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

Temporal Evolution and Diagnostic Diversification of Patients Receiving Proton Therapy in the United States: A Ten-Year Trend Analysis (2012 to 2021) From the National Association for Proton Therapy

PURPOSE

The National Association for Proton Therapy conducted 8 surveys of all operational United States proton centers (2012-2021) and analyzed the patients treated, diagnoses, and treatment complexity to evaluate trends and diversification of patients receiving proton therapy.

METHODS AND MATERIALS

Detailed surveys were sent in 2015, which requested data from 2012 to 2014, and then annually thereafter to active proton centers in the United States. The numbers of patient treated at each center for the preceding calendar year(s) were collated for tumors in the following categories: central nervous system, intraocular, pituitary, skull base/skeleton, head/neck, lung, retroperitoneal/soft tissue sarcoma, pediatric (solid tumors in children of age ≤18), gastrointestinal tract, urinary tract, female pelvic, prostate, breast, and "other." Complexity levels were assessed using Current Procedural Terminology codes 77520-77525.

RESULTS

Survey response rates were excellent (100% in 2015 to 94.9% in 2021); additional publicly available information provided near-complete information on all centers. Trend comparisons between 2012 and 2021 showed that the total annual number of patients treated with protons gradually increased from 5377 to 15,829. The largest numeric increases were for head/neck (316 to 2303; 7.3-fold), breast (93 to 1452; 15.6-fold), and gastrointestinal tumors (170 to 1259; 7.4-fold). Patient numbers also increased significantly for central nervous system (598 to 1743; 2.9-fold), pediatric (685 to 1870; 2.7-fold), and skull base tumors (179 to 514; 2.9-fold). For prostate cancer, the percentage of proton-treated patients decreased from 43.4% to 25.0% of the total. Simple compensated treatments decreased from 43% in 2012 to 7% in 2021, whereas intermediate complexity treatments increased from 45% to 73%.

CONCLUSIONS

The number of patients treated with protons is gradually increasing, with a substantial proportionate decline in patients with prostate cancer receiving proton therapy. The number of patients treated for "commonly accepted" indications for protons (eg, pediatric, central nervous system, and skull base tumors) is gradually increasing. Greater proportional increases were observed for breast, lung, head/neck, and gastrointestinal tumors. Treatment complexity is gradually increasing over time.

Choosing the right questions - A systematic review of patient reported outcome measures used in radiotherapy and proton beam therapy

The implementation of PROMs into clinical practice has been shown to improve quality of care. This systematic review aims to identify which PROMs are suitable for implementation within routine clinical practice in a radiotherapy or PBT service.The bibliographic databases MEDLINE, EMBASE and EMCARE were searched. Articles published between 1st January 2008 to 1st June 2023, that reported PROMs being utilised as an outcome measure were included. Inclusion criteria also included being written in English, involving human patients, aged 16 and above, receiving external beam radiotherapy or PBT for six defined tumour sites. PROMs identified within the included articles were subjected to quality assessment using the COSMIN reporting guidelines. Results are reported as per PRISMA guidelines. A total of 268 studies were identified in the search, of which 52 fulfilled the inclusion criteria. The use of 39 different PROMs was reported. The PROMs identified were mostly tumour or site-specific quality of life (n = 23) measures but also included generic cancer (n = 3), health-related quality-of-life (n = 6), and symptom specific (n = 7) measures.None of the PROMs identified received a high GRADE score for good content. There were 13 PROMs that received a moderate GRADE score. The remaining PROMs either had limited evidence of development and validation within the patient cohorts investigated, or lacked relevance or comprehensiveness needed for routine PROMs collection in a radiotherapy or PBT service.This review highlights that there are a wide variety of PROMs being utilised within radiotherapy research, but most lack specificity to radiotherapy side-effects. There is a risk that by using non-specific PROMs in clinical practice, patients might not receive the supportive care that they need.

Meta analysis of the second course of radiotherapy for recurrent esophageal cancer1

BACKGROUND

How to improve efficacy and reduce side effects in treating recurrent esophageal cancer by applying the second course of radiotherapy alone and its combination with chemotherapy has been attracting broad research interest.

OBJECTIVE

This review paper aims to systematically evaluate efficacy and side effects of applying the second course of anterograde radiotherapy alone and its combination with chemotherapy in treating recurrent esophageal cancer.

METHODS

First, the relevant research papers are retrieved from PubMed, CNKI and Wanfang databases. Next, Redman 5.3 software is used to calculate the relative risk and 95% confidence interval to evaluate the efficacy and adverse reactions of applying the single-stage radiotherapy with and without combining single/multi dose chemotherapy to treat recurrent esophageal cancer. Then, a meta data analysis is applied to examine the effectiveness and side effects of radiation alone and re-course radiotherapy plus chemotherapy in treating esophageal cancer recurrence after the first radiotherapy.

RESULTS

Fifteen papers are retrieved, which included 956 patients. Among them, 476 patients received radiotherapy combined with single drug/multi drug chemotherapy (observation) and others received only radiotherapy (control). Data analysis results show that the incidence of radiation induced lung injury and bone marrow suppression is high in the observation group. Subgroup analysis also shows the higher effective rate or one-year overall survival rate of patients treated with the second course radiotherapy combined with single drug chemotherapy.

CONCLUSION

The meta-analysis result demonstrates that combining the second course of radiotherapy with single-drug chemotherapy has advantages in treating recurrent esophageal cancer with the manageable side effects. However, due to insufficient data, it is not possible to conduct the further subgroup analysis comparing the side effects of restorative radiation with the combined chemotherapy using between a single drug and multiple drugs.

Proton beam therapy in paediatric cancer: Anticipating the opening of the Australian Bragg Centre for Proton Therapy and Research

Proton Beam Therapy (PBT) has the potential to improve paediatric cancer care by reducing radiation exposure and thus long-term toxicities. Ethical concerns and debates surrounding the treatment, such as eligibility and accessibility, are ongoing in Australia. The Australian Bragg Centre for Proton Therapy and Research (ABCPTR) (named after Sir William Henry Bragg who described the Bragg peak in his laboratory at the University of Adelaide in 1903) aims to increase access to PBT in Australasia and offer a patient-centred care approach. Research is underway to assess PBT's safety and cost-effectiveness, using tools including Normal Tissue Complication Probability (NTCP) models. Collaborative efforts are focused on developing tailored survivorship clinics to enhance patient follow-up and quality of life. With the anticipated opening of the ABCPTR, Australia is preparing to take a significant step in radiation oncology, offering new research opportunities and creating a publicly funded treatment centre. The initiative aims to balance treatment efficacy with patient care, setting the stage for a future in which radiation therapy will reduce long-term side effects compared to the current standard of care. The implementation of PBT in Australia represents a complex and promising approach to paediatric oncology. This article provides an overview of the current landscape, highlighting the potential benefits and challenges of a treatment that could redefine the quality of survivorship and contribute to global research and best clinical practice.

Advances and Challenges in Conducting Clinical Trials With Proton Beam Therapy

Advances in proton therapy have garnered much attention and speculation in recent years as the indications for proton therapy have grown beyond pediatric, prostate, spine, and ocular tumors. To achieve and maintain consistent access to this cancer treatment and to ensure the future viability and availability of proton centers in the United States, a call for evidence has been heard and answered by proton radiation oncologists. Answers provided in this review include the evolution of proton therapy research, rationale for proton clinical trial design, challenges in and barriers to the conduct of proton therapy research, and other unique considerations for the study of proton therapy.

Proton Therapy in the Adolescent and Young Adult Population

BACKGROUND

Adolescent and young adult cancer patients are at high risk of developing radiation-associated side effects after treatment. Proton beam radiation therapy might reduce the risk of these side effects for this population without compromising treatment efficacy.

METHODS

We review the current literature describing the utility of proton beam radiation therapy in the treatment of central nervous system tumors, sarcomas, breast cancer and Hodgkin lymphoma for the adolescent and young adult cancer population.

