of elderly, frail patients with facial skin cancer in proximity to critical organs is challenging. This is the first report on clinical experience with facial skin cancer treated by individualized 3D-printer-based mold high-dose-rate (HDR) brachytherapy (BT).

PATIENTS AND METHODS

Fifteen patients not eligible for radical surgery or definitive external beam radiotherapy (EBRT) were treated with 3D-printer-based mold HDR-BT. Patient selection and treatment were in accordance with multidisciplinary tumor board recommendations. Clinical response, toxicity and cosmesis were analyzed.

RESULTS

Median age was 77 years. Histology revealed squamous cell carcinoma in seven, basal cell carcinoma in five, melanoma in situ in one, Lentigo maligna in one, and melanoma in one patient, respectively. Median prescription dose was 39 Gy delivered in once-daily fractions of 3 Gy. After a median follow-up of 12.2 months, local recurrence was observed in one patient with melanoma in situ. Apart from one grade 4 cataract, no other > grade 2 late toxicity was documented.

CONCLUSIONS

HDR-BT with 3D-printer-based molds for facial skin cancer is a well-tolerated and safe treatment option for elderly, frail patients not eligible for radical surgery or definitive EBRT due to functional inoperability or tumor location.

Skin cancer in solid organ transplant recipients: still an open problem

In the last two decades, the optimization of organ preservation and surgical techniques, and the personalized immunosuppression have reduced the rate of acute rejections and early post-transplant complications. However, long-term graft survival rates have not improved over time, and evidence suggest a role of chronic calcineurin inhibitor toxicity in this failure. Solid organ transplant recipients may develop chronic dysfunction/damage and several comorbidities, including post-transplant malignancies. Skin cancers, mostly non-melanoma skin cancers (squamous cell carcinoma and basal cell carcinoma), are the most common malignancies in Caucasian solid organ transplant recipients. Several factors, together with immunosuppression, may contribute to the susceptibility for skin cancers which, although often treatable, could be associated with a much higher mortality rate than in the general population. The rapid identification and treatment (including reduction of immunosuppression and early surgical treatments) have an important role to avoid an aggressive behavior of these malignancies. Organ transplant recipients with a history of skin cancer should be followed closely for developing new and metastatic lesions. Additionally, patient education on the daily use of sun-protective measures and the recognition of the early signs (self-diagnosis) of coetaneous malignancies are useful preventive measures. Finally, clinicians should make themselves aware of the problem and build, in every clinical follow-up center, collaborative network involving transplant clinicians, dermatologists and surgeons who should work together to easily identify and rapidly treat these complications. In this review, we discuss the current literature regarding the epidemiology, risk factors, diagnosis, preventive strategies and treatments of skin cancer in organ transplantation.

Validation of an individualized home-made superficial brachytherapy mold applied for deep nonmelanoma skin cancer

Background

This study was conducted to evaluate the effect of brachytherapy (BT) customized mold [Condensation silicone elastomer (Protesil^TM)] and its thickness on the dose distribution pattern of deep nonmelanoma skin cancers (NMSC).

Materials and methods

Four blocks of mold material were constructed in 5, 10, 15, and 20 mm thickness and 100 × 100 mm² area by a plastic cast. The high dose rate (HDR) plus treatment planning system (TPS) (Version 3, Eckert & Ziegler BEBIG Gmbh, Berlin, Germany) with a ⁶⁰Co source (model: Co0.A86, EZAG BEBIG, Berlin, Germany) as an high dose rate brachytherapy (HDR-BT) source was used. Solid phantom and MOSFET^TM and GAFCHROMIC^TM EBT3 film dosimeters were used for experimental dosimetry of the different thicknesses (up to 20 mm) of BT customized mold. Skin dose and dose to different depths were evaluated.

Result

The TPS overestimated the calculated dose to the surface. Skin dose can be reduced from 250% to 150% of the prescription dose by increasing mold thickness from 5 mm to 20 mm. There was a 7.7% difference in the calculated dose by TPS and the measured dose by MOSFET. There was a good agreement between film dosimetry, MOSFET detector, and TPS' results in depths less than 5 mm.

Conclusion

Each BT department should validate any individualized material chosen to construct the customized surface BT mold. Increasing the mold thickness can treat lesions without overexposing the skin surface. Superficial BT can be recommended as an appropriate treatment option for some deep NMSC lesions (up to 20 mm) with pre-planning considerations employing thicker molds.

