Clinical Outcomes of Proton Radiotherapy for Uveal Melanoma

Robot-assisted system for non-invasive wide-range flexible eye positioning and tracking in particle radiotherapy

Particle (proton, carbon ion, or others) radiotherapy for ocular tumors is highly dependent on precise dose distribution, and any misalignment can result in severe complications. The proposed eye positioning and tracking system (EPTS) was designed to non-invasively position eyeballs and is reproducible enough to ensure accurate dose distribution by guiding gaze direction and tracking eye motion. Eye positioning was performed by guiding the gaze direction with separately controlled light sources. Eye tracking was performed by a robotic arm with cameras and a mirror. The cameras attached to its end received images through mirror reflection. To maintain a light weight, certain materials, such as carbon fiber, were utilized where possible. The robotic arm was controlled by a robot operating system. The robotic arm, turntables, and light source were actively and remotely controlled in real time. The videos captured by the cameras could be annotated, saved, and loaded into software. The available range of gaze guidance is 360° (azimuth). Weighing a total of 18.55 kg, the EPTS could be installed or uninstalled in 10 s. The structure, motion, and electromagnetic compatibility were verified via experiments. The EPTS shows some potential due to its non-invasive wide-range flexible eye positioning and tracking, light weight, non-collision with other equipment, and compatibility with CT imaging and dose delivery. The EPTS can also be remotely controlled in real time and offers sufficient reproducibility. This system is expected to have a positive impact on ocular particle radiotherapy.

External Beam Radiotherapy in the Management of Uveal Melanoma

OPINION STATEMENT

Uveal melanoma is the most common primary ocular tumor in adults. With the evidence demonstrating that episcleral plaque brachytherapy (EPB) has similar survival rates as enucleation in the Collaborative Ocular Melanoma Study (COMS), eye-sparing treatments have come to the fore today. External radiotherapy techniques (proton beam radiotherapy and stereotactic radiosurgery/fractionated stereotactic radiosurgery) are an important treatment option for globe-sparing treatments. There are no prospective randomized trials comparing these techniques; however, retrospective series, meta-analyses, and reviews indicate that these EPB and external radiotherapy techniques are equal. With this review, we aimed to examine the external radiotherapy techniques used in the treatment of uveal melanoma in detail with reference to the current literature.

Current and Emerging Radiotherapy Options for Uveal Melanoma

What treatment options are there for patients having uveal melanoma? A randomized, prospective, multi-institutional clinical trial (COMS) showed no difference in survival between brachytherapy and enucleation for medium-sized lesions. With the obvious benefit of retaining the eye, brachytherapy has flourished and many different approaches have been developed such as low-dose-rate sources using alternate low-energy photon-emitting radionuclides, different plaque designs and seed-loading techniques, high-dose-rate brachytherapy sources and applicators, and low- and high-dose-rate beta-emitting sources and applicators. There also have been developments of other radiation modalities like external-beam radiotherapy using linear accelerators with high-energy photons, particle accelerators for protons, and gamma stereotactic radiosurgery. This article examines the dosimetric properties, targeting capabilities, and outcomes of these approaches. The several modalities examined herein have differing attributes and it may be that no single approach would be considered optimal for all patients and all lesion characteristics.

From Molecular Biology to Novel Immunotherapies and Nanomedicine in Uveal Melanoma

Molecular biology studies of uveal melanoma have resulted in the development of novel immunotherapy approaches including tebentafusp-a T cell-redirecting bispecific fusion protein. More biomarkers are currently being studied. As a result, combined immunotherapy is being developed as well as immunotherapy with bifunctional checkpoint inhibitory T cell engagers and natural killer cells. Current trials cover tumor-infiltrating lymphocytes (TIL), vaccination with IKKb-matured dendritic cells, or autologous dendritic cells loaded with autologous tumor RNA. Another potential approach to treat UM could be based on T cell receptor engineering rather than antibody modification. Immune-mobilizing monoclonal T cell receptors (TCR) against cancer, called ImmTAC TM molecules, represent such an approach. Moreover, nanomedicine, especially miRNA approaches, are promising for future trials. Finally, theranostic radiopharmaceuticals enabling diagnosis and therapy with the same molecule bring hope to this research.

Quality of life among people with eye cancer: a systematic review from 2012 to 2022

BACKGROUND

Eye cancer is a serious eye disease that threatens patients' lives. In the past decade, there have been more and more studies on eye cancer. From the recently published eye cancer literature review, it can be seen that the two most popular research hotspots are retinoblastoma (RB) and uveal melanoma (UM) [1, 2]. Although several studies have assessed QOL in different types of eye cancer patients, a study that synthesizes the factors influencing QOL in eye cancer patients is yet to be undertaken. This study aimed to review and evaluate the literature related to the QOL of RB and UM survivors, and provide a synthesis of the current evidence on the impact of the two types of eye cancer on the overall QOL of patients.

METHODS

Eight databases (APA Psych Articles, CINAHL Complete, Health Source: Nursing/Academic Edition, MEDLINE Complete, Scopus, Cochrane Library, PubMed, and Registers (Clinicaltrials.gov.)) were searched between January 2012 and December 2022 for English, peer-reviewed quantitative original studies within this review. All publications were screened using the Preferred Reporting Items for Systematic Review and Meta-Analyses reporting guidelines. The methodological quality of the reviews was assessed using the Joanna Briggs Institute Critical Appraisal Checklists. The findings were summarised and tabulated accordingly.

RESULTS

Seventeen articles were analysed. Among them, 14 articles on patients with UM, and three articles on patients with RB using 18 different types of measurement tools were included. Eight researchers claimed that the overall QOL of patients with eye cancer was better than or similar to that of the general healthy population. However, nine studies indicated that these patients had poorer QOL than others. Many factors affect QOL, including treatment, sex, and age.

CONCLUSION

This systematic review identified the QOL levels and several factors that influence the QOL of ocular cancer patients worldwide, due to the variability in quality of the studies, it also showed the need for further research to assess factors affecting long-term QOL outcomes in RB and UM survivors. Simultaneously, it clarified the necessity and importance of developing standardized and complete assessment tools to compare QOL in different countries. Early interventions can be developed to improve the survivors' QOL by identifying potential deficits in specific areas.

Factors affecting eye conservation and metastasis in posterior uveal melanomas

PURPOSE

To determine the effect of patient and tumor features and different treatments on eye removal (enucleation or exenteration) and metastasis in posterior uveal melanoma (PUM).

METHODS

Retrospective analysis. Patient age (≤60 vs >60 years), sex (female vs male), visual acuity (VA, ≤20/40 vs >20/40), largest tumor basal diameter (LTBD), tumor thickness, tumor stage according to American Joint Committee on Cancer (AJCC) 8th edition, ciliary body involvement, distance to optic disc (OD)/fovea (≤3 mm vs >3 mm), OD involvement, and histopathology were evaluated. Primary treatment options were transpupillary thermotherapy, plaque radiotherapy, Cyberknife radiosurgery, exoresection, and eye removal. Risk factors for primary eye removal were determined using logistic regression test and those for secondary eye removal and metastasis with Cox regression analysis.

RESULTS

Of 387 cases, 153 (39.5%) underwent primary eye removal. Multivariable risk factors for primary eye removal included AJCC tumor stage (p = 0.001, OR:4.586; p < 0.001, OR:34.545; p < 0.001, OR:103.468 for stages T2, T3, and T4 vs stage T1, respectively), and VA≤20/40 (p = 0.014, OR:2.597). Multivariable risk factors for secondary eye removal were VA≤20/40 (p = 0.019, RR:2.817) and AJCC stage T3 vs T1 (p = 0.021, RR:2.666). Eye preservation rates in patients undergoing eye-conserving treatments were 80.3%, 69.6%, and 51.5% at 5, 10, and 15 years, respectively. Metastasis-free survival rates were 81.0%, 73.0%, and 56.7% at 5, 10, and 15 years, respectively. Multivariable risk factors for metastasis included eye removal as primary treatment (p = 0.005, RR:2.828) and mixed type histopathology (p < 0.001, RR:4.804).

DISCUSSION

Early diagnosis is crucial for both eye preservation and survival in PUM. Increasing AJCC tumor stage and lower VA were risk factors for eye removal in this study. Mixed type histopathology and primary eye removal were risk factors for metastasis.