RESULTS

Proton beam radiation therapy has utility for the treatment of certain cancers in the young adult population. Preliminary data suggest reduced radiation dose to normal tissues, which might reduce radiation-associated toxicities. Research is ongoing to further establish the role of proton therapy in this population.

CONCLUSION

This report highlights the potential utility of proton beam radiation for certain adolescent young adult cancers, especially with reducing radiation doses to organs at risk and thereby potentially lowering risks of certain treatment-associated toxicities.

Quality of Life and Patient-Reported Outcomes Following Proton Therapy for Oropharyngeal Carcinoma: A Systematic Review

BACKGROUND

Complex anatomy surrounding the oropharynx makes proton therapy (PT), especially intensity-modulated PT (IMPT), a potentially attractive option due to its ability to reduce the volume of irradiated healthy tissues. Dosimetric improvement may not translate to clinically relevant benefits. As outcome data are emerging, we aimed to evaluate the evidence of the quality of life (QOL) and patient-reported outcomes (PROs) following PT for oropharyngeal carcinoma (OC).

MATERIALS AND METHODS

We searched PubMed and Scopus electronic databases (date: 15 February 2023) to identify original studies on QOL and PROs following PT for OC. We employed a fluid strategy in the search strategy by tracking citations of the initially selected studies. Reports were extracted for information on demographics, main results, and clinical and dose factor correlates. Quality assessment was performed using the NIH's Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. The PRISMA guidelines were followed in the preparation of this report.

RESULTS

Seven reports were selected, including one from a recently published paper captured from citation tracking. Five compared PT and photon-based therapy, although none were randomized controlled trials. Most endpoints with significant differences favored PT, including xerostomia, cough, need for nutritional supplements, dysgeusia, food taste, appetite, and general symptoms. However, some endpoints favored photon-based therapy (sexual symptoms) or showed no significant difference (e.g., fatigue, pain, sleep, mouth sores). The PROs and QOL improve following PT but do not appear to return to baseline.

CONCLUSION

Evidence suggests that PT causes less QOL and PRO deterioration than photon-based therapy. Biases due to the non-randomized study design remain obstacles to a firm conclusion. Whether or not PT is cost-effective should be the subject of further investigation.

Evaluating patient reported outcomes and experiences in a novel proton beam clinic - challenges, activities, and outcomes of the ProtonCare project

BACKGROUND

The ProtonCare Study Group (PCSG) was formed with the purpose to develop and implement a framework for evaluation of proton beam therapy (PBT) and the related care at a novel clinic (Skandionkliniken), based on patient reported data.

METHOD

A logic model framework was used to describe the process of development and implementation of a structured plan for evaluation of PBT for all diagnoses based on patient reported data. After the mission for the project was determined, meetings with networks and stakeholders were facilitated by PCSG to identify assumptions, resources, challenges, activities, outputs, outcomes, and outcome indicators.

RESULT

This paper presents the challenges and accomplishments PCSG made so far. We describe required resources, activities, and accomplished results. The long-term outcomes that were outlined as a result of the process are two; 1) Improved knowledge about health outcomes of patients that are considered for PBT and 2) The findings will serve as a base for clinical decisions when patients are referred for PBT.

CONCLUSION

Using the logical model framework proved useful in planning and managing the ProtonCare project. As a result, the work of PCSG has so far resulted in long-lasting outcomes that creates a base for future evaluation of patients' perspective in radiotherapy treatment in general and in PBT especially. Our experiences can be useful for other research groups facing similar challenges. Continuing research on patients´ perspective is a central part in ongoing and future research. Collaboration, cooperation, and coordination between research groups/networks from different disciplines are a significant part of the work aiming to determine the more precise role of PBT in future treatment options.

Proton Beam Therapy for Esophageal Cancer

Simple Summary

Early-stage esophageal cancer is managed surgically, with the addition of radiotherapy for locally advanced disease. Current photon-based radiotherapy results in a high treatment-related complications, due to proximal organ involvement. The anatomic location of the esophagus raises challenges due to the anatomical changes associated with diaphragmatic motion, weight loss, tumor changes, and set-up variability. These propelled the interest in proton beam therapy (PBT), which theoretically offers a reduction in the radiation exposure to healthy neighboring tissues with improvements in the therapeutic ratio. In this review, we present the role of PBT for esophageal cancer, including treatment planning, early clinical comparisons with photon-based techniques, ongoing trials, current challenges, toxicities, and issues of equity and health services.

Abstract

Early-stage esophageal cancer is often primarily managed surgically, with the addition of radiotherapy for locally advanced disease. However, current photon-based radiotherapy regimens and surgery results in a high incidence of treatment-related cardiac and pulmonary complications due to the involvement of proximal organs at risk. In addition, the anatomic location of the esophagus raises challenges for radiotherapy due to the anatomical changes associated with diaphragmatic motion, weight loss, tumor changes, and set-up variability. These challenges propelled the interest in proton beam therapy (PBT), which theoretically offers a reduction in the radiation exposure to healthy neighboring tissues with improvements in the therapeutic ratio. Several dosimetric studies support the potential advantages of PBT for esophageal cancer treatment however, translation of these results to improved clinical outcomes remains unclear with limited clinical data, especially in large populations. Studies on the effect on quality of life are likewise lacking. Here, we review the existing and emerging role of PBT for esophageal cancer, including treatment planning, early clinical comparisons of PBT with photon-based techniques, recently concluded and ongoing clinical trials, challenges and toxicities, effects on quality of life, and global inequities in the treatment of esophageal cancer.

Health Care Resource Utilization for Esophageal Cancer Using Proton versus Photon Radiation Therapy

Purpose

In patients treated with chemoradiation for esophageal cancer (EC), randomized trial data demonstrate that proton beam therapy (PBT) reduces toxicities and postoperative complications (POCs) compared with intensity-modulated radiation therapy (IMRT). However, whether radiation therapy modality affects postoperative health care resource utilization remains unknown.

Materials and Methods

We examined 287 patients with EC who received chemoradiation (prescribed 50.4 Gy/GyE) followed by esophagectomy, including a real-world observational cohort of 237 consecutive patients treated from 2007 to 2013 with PBT (n = 81) versus IMRT (n = 156); and an independent, contemporary comparison cohort of 50 patients from a randomized trial treated from 2012 to 2019 with PBT (n = 21) versus IMRT (n = 29). Postoperative complications were abstracted from medical records. Health care charges were obtained from institutional claims and adjusted for inflation (2021 dollars). Charge differences (Δ = $PBT - $IMRT) were compared by treatment using adjusted generalized linear models with the gamma distribution.

Results

Baseline PBT versus IMRT characteristics were not significantly different. In the observational cohort, during the neoadjuvant chemoradiation phase, health care charges were higher for PBT versus IMRT (Δ = +$71,959; 95% confidence interval [CI], $62,274-$82,138; P < .001). There was no difference in surgical charges (Δ = -$2234; 95% CI, -$6003 to $1695; P = .26). However, during postoperative hospitalization following esophagectomy, health care charges were lower for PBT versus IMRT (Δ = -$25,115; 95% CI, -$37,625 to -$9776; P = .003). In the comparison cohort, findings were analogous: Charges were higher for PBT versus IMRT during chemoradiation (Δ = +$61,818; 95% CI, $49,435-$75,069; P < .001), not different for surgery (Δ = -$4784; 95% CI, -$6439 to $3487; P = .25), and lower for PBT postoperatively (Δ = -$27,048; 95% CI, -$41,974 to -$5300; P = .02). Lower postoperative charges for PBT were especially seen among patients with any POCs in the contemporary comparison (Δ = -$176,448; 95% CI, -$209,782 to -$78,813; P = .02).

Conclusion

Higher up-front chemoradiation resource utilization for PBT in patients with EC was partially offset postoperatively, moderated by reduction in POC risks. Results extend existing clinical evidence of toxicity reduction with PBT.