Laminated holmium-166-containing electrospun bandages for use against skin cancer

The number of non-melanoma skin cancer (NMSC) cases in the US will increase significantly over the next decade due to a rise in UV exposure. One of the treatment methods used to remove NMSC lesions is radiation therapy. The two types of radiation therapy used in the clinic are external beam therapy and brachytherapy. However, both require specialized on-site instrumentation and for patients to remain immobile. In this work, we studied an alternative radiation therapy - one that does not require expensive on-site equipment and would allow for enhanced patient mobility and, thus, comfort. We prepared sealed source, nylon-laminated holmium-166-containing radiotherapeutic bandages and used them in C3H/HeN mice with murine SCCVII tumor grafts. Overall, tumor sizes were smallest when treated with therapeutically relevant radiation doses via radiotherapeutic bandages (compared to controls), and no histological evidence of toxicity to tissues was observed. Thus, our optimized radiotherapeutic bandage offers a flexible approach to treating NMSC.

H&N and Skin (HNS) GEC-ESTRO Working Group critical review of recommendations regarding prescription depth, bolus thickness and maximum dose in skin superficial brachytherapy with flaps and customized moulds

The aim of this publication is the assessment of the existing guidelines for non-melanoma skin cancer (NMSC) superficial brachytherapy (BT) and make a critical review based on the existing literature about the maximum dose prescription depth, bolus thickness and maximum skin surface dose (D_max) of the published clinical practice. A systematic review of NMSC superficial BT published articles was carried out by the GEC-ESTRO Head & Neck and Skin (HNS) Working Group (WG). 10 members and 2 external reviewers compared the published clinical procedures with the recommendations in the current guidelines and examined the grade of evidence. Our review verified that there is a large variation among centres with regards to clinical practice in superficial BT and identified studies where published parameters such as maximum dose prescription depth, bolus thickness and D_max exceed the constraints recommended in the guidelines, while showing excellent results in terms of local control, toxicity and cosmesis. This review confirmed that current recommendations on skin superficial BT do not include published experience on tumours treated with superficial BT that require dose prescription depth beyond the recommended 5mm under the skin surface and that the existing literature does not provide sufficient evidence to relate dosimetry of superficial BT to patient reported outcome measures. The GEC-ESTRO HNS WG considers acceptable to prescribe superficial BT dose at a depth above 5mm beyond the skin surface, and modify the bolus thickness to optimize the treatment plan and adjust the acceptable maximum dose on the skin surface, all pending clinical situation.

Characteristics and management of skin cancers in very elderly patients: A real-world challenge for clinicians

The increase life expectancy led to an expected increase in skin cancer incidence in older patients. Their treatment can require a complex decision-making process. Limited data are available on characteristics, management and outcome of skin tumours in nonagenarian and centenarian patients. The aim of our study was to describe epidemiology, clinical-pathological features and treatment strategies of skin cancers in a cohort of patients aged ≧95 years. A total of 116 patients ≧95 years of age presented for the evaluation of 225 skin lesions (mean of 1.94 lesions per patient). The mean age was 97.4 years, 57.8% were women. Most patients had an ECOG score of 3 (49.3%) or 4 (32%). Lesions were mainly located on the head and neck area (74.2%), upper (7.1%) and lower (6,2%) limbs. The majority of patients presented with non-melanoma skin cancers (183/225; 81.3%), 25/225 (11.1%) had actinic keratosis, 5 (2.2%) melanoma and 2 (0.9%) atypical fibroxanthoma. Forty-eight lesions (21.3%) were treated with surgery, 58 (25.8%) with radiotherapy. The management of 73 lesion (32.4%) was discussed at the multidisciplinary tumour board meeting. One patient died for the progression of a squamous cell carcinoma; 74 patients died for causes unrelated to skin tumours, 36 are still alive after a mean follow-up of 27.27 months. This cohort study confirms that age is not per se a contraindication for treatment of skin cancers in elderly patients. Our results support the importance of a patient-centred care approach that should take into consideration patient's preferences, comorbidities, compliance and possible adverse events.

Fiber-Optic Based Laser Wakefield Accelerated Electron Beams and Potential Applications in Radiotherapy Cancer Treatments

Ultra-compact electron beam technology based on laser wakefield acceleration (LWFA) could have a significant impact on radiotherapy treatments. Recent developments in LWFA high-density regime (HD-LWFA) and low-intensity fiber optically transmitted laser beams could allow for cancer treatments with electron beams from a miniature electronic source. Moreover, an electron beam emitted from a tip of a fiber optic channel could lead to new endoscopy-based radiotherapy, which is not currently available. Low-energy (10 keV–1 MeV) LWFA electron beams can be produced by irradiating high-density nano-materials with a low-intensity laser in the range of ~1014 W/cm2. This energy range could be useful in radiotherapy and, specifically, brachytherapy for treating superficial, interstitial, intravascular, and intracavitary tumors. Furthermore, it could unveil the next generation of high-dose-rate brachytherapy systems that are not dependent on radioactive sources, do not require specially designed radiation-shielded rooms for treatment, could be portable, could provide a selection of treatment energies, and would significantly reduce operating costs to a radiation oncology clinic.