Radiotherapy in Uveal Melanoma: A Review of Ocular Complications

Uveal melanoma represents the most prevalent form of primary malignant intraocular tumor in adults. Historically, enucleation was considered the gold-standard approach in the treatment of uveal melanoma. Currently, radiotherapy is the most commonly used therapy, aiming at a better quality of life. However, radiotherapy can result in several ocular complications, some of which may be vision-threatening. Radiation-induced dry eye, scleral necrosis, cataract, rubeosis iridis, neovascular glaucoma, radiation retinopathy, maculopathy, and optic neuropathy are the most common complications. This article aims to summarize the current literature regarding the ocular complications after radiotherapy, as well as their clinical features, risk factors, and management strategies. A thorough understanding of these issues is crucial for ophthalmologists and oncologists to provide optimal patient care, improve visual outcomes, and minimize long-term complications.

Design and characterization of an aperture system and spot configuration for ocular treatments with a gantry-based spot scanning proton beam

BACKGROUND AND PURPOSE

Proton therapy is a key modality used in the treatment of ocular melanoma. Traditionally ocular sites are treated using a dedicated eyeline with a passively scattered proton beam and a brass aperture. This work aims to design and characterize a beam-collimating aperture to treat ocular targets with a gantry-based spot scanning proton beam.

METHODS

A plastic aperture system that slides into the gantry nozzle of a spot scanning proton beam was designed and constructed. It consists of an intermediate scraper layer to attenuate stray protons and a 3D-printed patient-specific aperture positioned 5.7 cm from the surface of the eye. The aperture system was modeled in TOPAS and Monte Carlo simulations were validated with film measurements. Two different spot configurations were investigated for treatment planning and characterized based on lateral penumbra, central axis (CAX) dose and relative efficiency. Alignment and leakage were investigated through experimental film measurements. Range was verified using a multi-layer ionization chamber. Reference dose measurements were made with a PinPoint 3D ion chamber. Neutron dose was evaluated through Monte Carlo simulations.

RESULTS

Aperture alignment with radiation isocenter was determined to be within 0.31 mm at a gantry angle of 0°. A single-spot configuration with a 10 mm diameter aperture yielded film-measured lateral penumbras of 1 mm to 1.25 mm, depending on depth in the spread-out Bragg peak. TOPAS simulations found that a single spot configuration results in a flat dose distribution for a 10 mm diameter aperture and provides a CAX dose of less than 106% for apertures less than 14 mm in diameter. For larger targets, adding four corner spots to fill in the dose distribution is beneficial. Trade-offs between lateral penumbra, CAX dose and relative efficiency were characterized for different spot configurations and can be used for future clinical decision-making. The aperture was experimentally determined to not affect proton beam range, and no concerning leakage radiation or neutron dose was identified. Reference dose measurements with a PinPoint ion chamber were within 2.1% of Monte Carlo calculated doses.

CONCLUSION

The aperture system developed in this work provides a method of treating ocular sites on a gantry-based spot scanning proton system. Additional work to develop compatible gaze tracking and gating infrastructure is ongoing.

Proton beam radiotherapy for choroidal and ciliary body melanoma in the UK-national audit of referral patterns of 1084 cases

INTRODUCTION

Proton beam therapy has been utilised for the treatment of uveal melanoma in the UK for over 30 years, undertaken under a single centre. In the UK, all ocular tumours are treated at one of four centres. We aimed to understand the variation in referral patterns to the UK proton service, capturing all uveal melanoma patients treated with this modality.

METHODS

Retrospective analysis of data regarding all patients treated at the Clatterbridge Proton service between January 2004 and December 2014.

RESULTS

A total of 1084 patients with uveal melanoma were treated. The mean age was 57 years (range 9-90 years), basal diameter of 11.5 mm (range 2.0-23.4 mm) and tumour thickness of 3.9 mm (range 0.1-15.4 mm). The majority were TNM stage I (39%) or II (36%). The distance to the optic nerve varied from 0 to 24.5 mm with 148 (14%) of patients having ciliary body involvement. There were variations in the phenotypic characteristic of the tumours treated with protons from different centres, with London referring predominantly small tumours at the posterior pole, Glasgow referring large tumours often at the ciliary body and Liverpool sending a mix of these groups.

DISCUSSION

In the UK, common indications for the use of proton treatment in uveal melanoma include small tumours in the posterior pole poorly accessible for plaque treatment (adjacent to the disc), tumours at the posterior pole affecting the fovea and large anterior tumours traditionally too large for brachytherapy. This is the first UK-wide audit enabling the capture of all patients treated at the single proton centre.

Ocular Complications of Radiotherapy in Uveal Melanoma

Uveal melanoma is the most common primary malignant intraocular tumor in adults. Radiation therapy has replaced enucleation and is now the preferred treatment in most cases. Nonetheless, around 70% of patients develop radiation-related complications, some of which are vision-threatening. The objective of this review is to present the most important complications associated with radiotherapy in the treatment of uveal melanoma and their pathogenesis, incidence, risk factors, and available preventive and therapeutic measures. The most common complications are cataracts, with a reported incidence ranging from 4% to 69%, and radiation retinopathy, reported in 5-68% of cases. Radiation-related complications are responsible for approximately half of secondary enucleations, the leading cause being neovascular glaucoma. A poor visual outcome is mainly associated with the presence of radiation retinopathy and radiation optic neuropathy. Therapeutic options are available for the majority of complications with the notable exception of optic neuropathy. However, many studies report a final visual acuity of less than 20/200 in more than 60% of treated eyes. Reducing complication rates can be achieved by lowering the dose of radiation, with the use of eccentric, customized plaques and careful planning of the irradiation delivery in order to protect structures vital to vision and by associating radiation therapy with other methods with the aim of reducing tumor volume.

Impact of Adjuvant Ocular Interventions on the Quality of Life of Patients with Uveal Melanoma after Proton Beam Therapy

INTRODUCTION

Proton beam therapy is an established primary treatment for patients with nonmetastasized uveal melanoma. Adjuvant local interventions, like intravitreal injections or surgery, were shown to improve long-term eye preservation; however, their impact on the patient's quality of life (QOL) remains unknown.

METHODS

In a post-radiotherapeutic follow-up, we prospectively collected data on QOL, visual acuity, and interventional adjuvant procedures. QOL was measured with QOL-C30 questionnaire and quality of life questionnaire OPT30 at baseline, and at 3 and 12 months after proton therapy. Patients were grouped by the type of adjuvant treatment. The impact on QOL was analyzed by comparing changes in the mean score values and visual acuity for different interventional subgroups, with generalized linear mixed models and Wilcoxon signed-rank tests.

RESULTS

We received 108 (100%) and 95 (88.0%) questionnaires at 3 and 12 months post-therapy, respectively. Adjuvant interventions included observation (n = 61, 56.5%), intravitreal injections (n = 17, 15.7%), and an intraocular surgical procedure (n = 30, 27.8%). In the latter group, several QOL items significantly declined after the 3-month adjuvant interval, but they partially recovered at the 12-month follow-up. In all adjuvant-intervention groups, global QOL scores returned to baseline levels at 12 months.

CONCLUSION

Posttreatment adjuvant interventions had no long-lasting effects on QOL in patients with uveal melanoma.

Uveal melanoma diagnosis and current treatment options (Review)

Uveal melanoma is a rare condition accounting for only 5% of all primary melanoma cases. Still, it is the most frequently diagnosed primary intraocular malignant tumor in adults. Almost 90% of the tumors involve the choroid and only a small percentage affects the ciliary body or the iris. There is a consistent difference in incidence between different regions with individuals of northern European descent having a significantly higher risk as compared to Hispanics, Asians, and Blacks. Among the many risk factors, mutations in the G protein subunit alpha Q (GNAQ) or G protein subunit alpha 11 (GNA11) genes and different receptors are highly suggestive. While iris melanoma can easily be noticed by the patient itself or diagnosed at a routine slit-lamp evaluation, a consistent percentage of posterior uveal tumors are incidentally diagnosed at funduscopic evaluation as they can evolve silently for years, especially if located in the periphery. Uveal melanoma classifications rely on the tumor size (thickness and basal diameter) and also on intraocular and extraocular extension. The differential diagnosis with pseudomelanomas is carried out according to the tumor aspect and position. Iris melanoma has a better prognosis and a lower mortality rate as compared to choroidal melanoma that has a much higher rate of metastasis (50% of the patients) and a subsequent limited life expectancy from 6 to 12 months. While conservative therapeutic options for the primary tumor, relying on different surgical excision techniques and/or irradiation therapies, offer good local tumor control, the treatment options for metastatic disease, although numerous, are still inadequate in preventing a fatal outcome.