A Systematic Review of Cost-Effectiveness Studies of Stereotactic Radiotherapy for Cancer Oligometastases

PURPOSE

It is crucial to economically justify the use of promising therapies such as stereotactic ablative radiotherapy (SABR) for oligometastatic disease (OMD). The goal of this systematic review was to summatively evaluate publications that analyzed the cost-effectiveness of SABR for OMD.

METHODS AND MATERIALS

Using PRISMA-guided methodology, PubMed and EMBASE were searched for modeling-based cost effectiveness (CE) studies for various forms of limited metastatic disease. Only full publications that specifically compared SABR with a systemic therapy-based approach were included.

RESULTS

Of 9 studies, 4 pertained to OMD with mixed histologies, 2 to oligometastatic non-small cell lung cancer, 1 to pulmonary OMD, 1 to liver OMD, and 1 to low-volume oligorecurrent castration-sensitive prostate cancer. All but one investigation illustrated that SABR was cost-effective for the studied population (or a subpopulation); of these studies, the incremental CE ratios (ICERs) for SABR (when reported) ranged from $28,000/quality-adjusted life-year (QALY) to $55,000/QALY. Of studies that reported the probability of SABR being cost-effective at common willingness-to-pay values, the median (range) probability of achieving CE was roughly 61% (30-88%) at a $50,000/QALY threshold and 78% (31%-100%) at a $100,000/QALY threshold.

CONCLUSIONS

The available evidence suggests that SABR is a cost-effective approach for OMD, which has implications for value-based oncologic practice and construction of future health policies. However, re-assessment is required in the context of modern systemic therapies (e.g. immunotherapy) as well as long-term follow-up of existing and newly reported randomized trials. Prudent patient selection remains the single most important factor influencing the CE of SABR for OMD.

Assessment of Proton Beam Therapy Use Among Patients With Newly Diagnosed Cancer in the US, 2004-2018

IMPORTANCE

Proton beam therapy (PBT) is a potentially superior technology to photon radiotherapy for tumors with complex anatomy, those surrounded by sensitive tissues, and childhood cancers.

OBJECTIVE

To assess patterns of use of PBT according to the present American Society of Radiation Oncology (ASTRO) clinical indications in the US.

DESIGN, SETTING, AND PARTICIPANTS

Individuals newly diagnosed with cancer between 2004 and 2018 were selected from the National Cancer Database. Data analysis was performed from October 4, 2021, to February 22, 2022. ASTRO's Model Policies (2017) were used to classify patients into group 1, for which health insurance coverage for PBT treatment is recommended, and group 2, for which coverage is recommended only if additional requirements are met.

MAIN OUTCOMES AND MEASURES

Use of PBT.

RESULTS

Of the 5 919 368 patients eligible to receive PBT included in the study, 3 206 902 were female (54.2%), and mean (SD) age at diagnosis was 62.6 (12.3) years. Use of PBT in the US increased from 0.4% in 2004 to 1.2% in 2018 (annual percent change [APC], 8.12%; P < .001) due to increases in group 1 from 0.4% in 2010 to 2.2% in 2018 (APC, 21.97; P < .001) and increases in group 2 from 0.03% in 2014 to 0.1% in 2018 (APC, 30.57; P < .001). From 2010 to 2018, among patients in group 2, PBT targeted to the breast increased from 0.0% to 0.9% (APC, 51.95%), and PBT targeted to the lung increased from 0.1% to 0.7% (APC, 28.06%) (P < .001 for both). Use of PBT targeted to the prostate decreased from 1.4% in 2011 to 0.8% in 2014 (APC, -16.48%; P = .03) then increased to 1.3% in 2018 (APC, 12.45; P < .001). Most patients in group 1 treated with PBT had private insurance coverage in 2018 (1039 [55.4%]); Medicare was the most common insurance type among those in group 2 (1973 [52.5%]).

CONCLUSIONS AND RELEVANCE

The findings of this study show an increase in the use of PBT in the US between 2004 to 2018; prostate was the only cancer site for which PBT use decreased temporarily between 2011 and 2014, increasing again between 2014 and 2018. These findings may be especially relevant for Medicare radiation oncology coverage policies.

An comparison of acute toxicities and patient-reported outcomes between intensity-modulated proton therapy and volumetric-modulated arc therapy after ipsilateral radiation for head and neck cancers

BACKGROUND

Intensity-modulated proton therapy (IMPT) demonstrates superior dose distribution over volumetric-modulated arc therapy (VMAT) for sparing organs-at-risk (OARs) in ipsilateral radiotherapy. To determine a clinical benefit, assessment of patient-reported outcomes (PRO) and physician-reported toxicities alongside a dosimetric analysis is needed.

METHODS

Plans were analyzed for dosimetric differences. PROs were compared for patients undergoing ipsilateral curative-intent radiotherapy for tonsil and salivary gland cancers with VMAT or IMPT from 2015 to 2020. Physician-reported toxicities were compared.

RESULTS

In 40 patients, IMPT was associated with decreased dose to multiple OARs and less deterioration in the following PROs: pain, swallowing function, dry mouth, sticky saliva, sensory change, cough, speech, feeling ill, and social eating. Physician-reported toxicities demonstrated less oral pain.

CONCLUSION

IMPT is associated with decreased dose to OARs and less patient-reported acute deterioration in multiple head and neck domains. A strong consideration for IMPT in ipsilateral head and neck patients with cancer is warranted.

Assessment of MRI-Linac Economics under the RO-APM

The implementation of the radiation oncology alternative payment model (RO-APM) has raised concerns regarding the development of MRI-guided adaptive radiotherapy (MRgART). We sought to compare technical fee reimbursement under Fee-For-Service (FFS) to the proposed RO-APM for a typical MRI-Linac (MRL) patient load and distribution of 200 patients. In an exploratory aim, a modifier was added to the RO-APM (mRO-APM) to account for the resources necessary to provide this care. Traditional Medicare FFS reimbursement rates were compared to the diagnosis-based reimbursement in the RO-APM. Reimbursement for all selected diagnoses were lower in the RO-APM compared to FFS, with the largest differences in the adaptive treatments for lung cancer (−89%) and pancreatic cancer (−83%). The total annual reimbursement discrepancy amounted to −78%. Without implementation of adaptive replanning there was no difference in reimbursement in breast, colorectal and prostate cancer between RO-APM and mRO-APM. Accommodating online adaptive treatments in the mRO-APM would result in a reimbursement difference from the FFS model of −47% for lung cancer and −46% for pancreatic cancer, mitigating the overall annual reimbursement difference to −54%. Even with adjustment, the implementation of MRgART as a new treatment strategy is susceptible under the RO-APM.

A Novel Model and Infrastructure for Clinical Outcomes Data Collection and Their Systematic Evaluation for UK Patients Receiving Proton Beam Therapy

AIMS

To establish an infrastructure for sustainable, comprehensive data collection and systematic outcomes evaluation for UK patients receiving proton beam therapy (PBT).

MATERIALS AND METHODS

A Proton Outcomes Working Group was formed in 2014 to develop a national minimum dataset for PBT patients and to define a clinically integrated informatics solution for data collection. The Christie Proton Beam Therapy Centre formed its Proton Clinical Outcomes Unit in 2018 to collect, curate and analyse outcomes data prospectively for UK-treated patients and retrospectively for UK patients referred abroad for PBT since 2008 via the Proton Overseas Programme (POP).

RESULTS

A single electronic form (eForm) was developed to capture the agreed data, using a data tree approach including conditional logic: data items are requested once, further questions depend on previous answers and are sensitive to tumour site and patient pathway time point. Relevant data automatically populate other forms, saving time, prompting completeness of clinical assessments and ensuring data consistency. Completed eForm data populate the electronic patient record and generate individualised outputs, including consultation letters, treatment summary and surveillance plans, based on organs at risk irradiated, age and sex. All data regarding POP-treated patients are verified and migrated into the system, ensuring that patient data, whether overseas or UK treated, are consistently recorded. The eForm utilises a 'user friendly' web portal interface, the Clinical Web Portal, including clickable tables and infographics. Data items are coded to a universally recognised standard comparable with other data systems. Patient-reported outcomes are also integrated, highlighting significant toxicities and prompting a response. Outcomes data can be correlated with dosimetric DICOM data to support radiation dose modelling.