Radiotherapy in the Adjuvant and Advanced Setting of CSCC

Introduction

The use of radiotherapy for cutaneous squamous cell carcinoma (CSCC) has solid historical roots. It is used with patients who are not suitable for surgery, with patients with high-risk histological features in the adjuvant setting, and in palliative care.

Objectives

The aim of this article is to summarize and provide a radiation therapy overview on the indications, effectiveness, and potential adverse events of radiotherapy in the adjuvant and advanced setting of CSCC.

Methods

We performed a comprehensive literature review on PubMed, adopted as our biomedical literature database. Articles were selected based on their date of publication (in the last 30 years) and relevance.

Results

Radiotherapy (RT) can safely be used to manage non-surgical patients and high-risk patients in the advanced CSCC setting. The remarkable progress of delivery techniques has greatly improved the effectiveness and toxicity profile of RT treatments. From 2D techniques to intensity modulated radiation therapy (IMRT), and brachytherapy, all RT techniques have greatly advanced. To improve acute and chronic side effects, a deeper care has been used. As regards CSCC, several dose fractionations and schedules have been suggested, in line with the patient's age and medical conditions.

Conclusions

RT is a fundamental and constantly evolving therapeutic option in the treatment of CSCC, to minimize the risk of recurrence and metastases in the adjuvant setting and in the exclusive treatment for non-surgical patients. Patients' selection is crucial, together with and a collaborative team working approach among the specialists involved in disease management in the perspective of the best multidisciplinary assessment.

Hide-and-seek: Neurotropic squamous cell carcinoma of the periorbital region - a series of five cases and review of the literature

Squamous cell carcinoma is the second most common malignancy of the skin after basal cell carcinoma and mainly found in sun‐exposed areas such as the face. This mostly locally destructive malignancy may show invasive growth and insidious mechanisms of dissemination such as perineural invasion. Periorbital squamous cell carcinoma is associated with perineural invasion in up to 14 % of cases. Specifically in this region, the proximity to cranial nerves and therefore the associated risk of progression to the central nervous system are associated with poor prognosis. The clinically concealed character of this entity often leads to a delay in diagnosis and consequently makes complete resection and reconstruction demanding. Careful clinical evaluation often hints at perineural invasion before obtaining histology.

Aside from presenting five challenging cases, this work analyzes risk factors, clinical as well as histological features, and treatment options for periorbital squamous cell carcinoma with perineural invasion.

Hide-and-seek: Neurotropes Plattenepithelkarzinom der periorbitalen Region - eine Fallserie und Übersichtsarbeit aktueller Literatur

Das Plattenepithelkarzinom ist nach dem Basalzellkarzinom das zweithäufigste Malignom der Haut und wird vorwiegend an sonnenexponierten Stellen wie der Gesichtshaut diagnostiziert. Diese meist lokal destruktiv wachsende Malignität kann durchaus auch invasives Wachstumsverhalten, wie perineurale Ausbreitungsmechanismen, aufweisen. Das Plattenepithelkarzinom der periorbitalen Region ist in bis zu 14 % der Fälle mit perineuraler Invasion assoziiert. Vor allem in diesem Bereich birgt die anatomische Nähe zu den Hirnnerven das Risiko einer Progression Richtung zentrales Nervensystem, was mit einer schlechteren Prognose assoziiert ist. Der klinisch unauffällige Charakter dieser Entität resultiert oft in einer Verzögerung der definitiven Diagnosestellung, wodurch die vollständige Resektion und anschließende Rekonstruktion erschwert werden. Eine aufmerksame klinische Evaluierung kann bereits vor Erlangen histologischer Befunde Hinweise für ein perineurales Wachstum liefern. Neben fünf herausfordernden Fällen analysiert diese Arbeit Risikofaktoren, klinische als auch histologische Merkmale und Behandlungsoptionen des periorbitalen Plattenepithelkarzinoms mit perineuraler Invasion.

Stereotactic body radiotherapy for head and neck skin cancer

AIM

To report outcomes of Stereotactic Body Radiotherapy (SBRT) for head and neck skin cancer (HNSC) patients treated at a high-volume center.

MATERIALS

A retrospective review of HNSC SBRT patients from 2012 to 2019 was conducted. Kaplan-Meier method was used to estimate local control (LC), locoregional control (LRC) outside of SBRT field, overall survival (OS), progression-free survival (PFS) and late toxicity (LT). Univariate and multivariate analyses were performed. Grade 3-4 acute and late toxicities were reported by the Common Terminology Criteria for Adverse Events v5.0.