Quality of life and treatment-related burden during ocular proton therapy: a prospective trial of 131 patients with uveal melanoma

BACKGROUND

Proton beam therapy is a well-established treatment option for patients with uveal melanoma (UM). The treatment procedure, in general, includes placing radiopaque clips to ensure exact eye-positioning during radiotherapy, followed by the delivery of proton irradiation. The short-term burden associated with proton therapy in patients with UM has rarely been addressed. In this prospective study, we investigated the physiological and psychological aspects of proton therapy that might affect the well-being of patients during the different stages of treatment.

METHODS

During the treatment procedure, we conducted longitudinal assessments of the Quality of life (QOL), organ-specific symptoms, and psychological aspects in patients with UM with three questionnaires (EORTC QLQ-C30, EORTC QLQ-OPT30, and GAD-7). Patients completed questionnaires before clip surgery (T0), before proton therapy (T1), after completing treatment (T2), and three months after treatment completion (T3). We also collected data on tumor characteristics and socio-demographics to identify potential risk factors associated with high treatment burdens.

RESULTS

We prospectively included 131 consecutive patients. Questionnaire data showed a significant, temporary decline in global QOL and an increase in eye-related symptoms, as a result of the clip surgery (T0-T1). After treatment completion (T2), global QOL improved gradually, and none of the eye-related symptoms significantly deteriorated over the course of proton therapy. The global QOL returned to baseline levels three months after treatment (T3). We identified baseline anxiety as an independent risk factor for experiencing an acute treatment-related burden. Furthermore, we found interactions between GAD7 and patient sex showing that anxiety had a more pronounced effect on QOL outcome in female patients.

CONCLUSION

The short-term treatment-related burden of ocular proton therapy appeared to be largely associated with the preceding clip surgery, rather than the irradiation procedure. We found that anxiety was strongly associated with experiencing QOL issues during the treatment procedure. Our findings could contribute to the development of future strategies for improving the treatment process and psycho-oncologic patient care.

Characterization of the HollandPTC proton therapy beamline dedicated to uveal melanoma treatment and an interinstitutional comparison

PURPOSE

Eye-dedicated proton therapy (PT) facilities are used to treat malignant intraocular lesions, especially uveal melanoma (UM). The first commercial ocular PT beamline from Varian was installed in the Netherlands. In this work, the conceptual design of the new eyeline is presented. In addition, a comprehensive comparison against five PT centers with dedicated ocular beamlines is performed, and the clinical impact of the identified differences is analyzed.

MATERIAL/METHODS

The HollandPTC eyeline was characterized. Four centers in Europe and one in the United States joined the study. All centers use a cyclotron for proton beam generation and an eye-dedicated nozzle. Differences among the chosen ocular beamlines were in the design of the nozzle, nominal energy, and energy spectrum. The following parameters were collected for all centers: technical characteristics and a set of distal, proximal, and lateral region measurements. The measurements were performed with detectors available in-house at each institution. The institutions followed the International Atomic Energy Agency (IAEA) Technical Report Series (TRS)-398 Code of Practice for absolute dose measurement, and the IAEA TRS-398 Code of Practice, its modified version or International Commission on Radiation Units and Measurements Report No. 78 for spread-out Bragg peak normalization. Energy spreads of the pristine Bragg peaks were obtained with Monte Carlo simulations using Geant4. Seven tumor-specific case scenarios were simulated to evaluate the clinical impact among centers: small, medium, and large UM, located either anteriorly, at the equator, or posteriorly within the eye. Differences in the depth dose distributions were calculated.

RESULTS

A pristine Bragg peak of HollandPTC eyeline corresponded to the constant energy of 75 MeV (maximal range 3.97 g/cm2 in water) with an energy spread of 1.10 MeV. The pristine Bragg peaks for the five participating centers varied from 62.50 to 104.50 MeV with an energy spread variation between 0.10 and 0.70 MeV. Differences in the average distal fall-offs and lateral penumbrae (LPs) (over the complete set of clinically available beam modulations) among all centers were up to 0.25 g/cm2 , and 0.80 mm, respectively. Average distal fall-offs of the HollandPTC eyeline were 0.20 g/cm2 , and LPs were between 1.50 and 2.15 mm from proximal to distal regions, respectively. Treatment time, around 60 s, was comparable among all centers. The virtual source-to-axis distance of 120 cm at HollandPTC was shorter than for the five participating centers (range: 165-350 cm). Simulated depth dose distributions demonstrated the impact of the different beamline characteristics among institutions. The largest difference was observed for a small UM located at the posterior pole, where a proximal dose between two extreme centers was up to 20%.

CONCLUSIONS

HollandPTC eyeline specifications are in accordance with five other ocular PT beamlines. Similar clinical concepts can be applied to expect the same high local tumor control. Dosimetrical properties among the six institutions induce most likely differences in ocular radiation-related toxicities. This interinstitutional comparison could support further research on ocular post-PT complications. Finally, the findings reported in this study could be used to define dosimetrical guidelines for ocular PT to unify the concepts among institutions.

In-field and out-of-field microdosimetric characterisation of a 62 MeV proton beam at CATANA

PURPOSE

A 5 and 10 μm thin silicon on insulator (SOI) 3D mushroom microdosimeter was used to characterize both the in-field and out-of-field of a 62 MeV proton beam.

METHODS

The SOI mushroom microdosimeter consisted of an array of cylindrical sensitive volumes (SVs), developed by the Centre for Medical Radiation Physics, University of Wollongong, was irradiated with 62 MeV protons at the CATANA (Centro di AdroTerapia Applicazioni Nucleari Avanzate) facility in Catania, Italy, a facility dedicated to the radiation treatment of ocular melanomas. Dose mean lineal energy, ( y D ¯ ), values were obtained at various depths in PMMA along a pristine and spread out Bragg peak (SOBP). The measured microdosimetric spectra at each position were then used as inputs into the modified Microdosimetric Kinetic Model (MKM) to derive the RBE for absorbed dose in a middle of the SOBP 2Gy (RBE_D ). Microdosimetric spectra were obtained with both the 5 and 10 μm 3D SOI microdosimeters, with a focus on the distal part of the BP. The in-field and out-of-field measurement configurations along the Bragg curve were modeled in Geant4 for comparison with experimental results. Lateral out-of-field measurements were performed to study secondary particles' contribution to normal tissue's dose, up to 12 mm from the edge of the beam field, and quality factor and dose equivalent results were obtained.

RESULTS

Comparison between experimental and simulation results showed good agreement between one another for both the pristine and SOBP beams in terms of y D ¯ and RBED. Though a small discrepancy between experiment and simulation was seen at the entrance of the Bragg curve, where experimental results were slightly lower than Geant4. The dose equivalent value measured 12 mm from the edge of the target volume was 1.27 ± 0.15 mSv/Gy with a Q ¯ value of 2.52 ± 0.30, both of which agree within uncertainty with Geant4 simulation.

CONCLUSIONS

These results demonstrate that SOI microdosimeters are an effective tool to predict RBED in-field as well as dose equivalent monitoring out-of-field to provide insight to probability of second cancer generation.

Iatrogenic Ocular Surface Diseases Occurring during and/or after Different Treatments for Ocular Tumours

Simple Summary

The ocular surface represents a finely regulated system that allows the protection of the eye. It can be affected by therapies used for the treatment of various intraocular tumours, particularly conjunctival cancers and uveal melanoma. In these conditions, treatments are chosen according to the characteristics of the lesion, and include a combination of selective surgery, anticancer eye drops, and/or radiotherapy delivered through different mechanisms. Possible side effects affecting the ocular surface range from transient dry eye or keratitis up to more severe complications such as corneal melting and perforation. These complications deserve careful evaluation for the risk of permanent sight-threatening sequelae. Physicians involved in the management of patients affected by ocular tumours should be aware of this risk in order to reach an early diagnosis and promptly set up an adequate treatment. The present review summarizes acute and chronic complications affecting the ocular surface following different therapies for the treatment of conjunctival cancers and uveal melanoma, and also reports clinical cases of representative patients who experienced these complications.

Abstract

The ocular surface represents a finely regulated system that allows the protection of the eye. It is particularly susceptible to different treatments for intraocular tumours, such as uveal melanoma and conjunctival cancers. Traditionally, the management of ocular tumours depends on the characteristics of the lesion, and is based on a combination of selective surgery, topical chemotherapy, and/or radiotherapy delivered through different mechanisms (e.g., charged-particle radiotherapy or brachytherapy). Possible complications involving the ocular surface range from transient dry eye disease or keratitis up to corneal melting and perforation, which in any case deserve careful evaluation for the risk of permanent sigh-threatening complications. Clinicians involved in the management of these patients must be aware of this risk, in order to reach an early diagnosis and promptly set up an adequate treatment. The present review of the literature will summarize acute and chronic complications affecting the ocular surface following different therapies for the treatment of ocular tumours.