CONCLUSION

Outcomes data from both POP-treated and The Christie-treated patients support long-term care, allow evaluation of PBT efficacy and safety, assist future selection of PBT patients and support hypothesis generation for future clinical trials.

Assessing concordance between patient-reported and investigator-reported CTCAE after proton beam therapy for prostate cancer

PURPOSE

We report acute patient-reported outcomes using CTCAE (PRO-CTCAE) of proton beam radiotherapy for high-risk or unfavorable intermediate-risk prostate cancer in a prospective clinical trial. PRO-CTCAE were correlated with investigator reported-CTCAE (IR-CTCAE) to assess the degree of concordance.

METHODS AND MATERIALS

11 PRO-CTCAE questions assessed gastrointestinal (GI), genitourinary (GU), or erectile function side effects. The correlation scheme between PRO-CTCAE and IR-CTCAE was independently developed by two physicians. Analyses of PRO-CTCAE and IR-CTCAE were conducted using both descriptive terms and the converted grade scores. The Kappa statistic described the degree of concordance.

RESULTS

55 patients were included. IR-CTCAE underestimated diarrhea compared to PRO-CTCAE at the end of treatment (EOT), with a 28% rate of underestimation (11% by ≥ 2 toxicity grades). Similarly, urinary tract pain was underestimated in 45% of cases (17% by ≥ 2 grades) at EOT. Differences were less pronounced at baseline or 3 months after radiotherapy. The incidence of urinary urgency and frequency tended to be overestimated prior to treatment (36% and 24%, respectively) but underestimated at EOT (35% and 31%, respectively). The degree of interference with daily activities was consistently overestimated by investigators (45%-85%). Finally, erectile dysfunction showed a 36-56% rate of discordance by ≥ 2 toxicity grades.

CONCLUSIONS

Our study shows a low agreement between IR-CTCAE and PRO-CTCAE in the setting of proton therapy for prostate cancer. Compared to patient-reported outcomes, physicians underestimated the frequency and severity of urinary symptoms and diarrhea at the end of treatment. Continued use of PROs should be strongly encouraged.

Models for Translational Proton Radiobiology-From Bench to Bedside and Back

The number of proton therapy centers worldwide are increasing steadily, with more than two million cancer patients treated so far. Despite this development, pending questions on proton radiobiology still call for basic and translational preclinical research. Open issues are the on-going discussion on an energy-dependent varying proton RBE (relative biological effectiveness), a better characterization of normal tissue side effects and combination treatments with drugs originally developed for photon therapy. At the same time, novel possibilities arise, such as radioimmunotherapy, and new proton therapy schemata, such as FLASH irradiation and proton mini-beams. The study of those aspects demands for radiobiological models at different stages along the translational chain, allowing the investigation of mechanisms from the molecular level to whole organisms. Focusing on the challenges and specifics of proton research, this review summarizes the different available models, ranging from in vitro systems to animal studies of increasing complexity as well as complementing in silico approaches.

Young Adult Populations Face Yet Another Barrier to Care With Insurers: Limited Access to Proton Therapy

PURPOSE

Young patients, including pediatric, adolescent, and young adult (YA) patients, are most likely to benefit from the reduced integral dose of proton beam radiation therapy (PBT) resulting in fewer late toxicities and secondary malignancies. This study sought to examine insurance approval and appeal outcomes for PBT among YA patients compared with pediatric patients at a large-volume proton therapy center.

METHODS AND MATERIALS

We performed a cross-sectional cohort study of 284 consecutive patients aged 0 to 39 years for whom PBT was recommended in 2018 through 2019. Pediatric patients were defined as aged 0 to 18 years and YA patients 19 to 39 years. Rates of approval, denials, and decision timelines were calculated. Tumor type and location were also evaluated as factors that may influence insurance decisions.

RESULTS

A total of 207 patients (73%) were approved for PBT at initial request. YA patients (n = 68/143, 48%) were significantly less likely to receive initial approval compared with pediatric patients (n = 139/141; 99%) (P < .001). Even after 47% (n = 35 of 75) of the PBT denials for YA patients were overturned, YAs had a significantly lower final PBT approval (72% vs pediatric 99%; P < .001). The median wait time was also significantly longer for YA patients (median, 8 days; interquartile range [IQR] 3-17 vs median, 2 days; IQR, 0-6; P < .001). In those patients requiring an appeal, the median wait time was 16 days (IQR, 9-25).

CONCLUSION

Given the decades of survivorship of YA patients, PBT is an important tool to reduce late toxicities and secondary malignancies. Compared with pediatric patients, YA patients are significantly less likely to receive insurance approval for PBT. Insurance denials and subsequent appeal requests result in significant delays for YA patients. Insurers need to re-examine their policies to include expedited decisions and appeals and removal of arbitrary age cutoffs so that YA patients can gain easier access to PBT. Furthermore, consensus guidelines encouraging greater PBT access for YA may be warranted from both medical societies and/or AYA experts.

Geospatial Disparities in Access to Proton Therapy in the Continental United States

Proton therapy (PT) is an important component of therapy for select cancers, but no formal study of geospatial access to PT has been conducted to date. Population data for 320.7 million people in 32,644 zip codes were analyzed. Median travel time was 1.61 (IQR 0.67-3.36) hours for children and 1.64 (IQR 0.69-3.33) hours for adults. Significant variation in travel time to nearest PT center was observed between states. The West has a longer median travel time of 3.51 (IQR 1.15-7.13) hours when compared to the Midwest (1.70, IQR 0.79-2.69), South (1.60, IQR 0.61-3.12) and Northeast (1.04, IQR 0.57-2.01).

Considerations for Clinical Trials Testing Radiotherapy Combined With Immunotherapy for Metastatic Disease

Metastatic cancer is inherently heterogeneous, and patients with metastatic disease can experience vastly different oncologic outcomes depending on several patient- and disease-specific characteristics. Designing trials for such a diverse population is challenging yet necessary to improve treatment outcomes for metastatic-previously thought to be incurable-disease. Here we review core considerations for designing and conducting clinical trials involving radiation therapy and immunotherapy for patients with metastatic cancer.

Clinical Review of Proton Therapy in the Treatment of Unilateral Head and Neck Cancers

Radiotherapy is a common treatment modality in the management of head and neck malignancies. In select clinical scenarios of well-lateralized tumors, radiotherapy can be delivered to the primary tumor or tumor bed and the ipsilateral nodal regions, while intentional irradiation of the contralateral neck is omitted. Proton beam therapy is an advanced radiotherapy modality that allows for the elimination of exit-dose through nontarget tissues such as the oral cavity. This dosimetric advantage is apt for unilateral treatments. By eliminating excess dose to midline and contralateral organs at risk and conforming dose around complex anatomy, proton beam therapy can reduce the risk of iatrogenic toxicities. Currently, there is no level I evidence comparing proton beam therapy to conventional photon radiation modalities for unilateral head and neck cancers. However, a growing body of retrospective and prospective evidence is now available describing the dosimetric and clinical advantages of proton beam therapy. Subsequently, the intent of this clinical review is to summarize the current evidence supporting the use of proton beam therapy in unilateral irradiation of head and neck cancers, including evaluation of disease site-specific evidence, unique challenging clinical scenarios, and ongoing clinical trials.

Identification of patient benefit from proton beam therapy in brain tumour patients based on dosimetric and NTCP analyses

BACKGROUND

The limited availability of proton beam therapy (PBT) requires individual treatment selection strategies, such as the model-based approach. In this study, we assessed the dosimetric benefit of PBT compared to photon therapy (XRT), analysed the corresponding changes in normal tissue complication probability (NTCP) on a variety of available models, and illustrated model-based patient selection in an in-silico study for patients with brain tumours.