RESULTS

One hundred and six medically unfit HNSC patients (112 lesions) were included. Median follow-up was 8 months. Median patient age at diagnosis was 86 years (range: 56-102 years). The majority of patients had advanced disease (overall stage III-IV [n = 90, 85%]) with median gross tumor volumes (GTV) of 31 cm³ (range: 17-56 cm³). Treated sites were: primary (n = 51), nodal (n = 47) or primary plus nodal (n = 8). SBRT doses ranged from 32-50 Gy delivered twice weekly in 4-6 fractions to the gross tumor volume (GTV). One and 2-year LC rates were 78% (69-88) and 67% (53-82), respectively. One-year LRC outside of SBRT field, OS, PFS and LT rates were 72% (62-84), 53% (43-65), 52% (40-62), and 7% (2-17), respectively. Thirty-three patients (31%) developed acute grade ≥ 3 treatment-related toxicity, most commonly dermatitis (n = 31). Nine patients (8%) experienced late grade ≥ 3 toxicity, including 7 grade 3 fibrosis, 1 grade 3 bone radionecrosis and 1 grade 4 skin ulceration. No treatment-related deaths (grade 5) were observed.

CONCLUSION

SBRT provides durable disease control with acceptable toxicity for medically unfit high-risk HNSC patients unable to undergo standard of care curative treatment approaches.

The use of high frequency skin ultrasound in non-melanoma skin cancer

Ultrasound (US) or sonography is the most common diagnostic non-invasive imaging method, which is estimated to account for more than a third of all diagnostic procedures used in medical practice. Traditionally, US frequencies used in diagnostic radiology range from 1 MHz to approximately 16 MHz. Visualization of skin morphology requires US frequencies from 20 to 100 MHz, and is called a "high frequency ultrasound" (HFUS). HFUS has been explored in normal skin and in various skin pathologies. It has been found useful in differentiation diagnosis of infiltrative (perivascular) and exudative inflammation, hypertrophic or normotrophic scars, keloids, and in skin atrophy. Moreover, it has been used to support diagnosis and management of skin tumors. In skin oncology, HFUS can provide essential information on tumors' size and margins, particularly the depth of invasion. Such information are crucial in deciding on the form of treatment (e.g., photodynamic therapy, radiotherapy, brachytherapy), computed tomography (CT)-based planning treatment (e.g., superficial brachytherapy), and in skin monitoring after treatment, in addition to clinical examination.

Changes in Use of Radiotherapy Among Dermatologists From 2013 to 2017

Importance

Concerns have been raised about the use of radiotherapy (RT) by dermatologists. Little is known about temporal trends in payment for RT among dermatologists.

Objective

To characterize changes in RT use and payment among dermatologists treating patients enrolled in Medicare.

Design, Setting, and Participants

A cross-sectional, population-based retrospective analysis of dermatologists submitting Medicare claims was conducted. Dermatologists identified in the 2013-2017 Medicare Physician and Other Supplier Public Use File, which includes information on fee-for-service payments and service use among physicians caring for Medicare beneficiaries, were included in the analysis. The study was conducted from March 18 to October 22, 2020.

Main Outcomes and Measures

Numbers and types of RT, current terminology codes billed by dermatologists, number of dermatologists providing RT services, total payments and median payments per dermatologist for RT services, total services and median services per dermatologist, and number of dermatologists billing for both RT and Mohs micrographic surgery services.

Results

From 2013 to 2017, dermatologists billed RT codes, which included RT planning, preparation, delivery, and management services with varying levels of complexity. The number of dermatologists using RT increased from 115 to 198 between 2013 to 2017. Total payments and total services for RT have fluctuated over time. Median payments per dermatologist and median services provided per dermatologist for RT reached their highest level in 2017 ($80 810 and 629 services). In 2013, RT delivery was the highest reimbursed RT service type (total paid, $9 121 505). By 2017, clinical treatment planning and simulation was the highest reimbursed service type (total paid, $20 288 796).

Conclusions and Relevance

The findings of this cross-sectional study indicate that dermatologist use of RT continues to increase. A wide variety of RT services are billed by dermatologists. Further research is needed to ensure expanded use is safe, efficacious, and cost-effective.

[Place of radiotherapy in the treatment of cutaneous carcinomas]

Basal cell carcinomas and cutaneous squamous cell carcinomas are among the most common cancerous tumors in the world. Their treatment is most often based on surgery. Adjuvant radiotherapy may be indicated in case of risk factors for recurrence or as an alternative to surgery if surgery is not feasible due to the patient's advanced age and/or co-morbidities or as an alternative to potentially mutilating surgery. Radiotherapy is also part of the therapeutic arsenal for rarer skin tumors such as Merkel cell carcinoma, cutaneous lymphomas, Kaposi's disease and cutaneous adnexal carcinomas.