Current molecular and clinical insights into uveal melanoma (Review)

Uveal melanoma (UM) represents the most prominent primary eye cancer in adults. With an incidence of approximately 5 cases per million individuals annually in the United States, UM could be considered a relatively rare cancer. The 90-95% of UM cases arise from the choroid. Diagnosis is based mainly on a clinical examination and ancillary tests, with ocular ultrasonography being of greatest value. Differential diagnosis can prove challenging in the case of indeterminate choroidal lesions and, sometimes, monitoring for documented growth may be the proper approach. Fine needle aspiration biopsy tends to be performed with a prognostic purpose, often in combination with radiotherapy. Gene expression profiling has allowed for the grading of UMs into two classes, which feature different metastatic risks. Patients with UM require a specialized multidisciplinary management. Primary tumor treatment can be either enucleation or globe preserving. Usually, enucleation is reserved for larger tumors, while radiotherapy is preferred for small/medium melanomas. The prognosis is unfavorable due to the high mortality rate and high tendency to metastasize. Following the development of metastatic disease, the mortality rate increases to 80% within one year, due to both the absence of an effective treatment and the aggressiveness of the condition. Novel molecular studies have allowed for a better understanding of the genetic and epigenetic mechanisms involved in UM biological activity, which differs compared to skin melanomas. The most commonly mutated genes are GNAQ, GNA11 and BAP1. Research in this field could help to identify effective diagnostic and prognostic biomarkers, as well as novel therapeutic targets.

Three-dimensional MRI-based treatment planning approach for non-invasive ocular proton therapy

PURPOSE

To develop a high-resolution three-dimensional (3D) magnetic resonance imaging (MRI)-based treatment planning approach for uveal melanomas (UM) in proton therapy.

MATERIALS/METHODS

For eight patients with UM, a segmentation of the gross tumor volume (GTV) and organs-at-risk (OARs) was performed on T1- and T2-weighted 7 Tesla MRI image data to reconstruct the patient MR-eye. An extended contour was defined with a 2.5-mm isotropic margin derived from the GTV. A broad beam algorithm, which we have called πDose, was implemented to calculate relative proton absorbed doses to the ipsilateral OARs. Clinically favorable gazing angles of the treated eye were assessed by calculating a global weighted-sum objective function, which set penalties for OARs and extreme gazing angles. An optimizer, which we have named OPT'im-Eye-Tool, was developed to tune the parameters of the functions for sparing critical-OARs.

RESULTS

In total, 441 gazing angles were simulated for every patient. Target coverage including margins was achieved in all the cases (V95%  > 95%). Over the whole gazing angles solutions space, maximum dose (Dmax ) to the optic nerve and the macula, and mean doses (Dmean ) to the lens, the ciliary body and the sclera were calculated. A forward optimization was applied by OPT'im-Eye-Tool in three different prioritizations: iso-weighted, optic nerve prioritized, and macula prioritized. In each, the function values were depicted in a selection tool to select the optimal gazing angle(s). For example, patient 4 had a T2 equatorial tumor. The optimization applied for the straight gazing angle resulted in objective function values of 0.46 (iso-weighted situation), 0.90 (optic nerve prioritization) and 0.08 (macula prioritization) demonstrating the impact of that angle in different clinical approaches.

CONCLUSIONS

The feasibility and suitability of a 3D MRI-based treatment planning approach have been successfully tested on a cohort of eight patients diagnosed with UM. Moreover, a gaze-angle trade-off dose optimization with respect to OARs sparing has been developed. Further validation of the whole treatment process is the next step in the goal to achieve both a non-invasive and a personalized proton therapy treatment.

Local tumour control and radiation side effects for fractionated stereotactic photon beam radiotherapy compared to proton beam radiotherapy in uveal melanoma

PURPOSE

To compare the adverse side effects of fractionated stereotactic photon beam radiotherapy (fSRT) with proton beam radiotherapy (PBR) in patients with uveal melanoma (UM).

METHODS

A retrospective study investigating 306 UM patients treated with fSRT (N=153) by the Rotterdam Ocular Melanoma Study group (ROMS), The Netherlands, between 1999-2014 or with PBR (N=153) at the Royal Liverpool University Hospital and the Clatterbridge Cancer Centre, Bebington, United Kingdom, between 1993-2014. The tumours treated with fSRT were matched with tumours treated with PBR based on sex, left or right eye, TNM classification, posterior margin ≤ or > 3mm of the fovea and of the optic disc.

RESULTS

The five-year actuarial rates of tumour recurrence were 4.5% for fSRT and 6.1% for PBR. For fSRT and PBR, the five-year actuarial rates of maculopathy were 14.9% and 12.4%, and for vitreous haemorrhage were 29.4% and 4.7%, respectively. Only vitreous haemorrhage (HR: 0.19, 95% CI: 0.07-0.56) was more common after fSRT compared to PBR. Overall, larger tumours were risk factors for maculopathy and secondary enucleation.

CONCLUSIONS

Both treatments have excellent local tumour control. In matched groups, vitreous haemorrhage was the only adverse side effect showing a significant difference between groups.

Measuring eye deformation between planning and proton beam therapy position using magnetic resonance imaging

•

Eye and tumour deformation due to gravity is less than 0.4 mm.

•

Conformity index between flexed and supine position for eyes is >0.95.

•

Conformity index between flexed and supine position for tumours is >0.85.

•

Supinely acquired MR images can be used for PBT planning.

Proton beam therapy (PBT) for uveal melanoma (UM) is performed in sitting position, while the acquisition of the Magnetic resonance (MR)-images for treatment planning is performed in supine position. We assessed the effect of this difference in position on the eye- and tumour- shape. Seven subjects and six UM-patients were scanned in supine and a seating mimicking position. The distances between the tumour/sclera in both positions were calculated. The median distance between both positions was 0.1 mm. Change in gravity direction produced no substantial changes in sclera and tumour shape, indicating that supinely acquired MR-images can be used to plan ocular-PBT.

PHOTODYNAMIC THERAPY AS PRIMARY TREATMENT FOR SMALL CHOROIDAL MELANOMA

PURPOSE

To report outcomes of photodynamic therapy (PDT) as primary treatment for small amelanotic choroidal melanoma.

METHODS

Retrospective interventional case series of 12 patients with small choroidal melanoma treated with standard-fluence PDT (83 seconds; 50 J/cm) using verteporfin.

OUTCOME MEASURES

Tumor regression, subretinal fluid resolution, best-corrected visual acuity, and PDT complications.

RESULTS

There were 12 eyes with melanoma, demonstrating amelanotic (10 [83%]) or lightly pigmented (n = 2, 17%) appearance. The mean tumor thickness was 2.7 mm (median, 2.8; range 1.8-3.7 mm). After PDT, mean follow-up was 56 months (median, 53; range, 14-91). Outcomes revealed complete tumor regression after 1 session (n = 3, 25%), 2 sessions (n = 3, 25%), and 3 sessions (n = 2, 17%) of PDT, reduced to mean thickness of 2.1 mm (median, 2.0; range 1.2-3.4 mm). Tumors that failed to regress (n = 4, 33%) were further controlled with transpupillary thermotherapy (n = 1) or plaque brachytherapy (n = 3). Subretinal fluid, present in six eyes, demonstrated resolution (n = 5) or progression (n = 1), and one tumor developed new subretinal fluid after PDT (n = 1). Visual outcome was stable (n = 11 eyes) or improved (n = 1). Photodynamic therapy complications included local retina pigment epithelium atrophy at the site of treatment in 3 (25%) eyes, with no effect on macular or optic nerve function.

CONCLUSION

Primary PDT resulted in complete tumor regression of small amelanotic choroidal melanoma in 67% at mean 5 years, with no major effect on visual acuity.

Efficacy and safety of carbon-ion radiotherapy for the malignant melanoma: A systematic review

Malignant melanomas (MMs) were the fifth most common cancer in men and the sixth most common cancer in women in 2018, respectively. These are characterized by high metastatic rates and poor prognoses. We systematically reviewed safety and efficacy of carbon-ion radiotherapy (CIRT) for treating MMs. Eleven studies were eligible for review, and the data showed that MM patients showed better local control with low recurrence and mild toxicities after CIRT. Survival rates were slightly higher in patients with cutaneous or uveal MMs than in those with mucosal MMs. CIRT in combination with chemotherapy produced higher progression-free survival rates than CIRT only. In younger patients, higher rates of distant metastases of gynecological MMs were observed. The data indicated that CIRT is effective and safe for treating MMs; however, a combination with systemic therapy is recommended to ensure the best possible prognosis for MMs.