METHODS

For 92 patients treated at two PBT centres, volumetric modulated arc therapy treatment plans were retrospectively created for comparison with the clinically applied PBT plans. Several dosimetric parameters for the brain excluding tumour and margins, cerebellum, brain stem, frontal and temporal lobes, hippocampi, cochleae, chiasm, optic nerves, lacrimal glands, lenses, pituitary gland, and skin were compared between both modalities using Wilcoxon signed-rank tests. NTCP differences (ΔNTCP) were calculated for 11 models predicting brain necrosis, delayed recall, temporal lobe injury, hearing loss, tinnitus, blindness, ocular toxicity, cataract, endocrine dysfunction, alopecia, and erythema. A patient was assumed to be selected for PBT if ΔNTCP exceeded a threshold of 10 percentage points for at least one of the side-effects.

RESULTS

PBT substantially reduced the dose in almost all investigated OARs, especially in the low and intermediate dose ranges and for contralateral organs. In general, NTCP predictions were significantly lower for PBT compared to XRT, in particular in ipsilateral organs. Considering ΔNTCP of all models, 80 patients (87.0%) would have been selected for PBT in this in-silico study, mainly due to predictions of a model on delayed recall (51 patients).

CONCLUSION

In this study, substantial dose reductions for PBT were observed, mainly in contralateral organs. However, due to the sigmoidal dose response, NTCP was particularly reduced in ipsilateral organs. This underlines that physical dose-volume parameters alone may not be sufficient to describe the clinical relevance between different treatment techniques and highlights potential benefits of NTCP models. Further NTCP models for different modern treatment techniques are mandatory and existing models have to be externally validated in order to implement the model-based approach in clinical practice for cranial radiotherapy.

Proton Therapy for Partial Breast Irradiation: Rationale and Considerations

In an era of continued advancements in personalized medicine for the treatment of breast cancer, select patients with early stage breast cancer may be uniquely poised to benefit from partial breast irradiation (PBI) delivered with proton therapy. PBI presents an opportunity to improve quality of life during treatment with a significantly shorter treatment duration. By targeting less non-target breast tissue, excess radiation exposure and resulting toxicities are also reduced. Proton therapy represents a precision radiotherapy technology that builds on these advantages by further limiting the normal tissue exposure to unnecessary radiation dose not only to uninvolved breast tissue but also the underlying thoracic organs including the heart and lungs. Herein, we present a concise review of the rationale for the use of proton therapy for PBI, evidence available to date, and practical considerations in the implementation and use of proton therapy for this indication.

The Role of Plan Robustness Evaluation in Comparing Protons and Photons Plans - An Application on IMPT and IMRT Plans in Skull Base Chordomas

Purpose:

To analyze robustness of treatment plans optimized using different approaches in intensity modulated proton therapy (IMPT) and investigate the necessity of robust optimization and evaluation in intensity modulated radiotherapy (IMRT) plans for skull base chordomas.

Materials and Methods:

Two photon plans, standard IMRT and robustly optimized IMRT (RB-IMRT), and two IMPT plans, robustly optimized multi field optimization (MFO) and hybrid-MFO (HB-MFO), were created in RayStation TPS for five patients previously treated using single field uniform optimization (SFO). Both set-up and range uncertainties were incorporated during robust optimization of IMPT plans whereas only set-up uncertainty was used in RB-IMRT. The dosimetric outcomes from the five planning techniques were compared for every patient using standard dose volume indices and integral dose (ID) estimated for target and organs at risk (OARs). Robustness of each treatment plan was assessed by introducing set-up uncertainties of ±3 mm along the three translational axes and, only in protons, an additional range uncertainty of ±3.5%.

Results:

All the five nominal plans provided comparable and clinically acceptable target coverage. In comparison to nominal plans, worst case decrease in D_95% of clinical target volume-high risk (CTV-HR) were 11.1%, 13.5%, and 13.6% for SFO, MFO, and HB-MFO plans respectively. The corresponding values were 13.7% for standard IMRT which improved to 11.5% for RB-IMRT. The worst case increased in high dose (D_1%) to CTV-HR was highest in IMRT (2.1%) and lowest in SFO (0.7%) plans. Moreover, IMRT showed worst case increases in D_1% for all neurological OARs and were lowest for SFO plans. The worst case D_1% for brainstem, chiasm, spinal cord, optic nerves, and temporal lobes were increased by 29%, 41%, 30%, 41% and 14% for IMRT and 18%, 21%, 21%, 24%, and 7% for SFO plans, respectively. In comparison to IMRT, RB-IMRT improved D_1% of all neurological OARs ranging from 5% to 14% in worst case scenarios.

Conclusion:

Based on the five cases presented in the current study, all proton planning techniques (SFO, MFO and HB-MFO) were robust both for target coverage and OARs sparing. Standard IMRT plans were less robust than proton plans in regards to high doses to neurological OARs. However, robust optimization applied to IMRT resulted in improved robustness in both target coverage and high doses to OARs. Robustness evaluation may be considered as a part of plan evaluation procedure even in IMRT.

Using patient-specific bolus for pencil beam scanning proton treatment of periorbital disease

Purpose

A unique mantle cell lymphoma case with bilateral periorbital disease unresponsive to chemotherapy and with dosimetry not conducive to electron therapy was treated with pencil beam scanning (PBS) proton therapy. This patient presented treatment planning challenges due to the thin target, immediately adjacent organs at risk (OAR), and nonconformal orbital surface anatomy. Therefore, we developed a patient‐specific bolus and hypothesized that it would provide superior setup robustness, dose uniformity and dose conformity.

Materials/Methods

A blue‐wax patient‐specific bolus was generated from the patient's face contour to conform to his face and eliminate air gaps. A relative stopping power ratio (RSP) of 0.972 was measured for the blue‐wax, and the HUs were overridden accordingly in the treatment planning system (TPS). Orthogonal kV images were used for bony alignment and then to ensure positioning of the bolus through fiducial markers attached to the bolus and their contours in TPS. Daily CBCT was used to confirm the position of the bolus in relation to the patient's surface. Dosimetric characteristics were compared between (a) nonbolus, (b) conventional gel bolus and (c) patient‐specific bolus plans. An in‐house developed workflow for assessment of daily treatment dose based on CBCT images was used to evaluate inter‐fraction dose accumulation.

Results

The patient was treated to 24 cobalt gray equivalent (CGE) in 2 CGE daily fractions to the bilateral periorbital skin, constraining at least 50% of each lacrimal gland to under 20 Gy. The bolus increased proton beam range by adding 2–3 energy layers of different fields to help achieve better dose uniformity and adequate dose coverage. In contrast to the plan with conventional gel bolus, dose uniformity was significantly improved with patient‐specific bolus. The global maximum dose was reduced by 7% (from 116% to 109%). The max and mean doses were reduced by 6.0% and 7.7%, respectively, for bilateral retinas, and 3.0% and 13.9% for bilateral lacrimal glands. The max dose of the lens was reduced by 2.1%. The rigid shape, along with lightweight, and smooth fit to the patient face was well tolerated and reported as “very comfortable” by the patient. The daily position accuracy of the bolus was within 1 mm based on IGRT marker alignment. The daily dose accumulation indicates that the target coverage and OAR doses were highly consistent with the planning intention.

Conclusion

Our patient‐specific blue‐wax bolus significantly increased dose uniformity, reduced OAR doses, and maintained consistent setup accuracy compared to conventional bolus. Quality PBS proton treatment for periorbital tumors and similar challenging thin and shallow targets can be achieved using such patient‐specific bolus with robustness on both setup and dosimetry.

The Art of Living With Symptoms: A Qualitative Study Among Patients With Primary Brain Tumors Receiving Proton Beam Therapy

Symptom management in conjunction with proton beam therapy (PBT) from patient's perspective has not been explored. Such knowledge is essential to optimize the care in this relatively new treatment modality.