Phyto-Phospholipid Complexation as a Novel Drug Delivery System for Management of Cancer with Better Bioavailability: Current Perspectives and Future Prospects

Cancer is the foremost cause of death, and it supports the need for the identification of novel anticancer drugs to improve the efficacy of current-therapy. While the synthetic anticancer drug is associated with numerous side effects. Hence the plant active or phytoconstituents are in high demand for the treatment of cancer due to minimum side effects. But the polar nature of phytoconstituents hindered the absorption of the drug and lowered the therapeutic efficacy. The plant activity incorporated into Phyto-phospholipid Complexation can enhance bioavailability and improved therapeutic efficacy. In this review article, advantages, limitation and application of Phyto-phospholipid complexes have been illustrated. The article highlights the application of Phyto-phospholipid complexes as a promising drug carrier system to treat cancer.

Comparison of the Effect of Alpha and Hydrocortisone Ointments on Prevention of Acute Skin Complications Due to Radiotherapy in Breast Cancer Patients

Background

Radiotherapy in breast cancer patients is associated with acute and delayed side effects. This study aimed to compare the effect of alpha and hydrocortisone 1% (H1%) ointments on prevention of acute skin complications due to radiotherapy in breast cancer patients.

Methods

This clinical trial was conducted on 86 patients with breast cancer in the radiotherapy center of Imam Reza Hospital of Kermanshah, Iran. Using the records, the patients were selected and randomly divided into alpha and H1% groups after obtaining informed consent. The severity of dermatitis, complications, and patient complaints during treatment were evaluated weekly for up to 6 weeks by RTOG criteria. Data were analyzed using SPSS-16 software.

Results

At the end of the third, fourth, fifth, and sixth weeks, 10 (11.7%), 25 (29.1%), 53 (61.6%), and 28 (32.6%) patients had skin complications, respectively. In weeks 5 and 6 in the H1 group, the incidence of complications was higher (P = 0.001). The frequency of pain and burning complaints at the end of the third, fourth, fifth, and sixth weeks was 15 (17.4%), 37 (43.0%), 52 (60.5%), and 1(1.2%), respectively. Pain and burning intensity in the fourth and fifth weeks in the H1 group was lower than alpha (P = 0010). Complaints of skin itching at the end of the third, fourth, and fifth weeks were 16 (18.6%), 25 (29.1%), and 28 (32.6), respectively. This complication was lower in the H1% group during these weeks (P < 0.05).

Conclusion

Alpha ointment is more effective than H1% in relieving pain and burning, preventing complications except itching. It seems using an alpha ointment or combining it with H1% is an appropriate strategy to reduce the rate of injuries and skin complications of radiotherapy.

The role of radiation therapy in the management of cutaneous malignancies. Part I: Diagnostic modalities and applications

Radiation therapy offers distinct advantages over other currently available treatments for cutaneous malignancies in certain circumstances. Dermatologists and dermatologic surgeons should be familiar with the available radiation therapy techniques as well as their value and potential limitations in a variety of clinical scenarios. The first article in this 2-part continuing medical education series highlights the mechanisms, modalities, and applications of the most commonly used radiotherapy treatments as they relate to cutaneous oncology. We review the current indications for the use of radiation in the treatment of various cutaneous malignancies, the techniques commonly employed in modern radiotherapy, and the associated complications.

Impact of the Spectral Composition of Kilovoltage X-rays on High-Z Nanoparticle-Assisted Dose Enhancement

Nanoparticles (NPs) with a high atomic number (Z) are promising radiosensitizers for cancer therapy. However, the dependence of their efficacy on irradiation conditions is still unclear. In the present work, 11 different metal and metal oxide NPs (from Cu (Z_Cu = 29) to Bi₂O₃ (Z_Bi = 83)) were studied in terms of their ability to enhance the absorbed dose in combination with 237 X-ray spectra generated at a 30–300 kVp voltage using various filtration systems and anode materials. Among the studied high-Z NP materials, gold was the absolute leader by a dose enhancement factor (DEF; up to 2.51), while HfO₂ and Ta₂O₅ were the most versatile because of the largest high-DEF region in coordinates U (voltage) and E_eff (effective energy). Several impacts of the X-ray spectral composition have been noted, as follows: (1) there are radiation sources that correspond to extremely low DEFs for all of the studied NPs, (2) NPs with a lower Z in some cases can equal or overcome by the DEF value the high-Z NPs, and (3) the change in the X-ray spectrum caused by a beam passing through the matter can significantly affect the DEF. All of these findings indicate the important role of carefully planning radiation exposure in the presence of high-Z NPs.