Particle therapy toxicity outcomes: A systematic review

Owing to its physical properties, particle therapy (PT), including proton beam therapy (PBT) and carbon ion therapy (CIT), can enhance the therapeutic ratio in radiation therapy. The major factor driving PT implementation is the reduction in exit and integral dose compared to photon plans, which is expected to translate to reduced toxicity and improved quality of life. This study extends the findings from a recent systematic review by the current authors which concentrated on tumour outcomes for PT, to now examine toxicity as a separate focus. Together, these reviews provide a comprehensive collation of the evidence relating to PT outcomes in clinical practice. Three major databases were searched by two independent researchers, and evidence quality was classified according to the National Health and Medical Research Council evidence hierarchy. One hundred and seventy-nine studies were included. Most demonstrated acceptable and favourable toxicity results. Comparative evidence reported reduced morbidities and improvement in quality of life in head and neck, paediatrics, sarcomas, adult central nervous system, gastrointestinal, ocular and prostate cancers compared to photon radiotherapy. This suggestion for reduced morbidity must be counterbalanced by the overall low quality of evidence. A concerted effort in the design of appropriate comparative clinical trials is needed which takes into account integration of PT's pace of technological advancements, including evolving delivery techniques, image guidance availability and sophistication of planning algorithms.

Particle therapy tumour outcomes: An updated systematic review

Particle therapy (PT) offers the potential for reduced normal tissue damage as well as escalation of target dose, thereby enhancing the therapeutic ratio in radiation therapy. Reflecting the building momentum of PT use worldwide, construction has recently commenced for The Australian Bragg Centre for Proton Therapy and Research in Adelaide - the first PT centre in Australia. This systematic review aims to update the clinical evidence base for PT, both proton beam and carbon ion therapy. The purpose is to inform clinical decision-making for referral of patients to PT centres in Australia as they become operational and overseas in the interim. Three major databases were searched by two independent researchers, and evidence quality was classified according to the National Health and Medical Research Council evidence hierarchy. One hundred and thirty-six studies were included, two-thirds related to proton beam therapy alone. PT at the very least provides equivalent tumour outcomes compared to photon controls with the possibility of improved control in the case of carbon ion therapy. There is suggestion of reduced morbidities in a range of tumour sites, supporting the predictions from dosimetric modelling and the wide international acceptance of PT for specific indications based on this. Though promising, this needs to be counterbalanced by the overall low quality of evidence found, with 90% of studies of level IV (case series) evidence. Prospective comparative clinical trials, supplemented by database-derived outcome information, preferably conducted within international and national networks, are strongly recommended as PT is introduced into Australasia.

The Highlighted Role of GAPDH and Nitric-Oxide Synthase Regulator Activity in Proton Beam Irradiated Melanoma BLM Cells

Introduction: The human melanoma is a type of invasive tumor the treatment of which is challenging. To better understand the proton irradiation mechanisms as one of the widely applied therapy for this type of cancer, bioinformatics analysis of proteomics outcome could be beneficial. Methods: Protein-protein interaction network analysis of the differentially expressed proteins (DEPs) of melanoma BLM (BRO lung metastasis) cells in the treatment of 3 Gy dosage proton therapy was performed in this study via Cytoscape V.3.7.2. and its integrated plug-ins. Results: Eighteen DEPs were searched for network constructions and limited numbers of query +neighbor proteins were found central. The hub-bottlenecks (i.e. central nodes) were GAPDH, ACTB, ALB, AKT1, TP53, and EGFR. The fist mentioned proteins were from DEPs. The enrichment analysis of these elements identified nitric-oxide synthase regulator activity and the positive regulation of the norepinephrine uptake that may be the key to the mechanisms of proton therapy. Conclusion: In conclusion, the identified central nodes (EGFR, TP53, ALB, AKT1, GAPDH, and ACTB) and the related biological terms are the critical affected genes and biological terms in the irradiated melanoma cells.

Inhibition of DNA-PKcs activity re-sensitizes uveal melanoma cells to radio- and chemotherapy

Uveal melanoma (UM) is the most common primary intraocular tumor in adults. Despite of important progress in the local therapy, high radioresistance in primary tumor and chemoresistance in metastatic disease are the major obstacles for UM therapy. Therefore, strategies to overcome resistance to radiation or chemotherapy in UM are urgently needed. In this study, we found that phosphorylation of DNA-PKcs, which is the key factor of non-homologous end joining (NHEJ) pathway, was remarkably overexpressed in ionizing radiation (IR)- and Selumetinib resistant UM cells. Increased amount of NHEJ events were also observed in resistant UM cells. Inhibition of DNA-PKcs by NU7441 significantly impaired DNA repair and re-sensitized resistant UM cells to radiation and Selumetinib both in vitro and in vivo. The results demonstrate increased DNA double strand break repair as a mechanism of resistance to ionizing radiation and Selumetinib, and identify DNA-PKcs as a promising target for radio-and chemotherapy in UM patients.

Patterns of Care and Outcomes of Elderly Esophageal Cancer Patients Not Meeting Age-based Criteria of the CROSS Trial

OBJECTIVES

The CROSS trial established neoadjuvant chemoradiation followed by surgery (nCRT-S) as superior to surgery alone (S) for locally advanced esophageal cancer (EC). However, because patients above 75 years of age were excluded, this comparison cannot be extrapolated to older patients. This study of a large, contemporary national database evaluated practice patterns in elderly patients ineligible for CROSS, and analyzed overall survival (OS) between nCRT+S, S, and definitive CRT (dCRT).

MATERIALS AND METHODS

The National Cancer Data Base was queried for EC patients with cT1N1M0/T2-3N0-1M0 EC (per the CROSS trial) but 76 years and above of age. Multivariable logistic regression ascertained factors associated with nCRT+S (vs. S). Kaplan-Meier analysis evaluated OS; Cox multivariate analysis determined variables associated with OS. Propensity matching aimed to address group imbalances and indication biases.

RESULTS

Of 4099 total patients, 594 (14%) underwent nCRT+S, 494 (12%) underwent S, and 3011 (73%) underwent dCRT. Since 2010, trimodality management has risen, corresponding to declines in S and dCRT. Median OS in the respective groups were 26.7, 20.3, and 17.8 months (P<0.05). Following propensity matching, there was a trend towards higher OS with nCRT-S over S (P=0.077); dCRT showed poorer OS than nCRT-S (P<0.001) but was equivalent to S (P=0.669). Before and following matching, nCRT-S experienced equivalent 30- and 90-day mortality as S (P>0.05), with lower 30-day readmission and postoperative hospital stay (P<0.05).

CONCLUSIONS

Although most older patients not meeting CROSS criteria undergo dCRT, utilization of trimodality therapy is rising. Despite the trend towards higher OS with trimodality therapy without poorer postoperative outcomes, careful patient selection continues to be essential in this population.

Complications and adverse events of plaque brachytherapy for ocular melanoma

Plaque brachytherapy is a well-accepted modality to manage selected cases of ocular melanoma. Although this modality provides validated oncologic and quality of life benefits, severe complications and adverse events can occur. This article reviews complications and adverse events of plaque brachytherapy, including scleral necrosis, strabismus, cataract, glaucoma, and retinopathies as well as management of these conditions. For practicing oncologists and ophthalmologists, these complications are important to understand, identify, and treat. Additionally, an understanding of common complications of brachytherapy should influence the decision of pursuing it as a treatment option.

Vitamin D receptors (VDR), hydroxylases CYP27B1 and CYP24A1 and retinoid-related orphan receptors (ROR) level in human uveal tract and ocular melanoma with different melanization levels

In recent years, a significant number of studies have investigated the preventive role of vitamin D in a number of different neoplasms. In this study, we analyze various components of the vitamin D signaling pathways in the human uveal tract and uveal melanoma, including analysis of the expression of vitamin D receptors (VDR), the activating and inactivating hydroxylases, respectively, CYP27B1 and CYP24A1, and the retinoic acid-related orphan receptors (ROR) α (RORα) and γ (RORγ) in these tissues. We further analyzed the expression of VDR, CYP27B1, CYP24A1, and ROR in relation to melanin levels, clinical stage and prognosis. Our study indicated that the uveal melanoma melanin level inversely correlated with VDR expression. We further showed that vitamin D is metabolized in uveal melanoma. This is significant because until now there has been no paper published, that would describe presence of VDR, hydroxylases CYP27B1 and CYP24A1, and RORα and RORγ in the human uveal tract and uveal melanomas. The outcomes of our research can contribute to the development of new diagnostic and therapeutic methods in uveal tract disorders, especially in uveal melanoma. The presented associations between vitamin D signaling elements and uveal melanoma in comparison to uveal tract encourage future clinical research with larger patients’ population.