Comparative Analysis of 5-Year Clinical Outcomes and Patterns of Failure of Proton Beam Therapy Versus Intensity Modulated Radiation therapy for Prostate Cancer in the Postoperative Setting

PURPOSE

Although proton beam therapy (PBT) is a rapidly expanding modality to treat prostate cancer compared with intensity modulated radiation therapy (IMRT), data comparing disease control outcomes and patterns of failure in the postprostatectomy setting remain substantially limited.

METHODS AND MATERIALS

All patients who underwent postoperative IMRT or PBT to the prostate bed only at a single institution were included (2009-2017). Endpoints included biochemical failure (BF; using institutional and recent cooperative group trial definitions), local failure (LF), regional failure (RF), distant failure (DF), and all-cause mortality. A case-matched cohort analysis was performed using 3-to-1 nearest-neighbor matching; multivariable Cox proportional hazards modeling (MVA) estimated hazard ratios for disease-related outcomes by treatment modality.

RESULTS

Of 295 men, 260 were matched (n = 65 PBT, 195 IMRT); after matching, only age at diagnosis (P < .01) significantly differed between cohorts. At a median follow-up of 59 months, BF (institution-defined), LF, RF, DF, and mortality rates were 45% (n = 29), 2% (n = 1), 9% (n = 6), 9% (n = 6), and 2% (n = 1) for PBT, and 41% (n = 80), 3% (n = 5), 7% (n = 13), 9% (n = 18), and 5% (n = 9) for IMRT (all P > .05). RT modality was not significantly associated with BF on MVA using institutional or cooperative group definitions (all P > .05), nor with LF (P = .82), RF (P = .11), DF (P = .36), or all-cause mortality (P = .69). Patterns of failure were qualitatively similar between cohorts (DF: bone, retroperitoneal nodes, lung).

CONCLUSIONS

In this single institution, case-matched analysis, PBT yielded similar long-term disease-related outcomes and patterns of failure to IMRT in the postprostatectomy setting.

[Proton therapy-a chance in the treatment of tumors of the head and neck and base of skull]

BACKGROUND

Radiotherapy (RT) is an integral part of the treatment of many tumors located in the vicinity of sensitive organs and structures, including tumors of the head and neck and base of skull in particular. Due to the risk of side effects associated with RT, the use of highly conformal RT techniques is favored. For many indications, proton therapy (PT) is therefore already part of the modern treatment standard.

OBJECTIVE

This article presents an overview of current indications for PT with emphasis on tumors in the head and neck region and the base of skull. Furthermore, a summary and discussion of relevant results and current developments are included.

MATERIALS AND METHODS

The work comprises an evaluation of relevant studies and an overview of current issues related to PT of tumors in the areas of the head, neck, and base of skull.

RESULTS

Overall, the studies on PT show promising results. In addition to dosimetric studies, clinical studies also point to advantages of PT, especially with regard to the reduction of side effects.

DISCUSSION

Currently, use of the model-based approach is being discussed. This is intended to identify those patients who benefit most from PT based on the normal tissue complication probability (NTCP). PT for re-RT is also discussed.

Characterization of health-related quality of life based on the EQ-5D-5L questionnaire in head-and-neck cancer patients undergoing modern radiotherapy

Background: Patient-reported quality of life in cancer patients is becoming increasingly important, especially for head-and-neck (H&N) cancers, which are at risk of experiencing severe treatment-related toxicities. Therefore, we sought to characterize the peritherapeutic HRQOL of contemporary patients using the well-validated EQ-5D-5 L questionnaire. Methods: All patients receiving radiotherapy for H&N cancers between July 2019 and November 2019 at the University of Freiburg Medical Center who completed the first two follow-ups were included. Results: All 49 patients completed the questionnaires at all time points of data collection, yielding 196 total questionnaires. The mean EQ-5D-5 L index score of the overall population before radiotherapy, after radiotherapy, and three and six months following radiotherapy was 0.837 (standard deviation, SD 0.17), 0.828 (SD 0.16), 0.855 (SD 0.15), and 0.856 (SD 0.14) respectively. The respective mean EQ VAS scores were 63.88 (SD 20.72), 63.67 (SD 21.81), 63.67 (SD 21.81), and 65.20 (SD 22.41) respectively. The respective changes of the HI and EQ VAS score over time for this cohort were not significant (Friedman test p = 0.273, p = 0.618). Conclusion: Despite the known therapy-related toxicities, no significant permanent deterioration of HRQOL in this cohort was observed.

Patients' perspective in the context of proton beam therapy: summary of a Nordic workshop

INTRODUCTION

On 15-16 November 2019, the Skandion Clinic in Sweden hosted the first Nordic workshop on 'Patients' perspective in proton beam therapy'. The workshop was conducted to describe and compare the patient care in PBT clinics in the Nordic countries and to initiate a collaboration, with the target to ensure patient participation and reduce the risk of inequity of access by lowering the barriers for accepting PBT in a distant clinic. The overarching aim of this workshop was to describe and compare the use of patients' perspectives in the Nordic PBT clinics.

MATERIAL AND METHODS

Twelve participants attended the workshop, representing Denmark, Norway and Sweden. The participants were registered nurses working in patient care, researchers, physicist and leaders of the Skandion Clinic.

RESULTS

The consensus of the workshop was that systematic use of patient experiences on individual and group level is essential for developing clinical practice and understanding the overall effects of PBT. A difference in how the Nordic countries use patient experiences in clinical practise was found. The importance of lowering the barriers for participation in national proton trials and proton treatment were emphasized, however, there is a lack of knowledge about individual and organizational barriers to accepting PBT, and further research is therefore needed.

CONCLUSION

Collaboration between the Nordic countries regarding patients' perspectives in the context of PBT is of importance to compare national differences as well as to find similarities, but most importantly to learn from each other and to improve patient care. Nordic collaboration with focus on systematic collection of patient-reported outcomes in the context of PBT is unique. Collaboration in research offers the possibility to increase the inclusion of patients' perspectives in study protocols.

[Proton therapy-a chance in the treatment of tumors of the head and neck and base of skull]

BACKGROUND

Radiotherapy (RT) is an integral part of the treatment of many tumors located in the vicinity of sensitive organs and structures, including tumors of the head and neck and base of skull in particular. Due to the risk of side effects associated with RT, the use of highly conformal RT techniques is favored. For many indications, proton therapy (PT) is therefore already part of the modern treatment standard.

OBJECTIVE

This article presents an overview of current indications for PT with emphasis on tumors in the head and neck region and the base of skull. Furthermore, a summary and discussion of relevant results and current developments are included.

MATERIALS AND METHODS

The work comprises an evaluation of relevant studies and an overview of current issues related to PT of tumors in the areas of the head, neck, and base of skull.

RESULTS

Overall, the studies on PT show promising results. In addition to dosimetric studies, clinical studies also point to advantages of PT, especially with regard to the reduction of side effects.

DISCUSSION

Currently, use of the model-based approach is being discussed. This is intended to identify those patients who benefit most from PT based on the normal tissue complication probability (NTCP). PT for re-RT is also discussed.

The MOMENTUM Study: An International Registry for the Evidence-Based Introduction of MR-Guided Adaptive Therapy

Purpose: MR-guided Radiation Therapy (MRgRT) allows for high-precision radiotherapy under real-time MR visualization. This enables margin reduction and subsequent dose escalation which may lead to higher tumor control and less toxicity. The Unity MR-linac (Elekta AB, Stockholm, Sweden) integrates a linear accelerator with a 1.5T diagnostic quality MRI and an online adaptive workflow. A prospective international registry was established to facilitate the evidence-based implementation of the Unity MR-linac into clinical practice, to systemically evaluate long-term outcomes, and to aid further technical development of MR-linac-based MRgRT. Methods and Results: In February 2019, the Multi-OutcoMe EvaluatioN of radiation Therapy Using the MR-linac study (MOMENTUM) started within the MR-linac Consortium. The MOMENTUM study is an international academic-industrial partnership between several hospitals and industry partner Elekta. All patients treated on the MR-linac are eligible for inclusion in MOMENTUM. For participants, we collect clinical patient data (e.g., patient, tumor, and treatment characteristics) and technical patient data which is defined as information generated on the MR-linac during treatment. The data are captured, pseudonymized, and stored in an international registry at set time intervals up to two years after treatment. Patients can choose to provide patient-reported outcomes and consent to additional MRI scans acquired on the MR-linac. This registry will serve as a data platform that supports multicenter research investigating the MR-linac. Rules and regulations on data sharing, data access, and intellectual property rights are summarized in an academic-industrial collaboration agreement. Data access rules ensure secure data handling and research integrity for investigators and institutions. Separate data access rules exist for academic and industry partners. This study is registered at ClinicalTrials.gov with ID: NCT04075305 (https://clinicaltrials.gov/ct2/show/NCT04075305). Conclusion: The multi-institutional MOMENTUM study has been set up to collect clinical and technical patient data to advance technical development, and facilitate evidenced-based implementation of MR-linac technology with the ultimate purpose to improve tumor control, survival, and quality of life of patients with cancer.