Radiation therapy of non-melanoma skin cancer of the pinna: an Italian 35-years experience

BACKGROUND

Radiation therapy (RT) is a well known alternative to surgery for the treatment of non-melanoma skin cancer (NMSC), especially in elderly people or in patients who can not undergo or refuse surgical procedure. It has also a pivotal role in those areas, as pinna, where both function and cosmesis must be preserved. We report our experience in treating cutaneous carcinoma of the auricle with radiation therapy.

METHODS

We conducted a retrospective monocentric study on 363 NMSC of the auricle treated by conventional energy radiation therapy as a primary treatment or with adjuvant and salvage purpose. Tumors involving the external canal of the ear or regional lymph node at diagnosis were excluded.

RESULTS

A complete response has been obtained in 95.5% with a 2- and 5-years cure rate respectively of 84% and 76%. Fifty-two tumors developed a central or marginal relapse. Aesthetic result was good or acceptable in the majority of the cases. No cartilage necrosis has been registered.

CONCLUSIONS

Our experience confirms safety and effectiveness of RT on selected auricle carcinoma, affording good cosmetic and functional results.

High-dose-rate brachytherapy for non-melanoma skin cancer using tailored custom moulds - a single-centre experience

AIM OF THE STUDY

The aim of this retrospective study was to analyse tumour control, toxicity, and aesthetic outcome of patients affected by non-melanoma skin cancer (NMSC) treated with 192 Ir high-dose-rate (HDR)-brachytherapy (BT) at the Division of Radiotherapy, University of Pisa.

MATERIAL AND METHODS

From January 2014 to December 2019 we treated 37 patients (median age 79 years; range 31-91 years) affected by NMSC, with the following histological subtypes: 62.2% basal cell carcinoma and 37.8% squamous cell carcinoma. We analysed 40 lesions with a depth ≤ 5 mm, located in 40.0% scalp, 17.5% nose, 25.0% face, and 17.5% ear, all treated with 192 Ir-based HDR-BT, using tailored custom moulds, with a median of 5 catheters (range, 1-9) spaced 1 cm apart. The most common fractionation scheme was 40 Gy in 8 daily fractions; the biological effective dose was 60 Gy.

RESULTS

The median follow-up was 25 months (range, 3-70 months). The 2-year local control rate was 90%. Common terminology criteria for adverse event (CTCAE vs. 5.0) G1 toxicities were dermatitis (52%), pain (25%), and ulceration (22%). The only G2 acute toxicities were dermatitis and ulceration. The most common G1 late toxicities were fibrosis (17%), atrophy (15%), and hypopigmentation (12%). No G3 or higher acute or late toxicity was reported. Excellent cosmetic results were observed in 65.0% of the lesions; only 1 case (2.5%) reported a poor cosmetic result.

CONCLUSIONS

Surface mould HDR-BT is a safe, effective, and well tolerated treatment modality for NMSC and can be considered a good alternative, especially for elderly patients who are often unfit for surgery.

Neoadjuvant Therapy for Non-melanoma Skin Cancer: Updated Therapeutic Approaches for Basal, Squamous, and Merkel Cell Carcinoma

OPINION STATEMENT

Recently introduced systemic therapies for locally advanced and metastatic non-melanoma skin cancers (NMSCs) are paving the way for neoadjuvant approach. Although none of the therapeutic options has currently gained indication in this setting, neoadjuvant approach for NMSCs is an open field and we are likely to see huge developments in the near future. Targeted therapy with sonic hedgehog pathway inhibitors is very effective in locally advanced or multiple basal cell carcinomas while immunotherapy with immune checkpoint inhibitors appears to be promising for advanced cutaneous squamous cell carcinoma and Merkel cell carcinoma. To date, targeted therapy and immunotherapy represent the frontiers in NMSC therapeutic management and, according to recent studies, good results can be achieved.

High-dose-rate brachytherapy for facial skin cancer: Outcome and toxicity assessment for 71 cases

PURPOSE

In France, the reference technique for skin cancer was low-dose-rate brachytherapy (BT) delivered via iridium wire. At the end of their commercialization in 2015 we have replaced them by high-dose-rate (HDR) BT via interstitial catheters. We assessed efficacy and tolerance as soon as this technique was implemented.

METHODS AND MATERIALS

Patients received 7 Gy on the first day, followed by 8 × 4 Gy over the next 4 days for exclusive BT and 9 × 4 Gy over 5 days for post-operative BT.

RESULTS

Sixty-six patients of median age 81 years received a total of 58 primary BT and 13 post-operative BT for non-melanoma facial skin cancers. Implantation was without difficulty. Median follow up was 15.3 months. Two patients died of intercurrent diseases before first follow up. For the others, 98.5% showed complete response and 3% local recurrence after a median of 20.5 months. Four patients had grade 3 acute dermatitis and three patients had grade 3 mucositis. All the Grade 3 toxicities were resolved within 3 months. A late significant hypopigmentation occurred in 4 patients.