Increased elasticity of melanoma cells after low-LET proton beam due to actin cytoskeleton rearrangements

Cellular response to non-lethal radiation stress include perturbations in DNA repair, angiogenesis, migration, and adhesion, among others. Low-LET proton beam radiation has been shown to induce somewhat different biological response than photon radiation. For example, we have shown that non-lethal doses of proton beam radiation inhibited migration of cells and that this effect persisted long-term. Here, we have examined cellular elasticity and actin cytoskeleton organization in BLM cutaneous melanoma and Mel270 uveal melanoma cells. Proton beam radiation increased cellular elasticity to a greater extent than X-rays and both types of radiation induced changes in actin cytoskeleton organization. Vimentin level increased in BLM cells after both types of radiation. Our data show that cell elasticity increased substantially after low-LET proton beam and persisted long after radiation. This may have significant consequences for the migratory properties of melanoma cells, as well as for the cell susceptibility to therapy.

Proton beam therapy for cancer in the era of precision medicine

Precision radiotherapy, which accurately delivers the dose on a tumor and confers little or no irradiation to the surrounding normal tissue and organs, results in maximum tumor control and decreases the toxicity to the utmost extent. Proton beam therapy (PBT) provides superior dose distributions and has a dosimetric advantage over photon beam therapy. Initially, the clinical practice and study of proton beam therapy focused on ocular tumor, skull base, paraspinal tumors (chondrosarcoma and chordoma), and unresectable sarcomas, which responded poorly when treated with photon radiotherapy. Then, it is widely regarded as an ideal mode for reirradiation and pediatrics due to reducing unwanted side effects by lessening the dose to normal tissue. During the past decade, the application of PBT has been rapidly increasing worldwide and gradually expanding for the treatment of various malignancies. However, to date, the role of PBT in clinical settings is still controversial, and there are considerable challenges in its application. We systematically review the latest advances of PBT and the challenges for patient treatment in the era of precision medicine.

Dosimetric Comparison of Proton Radiation Therapy, Volumetric Modulated Arc Therapy, and Three-Dimensional Conformal Radiotherapy Based on Intracranial Tumor Location

(1) Background: Selecting patients that will benefit the most from proton radiotherapy (PRT) is of major importance. This study sought to assess dose reductions to numerous organs-at-risk (OARs) with PRT, as compared to three-dimensional conformal radiotherapy (3DCRT) and volumetric-modulated arc therapy (VMAT), as a function of tumor location. (2) Materials/Methods: Patients with intracranial neoplasms (all treated with PRT) were stratified into five location-based groups (frontal, suprasellar, temporal, parietal, posterior cranial fossa; n = 10 per group). Each patient was re-planned for 3DCRT and intensity-modulated radiotherapy (IMRT) using similar methodology, including the originally planned target and organ-at-risk (OAR) dose constraints. (3) Results: In parietal tumors, PRT showed the most pronounced dose reductions. PRT lowered doses to nearly every OAR, most notably the optical system and several contralateral structures (subventricular zone, thalamus, hippocampus). For frontal lobe cases, the greatest relative dose reductions in mean dose (D_mean) with PRT were to the infratentorial normal brain, contralateral hippocampus, brainstem, pituitary gland and contralateral optic nerve. For suprasellar lesions, PRT afforded the greatest relative D_mean reductions to the infratentorial brain, supratentorial brain, and the whole brain. Similar results could be observed in temporal and posterior cranial fossa disease. (4) Conclusions: The effectiveness and degree of PRT dose-sparing to various OARs depends on intracranial tumor location. These data will help to refine selection of patients receiving PRT, cost-effectiveness, and future clinical toxicity assessment.

Linear accelerator-based stereotactic fractionated photon radiotherapy as an eye-conserving treatment for uveal melanoma

Background

The purpose of this retrospective analysis is to analyze clinical outcome, visual acuity and enucleation rates after linear accelerator-based stereotactic fractionated photon radiotherapy for primary uveal melanoma.

Methods

Twenty-four patients with primary uveal melanoma treated at the Department of Radiation and Oncology of the University Hospital Heidelberg between 1991 and 2015 were analyzed regarding survival and treatment-related toxicity including eye- and sight-preservation.

Results

Photon radiotherapy (RT) offered good overall local control rates with a local progression-free survival (LPFS) of 82% after 5 years and a median LPFS of 5.5 years at a median follow-up time of 5.2 years. Gender had a significant impact on LPFS yielding a mean LPFS of 8.1 years for women and 8.7 years for men (p = 0.04). Of all local progressions, 80% occurred within the first 5 years after RT. In one case, enucleation as final therapy option was necessary. Enucleation-free survival (EFS) was related to the radiotherapy dose (p < 0.0001). Thus, higher prescribed doses led to a significantly higher enucleation rate. T-stage had no significant impact on EFS, but affected the enucleation rate (p = 0.01). The overall survival (OS) rate was 100% after 2 years and 70% after 5 years with a median OS of 5.75 years. Age (p = 0.046), T stage (p = 0.019), local control rate (p = 0.041) and the time between diagnosis and the first radiation session (p = 0.01) had a significant effect on OS. Applied biologically effective dose (BED) did not significantly influence OS or PFS. A 2-year sight preservation rate of 75% could be achieved. In all patients, irradiation could be applied safely without any interruptions due to side effects. Six significant late toxicities with consequential blindness could be observed, making a secondary enucleation necessary in four patients. An impairment of visual acuity due to chronic optic nerve atrophy was identified in five patients within 2 years after treatment.

Conclusions

Linear accelerator-based stereotactic fractionated photon radiotherapy is an effective method in the treatment of uveal melanoma with excellent local control rates and a 2-year vision retention rate comparable to brachytherapy (BRT) or proton beam radiotherapy, even available in small centers and easy to implement. Interdisciplinary decision making is necessary to guarantee best treatment for every patient.

Proton Beam Therapy for Bronchogenic Adenoid Cystic Carcinoma: Dosimetry, Toxicities, and Outcomes

Purpose

Bronchogenicadenoid cystic carcinoma (ACC) is a rare malignancy particularly challenging to irradiate, largely owing to anatomic location and associated toxicities. Proton beam therapy (PBT) can reduce doses to nearby organs at risk, but only one case report has been published detailing PBT for this neoplasm.

Patients and Methods

This study was an institutional review board-approved retrospective chart review of all patients at one institution with bronchogenic ACC treated with PBT. Toxicities were assessed per Common Toxicity Criteria for Adverse Events, version 4.0.

Results

Five patients, median age 67 years (range = 40-97 years), were all symptomatic before PBT. Two patients were debulked before PBT, which was delivered at a median 66.6 Gy (RBE) (range, 57.5-80 Gy (RBE)). Two patients received concurrent platinum-based chemotherapy. Symptoms improved in all patients. Acute toxicities included the following: grade 1 fatigue (n = 3), grade 1 dermatitis (n = 2), grade 1 esophagitis (n = 1), grade 2 fatigue (n = 1), grade 2 dermatitis (n = 1), grade 2 esophagitis (n = 2). There was one case of late radiation fibrosis causing bronchial stenosis and requiring a stent, and another of late grade 1 dysphagia. All grade 2 toxicities occurred in patients receiving concurrent chemoradiotherapy. At median follow-up of 10 months (range = 5-47 months), no patient experienced tumor recurrence and none had symptoms impairing daily functioning or quality of life. Although statistically nonsignificant owing to low sample sizes, dosimetric data revealed that PBT numerically reduced doses, most notably to the heart and to low-dose volumes of the lung.

Conclusions

This is the largest series to date evaluating PBT for bronchogenic ACC. PBT is associated with low rates of acute and late toxicities and excellent early local control.