Proton Reirradiation: Expert Recommendations for Reducing Toxicities and Offering New Chances of Cure in Patients With Challenging Recurrence Malignancies

Local and regional recurrences are common following an initial course of radiotherapy, yet management of these recurrences remains a challenge. Reirradiation may be an optimal treatment approach for providing durable tumor control and even offering select patients with locoregional recurrences or new primary tumors a chance of cure, but photon reirradiation can be associated with considerable risks of high grade acute and late toxicities. The high conformality and lack of exit dose with proton therapy offer significant advantages for reirradiation. By decreasing dose to adjacent normal tissues, proton therapy can more safely deliver definitive instead of palliative doses of reirradiation, more safely dose escalate reirradiation treatment, and more safely allow for concurrent systemic therapy in the reirradiation setting. In this case-based analysis, renowned experts in the fields of proton therapy and of reirradiation present cases for which they recently employed proton reirradiation. This manuscript focuses on case studies in patients with lung cancer, head and neck malignancies, and pelvic malignancies. Considerations for when to deliver proton therapy in the reirradiation setting and the pros and cons of proton therapy are discussed, and the existing literature supporting the use of proton reirradiation for these disease sites is assessed.

Prioritization of Proton Patients in the COVID-19 Pandemic: Recommendations from The New York Proton Center

It has been well documented from the early days of the 2019 novel coronavirus (COVID-19) pandemic that patients with a diagnosis of cancer are not only at higher risks of contracting a COVID-19 infection but also at higher risks of suffering severe, and possibly fatal, outcomes from the infection. Given that the United States has the greatest number of positive coronavirus cases, it is likely that many, if not all, radiation oncology clinics will be faced with the challenge of safely balancing a patient's risk of contracting COVID-19, while under active radiation treatment, against their risk of cancer progression if treatment is delayed. To address this challenge, the New York Proton Center established an internal algorithm that considers treatment-related, tumor-related, and patient-related characteristics. Despite having suffered staff shortages due to illness, this algorithm has allowed the center to maintain patient treatment volumes while keeping the rate of COVID-19 infection low.

Dual-Color Plasmonic Nanosensor for Radiation Dosimetry

Radiation dosimeters are critical for accurately assessing the levels of radiation exposure of tumor sites and surrounding tissues and for optimizing therapeutic interventions as well as for monitoring environmental exposure. To fill the need for a simple, user-friendly, and inexpensive dosimeter, we designed an innovative colorimetric nanosensor-based assay for detecting ionizing radiation. We show that hydroxyl radicals generated by ionizing radiation can be used to etch gold nanorods (AuNRs) and silver nanoprisms (AgNPRs), yielding reproducible color changes for radiation dose detection in the range of 50-2000 rad, broad enough to cover doses used in hyperfractionated, conventional, and hypofractionated radiotherapy. This range of doses detected by this assay correlates with radiation-induced DNA damage response in mammalian cells. Furthermore, this AuNR- and AgNPR-based sensing platform has been established in a paper format that can be readily adopted for a wide range of applications and translation.

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.

Racial and Insurance-related Disparities in Delivery of Immunotherapy-type Compounds in the United States

Racial and/or socioeconomic factors affect the type of therapies delivered for non-small cell lung cancer (NSCLC). Given the rapid expansion of immunotherapy for NSCLC, it is a crucial public health priority to evaluate disparities in administration thereof. The National Cancer Database (NCDB) was queried for newly diagnosed metastatic NSCLC. Patients were dichotomized based on receipt of immunotherapy-type compounds (ICs) based on NCDB coding. Multivariable logistic regression ascertained factors associated with IC delivery. Subgroup analysis, performed by univariate logistic regression modeling, evaluated the effect of race while stratifying for insurance type. Of 504,447 patients, 11,420 (2.3%) received ICs, and 493,027 (97.7%) did not. From 2004 to 2012, ≤1% of patients received ICs; however, 4.9% did so in 2013, 6.6% in 2014, and 8.7% in 2015. ICs were more likely administered to younger and healthier patients, those living farther from treating facilities, and in more educated areas (P<0.05 for all). ICs were more often delivered to adenocarcinomas, and patients who received chemotherapy but not radiotherapy (P<0.05 for all). In addition to geographic differences, uninsured and Medicaid populations received ICs less often, along with African Americans. On subgroup analysis, African Americans were less likely to receive ICs even when stratified for Medicare, Medicaid, or private insurances. Because IC utilization is expected to amplify even further going forward, these public health and economic issues are essential to identify and address appropriately, and have implications on pharmaceutical/insurance companies, value-based oncology, and public health policy. Methods to address these inequalities are also discussed.

Randomized Phase IIB Trial of Proton Beam Therapy Versus Intensity-Modulated Radiation Therapy for Locally Advanced Esophageal Cancer

PURPOSE

Whether dosimetric advantages of proton beam therapy (PBT) translate to improved clinical outcomes compared with intensity-modulated radiation therapy (IMRT) remains unclear. This randomized trial compared total toxicity burden (TTB) and progression-free survival (PFS) between these modalities for esophageal cancer.

METHODS

This phase IIB trial randomly assigned patients to PBT or IMRT (50.4 Gy), stratified for histology, resectability, induction chemotherapy, and stage. The prespecified coprimary end points were TTB and PFS. TTB, a composite score of 11 distinct adverse events (AEs), including common toxicities as well as postoperative complications (POCs) in operated patients, quantified the extent of AE severity experienced over the duration of 1 year following treatment. The trial was conducted using Bayesian group sequential design with three planned interim analyses at 33%, 50%, and 67% of expected accrual (adjusted for follow-up).

RESULTS

This trial (commenced April 2012) was approved for closure and analysis upon activation of NRG-GI006 in March 2019, which occurred immediately prior to the planned 67% interim analysis. Altogether, 145 patients were randomly assigned (72 IMRT, 73 PBT), and 107 patients (61 IMRT, 46 PBT) were evaluable. Median follow-up was 44.1 months. Fifty-one patients (30 IMRT, 21 PBT) underwent esophagectomy; 80% of PBT was passive scattering. The posterior mean TTB was 2.3 times higher for IMRT (39.9; 95% highest posterior density interval, 26.2-54.9) than PBT (17.4; 10.5-25.0). The mean POC score was 7.6 times higher for IMRT (19.1; 7.3-32.3) versus PBT (2.5; 0.3-5.2). The posterior probability that mean TTB was lower for PBT compared with IMRT was 0.9989, which exceeded the trial's stopping boundary of 0.9942 at the 67% interim analysis. The 3-year PFS rate (50.8% v 51.2%) and 3-year overall survival rates (44.5% v 44.5%) were similar.

CONCLUSION

For locally advanced esophageal cancer, PBT reduced the risk and severity of AEs compared with IMRT while maintaining similar PFS.

Is there any benefit to particles over photon radiotherapy?