CONCLUSIONS

HDR BT is efficient and well-tolerated with good cosmetic results. HDR catheters are similar with iridium wires in terms of technical difficulty.

The Treatment of Non-Melanoma Skin Cancer with Image-Guided Superficial Radiation Therapy: An Analysis of 2917 Invasive and In Situ Keratinocytic Carcinoma Lesions

Introduction

An image-guided form of superficial ionizing radiation therapy (IGSRT) is becoming a commonly used alternative to surgery for non-melanoma skin cancer (NMSC). However, there is little literature evidence evaluating the efficacy and safety of this approach. This study evaluates the efficacy and safety of IGSRT in treating a large number of patients with NMSC.

Methods

The medical records of 1632 stage 0–II patients with 2917 invasive and in situ NMSC lesions treated from years 2017 to 2020 were reviewed. No patients had clinical evidence of regional lymph node or distant disease at presentation.

Results

Treatment, guided by pre-treatment ultrasound imaging to adjust radiation energy and dose, combined with a fractionation treatment schedule of 20 or more treatment fractions, was safe and well tolerated. Of 2917 NMSC lesions treated, local tumor control was achieved in 2897 lesions, representing a 99.3% rate of control.

Conclusion

IGSRT should be considered as a first-line option for treating NMSC tumors in suitable early stage patients. Cure rates observed in this initial period of follow-up are similar, and potentially superior with further follow-up, to traditional superficial radiation therapy (SRT) and surgical options.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40487-021-00138-4.

A retrospective study comparing different injection approaches of 5-aminolevulinic acid in patients with non-melanoma skin cancer

BACKGROUND

5-aminolevulinic acid through a needle-free, plum-blossom needle or conventional needle followed by photodynamic therapy are available options for non-melanoma skin cancer treatment.

AIM

To compare these three techniques of injection of 5-aminolevulinic, regarding treatment response and adverse effects in patients with non-melanoma skin cancer.

PATIENTS AND METHODS

Non-melanoma skin cancer patients have received six cycles of 0.5 mL intralesional 20% w/v 5-aminolevulinic acid through a conventional needle (CPT cohort, n = 158), or plum-blossom needle (BPT cohort, n = 118), or needle-free injection (NPT cohort, n = 105) followed by irradiation with a red light. Data regarding treatment response and adverse effects were collected and analyzed.

RESULTS

The treatment response was higher among patients of NPT cohort than those of CPT (p = .012, q = 3.981) and BPT (p = .012, q = 3.472) cohorts. Conventional and plum-blossom needle injections therapies were reported scar, local redness, and worse cosmetic appearance in the follow-up period.

CONCLUSIONS

Needle-free injection of intralesional 5-aminolevulinic acid followed by irradiation with red light therapy were reported high treatment response with manageable adverse effects for non-melanoma skin cancer patients than that of conventional and plum-blossom needle injections.

LEVEL OF EVIDENCE

III.

Brachytherapy in Belgium in 2018. A national survey of the brachytherapy study group of the Belgian SocieTy for Radiotherapy and Oncology (BeSTRO)

PURPOSE

To explore the current practices patterns and evaluate the actual brachytherapy (BT) resources in Belgium.

MATERIAL AND METHODS

In 2019, the Brachytherapy Study Group proposed to conduct a survey on behalf of the Belgian SocieTy of Radiation Oncology (BeSTRO) in order to identify current BT practice patterns. An electronic questionnaire was sent to all primary radiotherapy centers in Belgium. This questionnaire was based on the questionnaire that was used by the Italian Association of Radiation Oncology (AIRO) in 2016, asking for: (a) General information on the Radiation Oncology Centre; (b) BT equipment and human resources; (c) BT procedures; (d) BT assessment (number of patients treated annually, treated sites, and different modalities of treatments).

RESULTS

All 24 radiation oncology centers (100% response rate) answered the questionnaire and gave also information on the performance of brachytherapy in their (eventual) satellite centers. Eighteen (18) BT afterloader units were installed and operational in 2018. Thirteen centers mentioned a prostate seed implant program, one center a prostate and eye plaque program and one center only an eye plaque program. Less than 50% of centers have the infrastructure to offer the full-range of BT in their own department. In 2018, 1486 patients received a BT-treatment, 28% of them were treated by prostate seed implant, 8% were treated by eye-(seed) BT and 64% by high dose rate (HDR)/pulsed dose rate (PDR) BT. Forty-five percent of HDR/PDR patients were treated by vaginal dome BT, 22% by intra-uterine BT, 11% by skin BT, 10% by breast BT (almost exclusively in one centre), 8% for benign pathology (keloid) and the remaining 4% were treated for prostate (as a boost or as salvage in one centre), anal, penile, lung or oesophageal cancer.