Transplantable Melanomas in Hamsters and Gerbils as Models for Human Melanoma. Sensitization in Melanoma Radiotherapy-From Animal Models to Clinical Trials

The focus of the present review is to investigate the role of melanin in the radioprotection of melanoma and attempts to sensitize tumors to radiation by inhibiting melanogenesis. Early studies showed radical scavenging, oxygen consumption and adsorption as mechanisms of melanin radioprotection. Experimental models of melanoma in hamsters and in gerbils are described as well as their use in biochemical and radiobiological studies, including a spontaneously metastasizing ocular model. Some results from in vitro studies on the inhibition of melanogenesis are presented as well as radio-chelation therapy in experimental and clinical settings. In contrast to cutaneous melanoma, uveal melanoma is very successfully treated with radiation, both using photon and proton beams. We point out that the presence or lack of melanin pigmentation should be considered, when choosing therapeutic options, and that both the experimental and clinical data suggest that melanin could be a target for radiosensitizing melanoma cells to increase efficacy of radiotherapy against melanoma.

Optimizing radiosurgery with photons for ocular melanoma

BACKGROUND AND PURPOSE

Photon radiotherapy has been established for the treatment of ocular melanoma (OM). Here we investigate the planning qualities of two different planning approaches, a combination of dynamic conformal arcs (DCA) complemented with multiple non-coplanar static intensity-modulated (IMRT) fields (DCA-IMRT), and volumetric modulated arc therapy (VMAT) in combination with automated planning (AP).

MATERIALS AND METHODS

Thirteen consecutive patients treated for ocular melanoma with curative intent on a Linac-based radiosurgery system were analyzed. Fractionated stereotactic radiosurgery (fSRS) was applied using 50 Gy in 5 fractions using the combination of DCA-IMRT. Plans were reviewed and the thirteen cases were compared to plans obtained with optimized automated VMAT based on a set of 28 distinct patients treated with DCA-IMRT who were selected to generate the AP model for the prediction of dose volume constraints.

RESULTS

Overall, plan quality of DCA-IMRT was superior to AP with VMAT. PTV coverage did not exceed 107% in any case treated with DCA-IMRT, compared to seven patients with VMAT. The median PTV covered by >95% was 98.3% (91.9%-99.7%) with DCA-IMRT, compared to 95.1% (91.5%-97.9%) (p < 0.01) with VMAT. The median mean dose delivered to the treated eye was 22.4 Gy (12.3 Gy-33.3 Gy) with DCA-IMRT compared to 27.2 Gy (15.5 Gy-33.7 Gy) (p < 0.01). Dose to the ipsilateral lacrimal gland and the ipsilateral optic nerve were comparable for DCA-IMRT and VMAT, however, the dose to the lens was lower with DCA-IMRT compared to VMAT.

CONCLUSIONS

The combination of multiple arcs complemented with multiple IMRT fields sets the gold standard for fSRS of ocular melanoma for photon therapy.

Proton therapy for small cell lung cancer

The prognosis of limited-stage small cell lung cancer (LS-SCLC) continues to improve and is now roughly comparable to that of locally advanced non-small cell lung cancer (NSCLC). This shift, taken together with the decreased toxicities of modern radiotherapy (RT) for LS-SCLC compared with those reported in historical trials, necessitates further evaluation of whether proton beam therapy (PBT) could further reduce both acute and late toxicities for patients receiving concurrent chemoradiotherapy for LS-SCLC. These notions are discussed theoretically, with an emphasis on cardiac events. This is followed by a review of the published evidence to date demonstrating improved dosimetry with PBT over intensity-modulated RT and encouraging safety and efficacy profiles seen in early clinical reports. In addition to covering technical aspects of PBT for LS-SCLC such as intensity-modulated PBT, image-guidance for PBT, and adaptive planning, this review also discusses the need for increased data on intensity-modulated PBT for LS-SCLC, economic and quality of life analyses for future PBT SCLC studies, careful categorization of cardiac events in these patients, and the role for immunotherapy combined with photon- or proton-based RT for LS-SCLC.

Quality of Life and Patient-Reported Outcomes Following Proton Radiation Therapy: A Systematic Review

Background

As costs of cancer care rise, the importance of documenting value in oncology increases. Proton beam radiotherapy (PBT) has the potential to reduce toxicities in cancer patients, but is relatively expensive and unproven. Evaluating quality of life (QOL) and patient-reported outcomes (PROs) is essential to establishing PBT's "value" in oncologic therapy. The goal of this systematic review was to assess QOL and PROs in patients treated with PBT.

Methods

Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-guided systematic searches were conducted. The PubMed search engine was the primary data source, along with publications found from references of selected articles, and articles known to the authors published through 2017. Seventeen original investigations were found to have sufficient focus and relevance to be incorporated into the systematic review.

Results

Studies of skull base (n = 1), brain (n = 1), head/neck (n = 1), lung (n = 1), breast (n = 2), prostate (n = 8), and pediatric (n = 3) malignancies treated with PBT that met eligibility criteria were included. QOL did not deteriorate during PBT for skull base and after PBT for brain tumors, respectively. PROs were higher for PBT than photon-based radiotherapy for both head/neck and lung cancer. Patient-reported breast cosmesis was appropriate after PBT and comparable to photon modalities. PBT in various settings of prostate cancer displayed an expected post-therapy decline; one study showed improved PROs (rectal urgency, bowel frequency) for PBT, and two others showed PROs/QOL comparable with other modalities. Pediatric studies demonstrated improvements in QOL during therapy, with additional increases thereafter.

Conclusions

Based on limited data, PBT provides favorable QOL/PRO profiles for select brain, head/neck, lung, and pediatric cancers; measures for prostate and breast cancers were more modest. These results have implications for cost-effective cancer care and prudently designed QOL evaluation in ongoing trials, which are discussed. Future data could substantially change the conclusions of this review.

Utilization of neoadjuvant intensity-modulated radiation therapy and proton beam therapy for esophageal cancer in the United States

Background

Randomized esophageal cancer (EC) trials have utilized two- or three-dimensional conformal radiotherapy (3DCRT). Advanced radiotherapy (RT) techniques [(ARTs): intensity-modulated radiotherapy (IMRT) and proton beam therapy (PBT)] may have benefits, but are relatively unproven. This is the first study to date evaluating utilization of ARTs versus 3DCRT in the trimodality setting in the United States.

Methods

The National Cancer Data Base (NCDB) was queried (2004-2013) for newly-diagnosed cT1b-T4bN0/N+M0 EC receiving neoadjuvant CRT followed by esophagectomy. The primary objective was to assess temporal trends, with multivariable logistic regression analysis assessing factors predictive of receiving ARTs. Secondarily, Kaplan-Meier analysis evaluated overall survival (OS), Cox proportional hazards modeling determined variables associated with OS, and postoperative complications were compared between cohorts.

Results

Altogether, 3,138 patients met criteria; 1,398 (45%) received 3DCRT, and 1,740 (55%) received ARTs (99% IMRT, 1% PBT). Temporally, utilization of ARTs is steadily rising in the United States, from 20% in 2004 to 69% in 2013, corresponding with a progressive decrease in utilization of 3DCRT. ARTs were more often delivered with advancing age, squamous cell histology, N2+ disease, and at academic centers (P<0.05 for all). Centers in the Southwest were more likely to use ARTs, and those in the Midwest least likely (P<0.05 for both). As expected, there were no OS differences (P=0.8477); there were also no differences in postoperative events (P>0.05 for all). Treatment at an academic center independently correlated with improved OS (P<0.001).

Conclusions

Utilization of ARTs (IMRT in the vast majority) is steadily rising in the United States; 3DCRT is now used in a minority of patients. This has implications for payers and insurance coverage. ART use is impacted by not only age and disease factors, but also regional and facility differences. Treatment at an academic facility independently correlated with higher survival, which has implications for patient counseling.

Recent advances in uveal melanoma treatment

Uveal melanoma (UM) is the most common primary intraocular malignancy in adults. Recent advances in the understanding of molecular characteristics helped to determine which tumors are most likely to progress. About 50% of patients carrying genetic alterations such as chromosomal aberrations and mutations are at significant risk for metastatic disease of which the majority will succumb to UM within few months. Currently, there is no effective treatment for metastatic uveal melanoma, and we hope this review will encourage researchers and clinicians to work to find a better standard of care. In this article we provide a comprehensive overview of the molecular framework of UM, highlighting the most common mutations involved in this kind of cancer. It also covers the most recent treatments from basic research to clinical trials, including small molecules, nucleic acids or immunotherapy, among others. It is intended to serve as a key reference for clinicians and researchers working in this field.

Adjuvant Ab Interno Tumor Treatment After Proton Beam Irradiation

PURPOSE

This study was performed to show long-term outcomes concerning globe preservation in uveal melanoma patients after proton beam therapy with the main focus on outcomes according to different adjuvant ab interno surgical procedures.

DESIGN

Retrospective cohort study.

METHODS

All patients treated with primary proton beam therapy for choroidal or ciliary body melanoma between June 1998 and June 2015 were included.