Particle, essentially, proton radiotherapy (RT) could provide some benefits over photon RT, especially in reducing the side effects of RT. We performed a systematic review to identify the performed randomised clinical trials (RCTs) and ongoing RCTs comparing particle RT with photon therapy. So far, there are no results available from phase 3 RCTs comparing particle RT with photon therapy. Furthermore, the results on side effects comparing proton and carbon ion beam RT with photon RT do vary. The introduction of new techniques in photon RT, such as image-guided RT (IGRT), intensity-modulated RT (IMRT), volumetric arc therapy (VMAT) and stereotactic body RT (SBRT) was already effective in reducing side effects. At present, the lack of evidence limits the indications for proton and carbon ion beam RTs and makes the particle RT still experimental.

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.

Systematic review of methodology used in clinical studies evaluating the benefits of proton beam therapy

BACKGROUND

Proton beam therapy (PBT) delivers high-energy radiation to target tumours while sparing surrounding normal tissues. The dosimetric advantages of PBT over traditional photon radiotherapy may be clear but the translation of this benefit into clinically meaningful reductions in toxicities and improved quality-of-life (QoL) needs to be determined. Randomised controlled trials (RCTs) are considered the gold standard for generating the highest-level evidence in medicine. The objectives of this systematic review were to provide an overview of published clinical studies evaluating the benefits of PBT, and to examine the methodology used in clinical trials with respect to study design and outcomes.

METHODS

PubMed, EMBASE and Cochrane databases were systematically searched for published clinical studies where PBT was a cancer treatment intervention. All randomised and non-randomised studies, prospective or retrospective, were eligible for inclusion.

RESULTS

In total, 219 studies were included. Prospective studies comprised 89/219 (41%), and of these, the number of randomised phase II and III trials were 5/89 (6%) and 3/89 (3%) respectively. Of all the phase II and III trials, 18/24 (75%) were conducted at a single PBT centre. Over one-third of authors recommended an increase in length of follow up. Research design and/or findings were poorly reported in 74/89 (83%) of prospective studies. Patient reported outcomes were assessed in only 19/89 (21%) of prospective studies.

CONCLUSIONS

Prospective randomised evidence for PBT is limited. The set-up of national PBT services in several countries provides an opportunity to guide the optimal design of prospective studies, including RCTs, to evaluate the benefits of PBT across various disease sites. Collaboration between PBT centres, both nationally and internationally, would increase potential for the generation of practice changing evidence. There is a need to facilitate and guide the collection and analysis of meaningful outcome data, including late toxicities and patient reported QoL.

Quality of life in prostate cancer patients receiving particle radiotherapy: A review of the literature

Proton and carbon ion radiotherapy for the treatment of prostate cancer is associated with a lower incidence of adverse events than conventional radiotherapy. There are few reports on the quality of life of patients treated with particle therapy, and limited patient-reported outcomes. Analysis of quality of life is important for patients treated with radiotherapy alone or in combination with hormonal therapy, and long-term results, dose fractionation and costs need to be included in the analysis. This information might help both clinical decision-making and selection of appropriate treatments according to the individual needs of patients. This study reviews the literature on the quality of life and outcomes of patients treated with particle therapy, and discusses future directions.

Proton beam therapy for renal pelvis and ureter cancer: A report of 5 cases and a literature review

Standard treatment for localized renal pelvis and ureter cancer is surgery. Previously, the primary role of radiation therapy (RT) in cancer treatment was to control pain and hemostasis as palliative or as adjuvant therapy following surgery. In this report, we describe 5 patients with the disease treated with proton beam therapy (PBT) as curative treatment. Between September 2009 and July 2013, 5 males with renal pelvis (n=3) or ureter (n=2) cancer were treated by PBT with hypofractionated [72.6 Gy relative biological effectiveness (RBE)/22 fractions] or conventional [64-66 Gy (RBE)/32-33 fractions] fractionation. The median patient age was 72 years (range, 59-85 years). Three patients were deemed unfit for surgery. Local hypofractionated PBT was performed in 2 patients with T1-2N0M0 diseases, while prophylactic lymph node irradiation using a patch irradiation technique was performed for the remaining 3 patients, who had T3-4 disease. Two patients with T3-4 disease received chemotherapy prior to definitive PBT. No serious acute or late toxicities were observed in any patient. Local tumor control was achieved in 3 patients (60%); however, distant metastases were observed in 2 patients. Four of the five patients (80%) evaluated in the present study survived for >3 years. The data is limited; however, PBT appears to be a potential option for patients with renal pelvis or ureter cancer, especially for those who are unsuitable for radical surgery.

Potential skin morbidity reduction with intensity-modulated proton therapy for breast cancer with nodal involvement

Background: Different modern radiation therapy treatment solutions for breast cancer (BC) and regional nodal irradiation (RNI) have been proposed. In this study, we evaluate the potential reduction in radiation-induced skin morbidity obtained by intensity modulated proton therapy (IMPT) compared with intensity modulated photon therapy (IMXT) for left-side BC and RNI. Material and Methods: Using CT scans from 10 left-side BC patients, treatment plans were generated using IMXT and IMPT techniques. A dose of 50 Gy (or Gy [RBE] for IMPT) was prescribed to the target volume (involved breast, the internal mammary, supraclavicular, and infraclavicular nodes). Two single filed optimization IMPT (IMPT₁ and IMPT₂) plans were calculated without and with skin optimization. For each technique, skin dose-metrics were extracted and normal tissue complication probability (NTCP) models from the literature were employed to estimate the risk of radiation-induced skin morbidity. NTCPs for relevant organs-at-risk (OARs) were also considered for reference. The non-parametric Anova (Friedman matched-pairs signed-rank test) was used for comparative analyses. Results: IMPT improved target coverage and dose homogeneity even if the skin was included into optimization strategy (HI_IMPT2 = 0.11 vs. HI_IMXT = 0.22 and CI_IMPT2 = 0.96 vs. CI_IMXT = 0.82, p < .05). A significant relative skin risk reduction (RR = NTCP_IMPT/NTCP_IMXT) was obtained with IMPT₂ including the skin in the optimization with a RR reduction ranging from 0.3 to 0.9 depending on the analyzed skin toxicity endpoint/model. Both IMPT plans attained significant OARs dose sparing compared with IMXT. As expected, the heart and lung doses were significantly reduced using IMPT. Accordingly, IMPT always provided lower NTCP values. Conclusions: IMPT guarantees optimal target coverage, OARs sparing, and simultaneously minimizes the risk of skin morbidity. The applied model-based approach supports the potential clinical relevance of IMPT for left-side BC and RNI and might be relevant for the setup of cost-effectiveness evaluation strategies based on NTCP predictions, as well as for establishing patient selection criteria.

The Use of Radiation Therapy for the Treatment of Malignant Pleural Mesothelioma: Expert Opinion from the National Cancer Institute Thoracic Malignancy Steering Committee, International Association for the Study of Lung Cancer, and Mesothelioma Applied Research Foundation

INTRODUCTION

Detailed guidelines regarding the use of radiation therapy for malignant pleural mesothelioma (MPM) are currently lacking because of the rarity of the disease, the wide spectrum of clinical presentations, and the paucity of high-level data on individual treatment approaches.

METHODS

In March 2017, a multidisciplinary meeting of mesothelioma experts was cosponsored by the U.S. National Cancer Institute, International Association for the Study of Lung Cancer Research, and Mesothelioma Applied Research Foundation. Among the outcomes of this conference was the foundation of detailed, multidisciplinary consensus guidelines.

RESULTS

Here we present consensus recommendations on the use of radiation therapy for MPM in three discrete scenarios: (1) hemithoracic radiation therapy to be used before or after extrapleural pneumonectomy; (2) hemithoracic radiation to be used as an adjuvant to lung-sparing procedures (i.e., without pneumonectomy); and (3) palliative radiation therapy for focal symptoms caused by the disease. We discuss appropriate simulation techniques, treatment volumes, dose fractionation regimens, and normal tissue constraints. We also assess the role of particle beam therapy, specifically, proton beam therapy, for MPM.

CONCLUSION

The recommendations provided in this consensus statement should serve as important guidelines for developing future clinical trials of treatment approaches for MPM.