CONCLUSIONS

Belgian radiotherapy departments often perform BT only in a (highly) selected group of pathologies, resulting in a limited number of patients treated by this technique despite the sufficient availability of BT equipment. Modern indications are often not covered, hence patients do not have regular access to recognized treatment options, possibly leading to inferior oncological outcome. BeSTRO will use the results of this survey to stimulate improvements in training, awareness, education, implementation, collaboration and cooperation in the field of brachytherapy.

The American Brachytherapy society consensus statement for skin brachytherapy

PURPOSE

Keratinocyte carcinoma (KC, previously nonmelanoma skin cancer) represents the most common cancer worldwide. While surgical treatment is commonly utilized, various radiation therapy techniques are available including external beam and brachytherapy. As such, the American Brachytherapy Society has created an updated consensus statement regarding the use of brachytherapy in the treatment of KCs.

METHODS

Physicians and physicists with expertise in skin cancer and brachytherapy created a consensus statement for appropriate patient selection, data, dosimetry, and utilization of skin brachytherapy and techniques based on a literature search and clinical experience.

RESULTS

Guidelines for patient selection, evaluation, and dose/fractionation schedules to optimize outcomes for patients with KC undergoing brachytherapy are presented. Studies of electronic brachytherapy are emerging, although limited long-term data or comparative data are available. Radionuclide-based brachytherapy represents an appropriate option for patients with small KCs with multiple techniques available.

CONCLUSIONS

Skin brachytherapy represents a standard of care option for appropriately selected patients with KC. Radionuclide-based brachytherapy represents a well-established technique; however, the current recommendation is that electronic brachytherapy be used for KC on prospective clinical trial or registry because of a paucity of mature data.

The dosimetric effect of variations in source position on treatments using Leipzig-style brachytherapy skin applicators

Leipzig-style skin brachytherapy applicators are an excellent choice for the treatment of small surface lesions, since they can be used with a high dose rate source to produce a tightly constrained treatment field on the desired area of the skin. The dosimetry of these applicators is challenging to independently verify due to their small dimensions, complex energy spectrum and steep dose gradients. In particular the close proximity of the brachytherapy source to the treatment region is cause for concern, since small variations in the position of the radioactive source may significantly affect the resulting dose distribution. The aim of this work was to assess the dosimetry of these applicators using three independently techniques and use these results to examine the effect of variation in source position on the dose distribution. Simulation of different sized applicators in conjunction with a Gammamed + Ir¹⁹² source was performed using the EGSnrc Monte Carlo code. Dose distributions at the prescription depth and at the surface generated by Monte Carlo were compared to the outputs of a commercially available treatment planning system and measurements using radiochromic film. Source displacements of up to 0.5 mm in the vertical direction, 0.65 mm in the horizontal direction, and rotations of the source by up to 5° were all simulated. Changes in dose of over 6% at the prescription point and reductions in coverage at the 100% isodose level of several millimetres were observed even for small shifts of the source from its intended position. This work demonstrates that variation in the position of the radiation source is the dominant source of uncertainty in the use of these types of applicators. Centres wishing to perform treatments using these applicators are advised to take steps to control the uncertainty and ensure it remains at an acceptable level.

Vitamin D, gut microbiota, and radiation-related resistance: a love-hate triangle

Radiation resistance is a serious issue in radiotherapy. Increasing evidence indicates that the human gut microbiome plays a role in the development of radiation resistance. Vitamin D is an important supplement for cancer patients treated with radiotherapy. Against this background, this paper reviewed research regarding the associations among vitamin D, microbiota dysbiosis, and radiation resistance. A hypothesis is developed to describe the relationships among vitamin D, the gut microbiota, and radiotherapy outcomes. Radiotherapy changes the composition of the gut microbiota, which in turn influence the serum level of vitamin D, and its distribution and metabolism in the body. Alteration of vitamin D level influences the patient response to radiotherapy, where the underlying mechanisms may be associated with the intestinal microenvironment, immune molecules in the intestines, gut microbiome metabolites, and signaling pathways associated with vitamin D receptors. Our understanding of the contribution of vitamin D and the gut microbiota to radiotherapy outcomes has been increasing gradually. A better understanding of the relationships among vitamin D, the gut microbiota, and radiotherapy outcomes will shed more light on radiation resistance, and also promote the development of new strategies for overcoming it, thus addressing an important challenge associated with the currently available radiotherapy modalities for cancer patients.

Electrochemotherapy and Ablative Therapies in Non-melanoma Skin Cancer

Although surgery and radiotherapy remain the most commonly used treatments for non-melanoma skin cancer, there are a variety of alternatives. Here we discuss the use of electrochemotherapy and ablative treatments and examine the evidence for their effectiveness against a number of non-melanoma skin cancers.