RESULTS

A total of 2499 patients underwent primary proton beam therapy, with local tumor control and globe preservation rates of 95.9% and 94.8% after 5 years, respectively. A total of 110 (4.4%) patients required secondary enucleation. Unresponsive neovascular glaucoma was the leading cause of secondary enucleation in 78 of the 2499 patients (3.1%). The 5-year enucleation-free survival rate was 94.8% in the endoresection group, 94.3% in the endodrainage group, and 93.5% in the comparator group. The log-rank test showed P = .014 (comparator group vs endoresection group) and P = .06 (comparator group vs endodrainage-vitrectomy group). Patients treated with endoresection or endodrainage-vitrectomy developed less radiation retinopathy (30.5% and 37.4% after 5 years, P = .001 and P = .048 [Kaplan-Meier], respectively) and less neovascular glaucoma (11.6% and 21.3% after 5 years, P = .001 and P = .01 [Kaplan-Meier], respectively) compared with the comparator group (52.3% radiation retinopathy and 57.8% neovascular glaucoma after 5 years).

CONCLUSION

This study suggests that in larger tumors the enucleation and neovascular glaucoma rates might be reduced by adjuvant surgical procedures. Although endoresection is the most promising adjuvant treatment option, the endodrainage-vitrectomy is recommended in patients who are ineligible for endoresection.

Proton radiotherapy for gynecologic neoplasms

BACKGROUND

Proton beam therapy (PBT) is increasingly being used globally to treat a variety of malignancies. This is the first review assessing PBT for gynecologic neoplasms. Dose distribution to organs-at-risk (OARs), particularly bone marrow (BM), is addressed. Clinical outcomes and toxicity data are detailed.

MATERIAL AND METHODS

Systematic searches of PubMed, EMBASE, abstracts from meetings of the American Society for Radiation Oncology, Particle Therapy Co-Operative Group, and American Society of Clinical Oncology were conducted for publications. There were no restrictions on publication dates. Sixteen original investigations were identified and analyzed for this review.

RESULTS

The available evidence for PBT in treating gynecologic cancers is of both low quantity and quality. The most studied scenarios for PBT include treatment of para-aortic lymph nodes, re-irradiation, and as an alternative to brachytherapy, and these also represent indications with the greatest opportunity for demonstrating as yet unproven toxicity reductions. Dosimetric studies have shown significantly decreased dose to OARs, such as the rectum, bladder, bowel, kidneys, BM, and femoral heads. This dose reduction to OARs with PBT is more pronounced within the low-dose volumes than the higher dose volumes, which radiobiologically could be expected to lower second malignancy rates. Clinical data, though no level 1 evidence, show appropriate stage-specific tumor control and outcomes with PBT treatment, along with low toxicity rates.

CONCLUSION

The existing data, albeit limited, warrant and can help guide larger scale and higher quality studies addressing whether PBT could provide clinically meaningful differences in toxicities and outcomes in women with gynecologic neoplasms.

Uveal melanoma: quantitative evaluation of diffusion-weighted MR imaging in the response assessment after proton-beam therapy, long-term follow-up

PURPOSE

The purpose of this prospective study was to investigate the proton-beam-induced changes in apparent diffusion coefficient (ADC) values of ocular melanoma treated with proton-beam therapy (PBT) in patients undergoing long-term magnetic resonance imaging (MRI) follow-up and to assess whether variations in ADC constitute a reliable biomarker for predicting and detecting the response of ocular melanoma to PBT.

METHODS

Seventeen patients with ocular melanoma treated with PBT were enrolled. All patients underwent conventional MRI and diffusion-weighted imaging (DWI) at baseline and 1, 3, 6, and 18 months after the beginning of therapy. Tumor volumes and ADC values of ocular lesions were measured at each examination. Tumor volumes and mean ADC measurements of the five examination series were compared; correlation of ADC values and tumor regression was estimated.

RESULTS

Mean ADC values of ocular melanomas significantly increased already 1 month after therapy whereas tumor volume significantly decreased only 6 months after therapy. Pretreatment ADC value of ocular melanomas and early change in ADC value 1 month after therapy significantly correlated with tumor regression.

CONCLUSIONS

In ocular melanoma treated with PBT, ADC variations precede volume changes. Both pretreatment ADC and early change in ADC value may predict treatment response, thus expanding the role of DWI from diagnostic to prognostic.

Clinical outcomes and toxicities of proton radiotherapy for gastrointestinal neoplasms: a systematic review

BACKGROUND

Proton beam radiotherapy (PBT) is frequently shown to be dosimetrically superior to photon radiotherapy (RT), though supporting data for clinical benefit are severely limited. Because of the potential for toxicity reduction in gastrointestinal (GI) malignancies, we systematically reviewed the literature on clinical outcomes (survival/toxicity) of PBT.

METHODS

A systematic search of PubMed, EMBASE, abstracts from meetings of the American Society for Radiation Oncology, Particle Therapy Co-Operative Group, and American Society of Clinical Oncology was conducted for publications from 2000-2015. Thirty-eight original investigations were analyzed.

RESULTS

Although results of PBT are not directly comparable to historical data, outcomes roughly mirror previous data, generally with reduced toxicities for PBT in some neoplasms. For esophageal cancer, PBT is associated with reduced toxicities, postoperative complications, and hospital stay as compared to photon radiation, while achieving comparable local control (LC) and overall survival (OS). In pancreatic cancer, numerical survival for resected/unresected cases is also similar to existing photon data, whereas grade ≥3 nausea/emesis and post-operative complications are numerically lower than those reported with photon RT. The strongest data in support of PBT for HCC comes from phase II trials demonstrating very low toxicities, and a phase III trial of PBT versus transarterial chemoembolization demonstrating trends towards improved LC and progression-free survival (PFS) with PBT, along with fewer post-treatment hospitalizations. Survival and toxicity data for cholangiocarcinoma, liver metastases, and retroperitoneal sarcoma are also roughly equivalent to historical photon controls. There are two small reports for gastric cancer and three for anorectal cancer; these are not addressed further.

CONCLUSIONS

Limited quality (and quantity) of data hamper direct comparisons and conclusions. However, the available data, despite the inherent caveats and limitations, suggest that PBT offers the potential to achieve significant reduction in treatment-related toxicities without compromising survival or LC for multiple GI malignancies. Several randomized comparative trials are underway that will provide more definitive answers.

Effect of Akimbo versus Raised Arm Positioning on Breast and Cardiopulmonary Dosimetry in Pediatric Hodgkin Lymphoma

Purpose

In pediatric Hodgkin lymphoma (HL), radiotherapy (RT)-related late toxicities are a prime concern during treatment planning. This is the first study to examine whether arm positioning (raised versus akimbo) result in differential cardiopulmonary and breast doses in patients undergoing mediastinal RT.

Methods

Two treatment plans were made for each patient (akimbo/arms raised); treatment was per Children’s Oncology Group AHOD0031 protocol, including AP/PA fields. The anterior midline T6–T7 disk space was used as an anatomic reference of “midline.” Heart/lungs were contoured for each setup. For females, breasts were also contoured and nipple positions identified. Volumetric centers of contoured organs were defined and three-dimensional distances from “midline” were computed. Analyzed dosimetric parameters included V5 (volume receiving ≥5 Gy), V10, V15, V20, and mean dose. Statistics were performed using the Mann–Whitney test.

Results

Fifteen (6 females, 9 males) pediatric HL patients treated with mediastinal RT were analyzed. The median lateral distance from the breast center/nipple to “midline” with arms akimbo was larger than that with arms raised (8.6 vs. 7.7 cm left breast, p = 0.04; 10.7 vs. 9.2 cm left nipple, p = 0.04; 8.7 vs. 7.0 cm right breast, p = 0.004; 9.9 vs. 7.9 cm right nipple, p = 0.007). Raised arm position was associated with a median 2.8/3.0 cm decrease in breast/nipple separation, respectively. There were no significant differences in craniocaudal breast/nipple position based on arm positioning (p > 0.05). Increasing breast volume was correlated with larger arm position-related changes in breast/nipple separation (r = 0.74, p = 0.06/r = 0.85, p = 0.02). Akimbo positioning lowered median breast V5, V10, V15, and mean dose (p < 0.05), with no differences observed in patients with both mediastinal and axillary disease for any parameters (p > 0.05). Arm position had no significant effect on cardiopulmonary doses.

Conclusion

Akimbo arm positioning may be advantageous to decrease breast doses in female pediatric HL patients undergoing mediastinal RT, especially in the absence of axillary disease.