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International Journal of Radiation... Sep 2021Proton therapy is a limited resource that is not available to all patients who may benefit from it. We investigated combined proton-photon treatments, in which some...
PURPOSE
Proton therapy is a limited resource that is not available to all patients who may benefit from it. We investigated combined proton-photon treatments, in which some fractions are delivered with protons and the remaining fractions with photons, as an approach to maximize the benefit of limited proton therapy resources at a population level.
METHODS AND MATERIALS
To quantify differences in normal-tissue complication probability (NTCP) between protons and photons, we considered a cohort of 45 patients with head and neck cancer for whom intensity modulated radiation therapy and intensity modulated proton therapy plans were previously created, in combination with NTCP models for xerostomia and dysphagia considered in the Netherlands for proton patient selection. Assuming limited availability of proton slots, we developed methods to optimally assign proton fractions in combined proton-photon treatments to minimize the average NTCP on a population level. The combined treatments were compared with patient selection strategies in which patients are assigned to single-modality proton or photon treatments.
RESULTS
There is a benefit of combined proton-photon treatments compared with patient selection, owing to the nonlinearity of NTCP functions; that is, the initial proton fractions are the most beneficial, whereas additional proton fractions have a decreasing benefit when a flatter part of the NTCP curve is reached. This effect was small for the patient cohort and NTCP models considered, but it may be larger if dose-response relationships are better known. In addition, when proton slots are limited, patient selection methods face a trade-off between leaving slots unused and blocking slots for future patients who may have a larger benefit. Combined proton-photon treatments with flexible proton slot assignment provide a method to make optimal use of all available resources.
CONCLUSIONS
Combined proton-photon treatments allow for better use of limited proton therapy resources. The benefit over patient selection schemes depends on the NTCP models and the dose differences between protons and photons.
Topics: Deglutition Disorders; Head and Neck Neoplasms; Humans; Photons; Proton Therapy; Radiotherapy, Intensity-Modulated; Xerostomia
PubMed: 33848609
DOI: 10.1016/j.ijrobp.2021.03.054 -
Cancer Communications (London, England) Oct 2019Proton therapy offers dominant advantages over photon therapy due to the unique depth-dose characteristics of proton, which can cause a dramatic reduction in normal... (Review)
Review
Proton therapy offers dominant advantages over photon therapy due to the unique depth-dose characteristics of proton, which can cause a dramatic reduction in normal tissue doses both distal and proximal to the tumor target volume. In turn, this feature may allow dose escalation to the tumor target volume while sparing the tumor-neighboring susceptible organs at risk, which has the potential to reduce treatment toxicity and improve local control rate, quality of life and survival. Some dosimetric studies in various cancers have demonstrated the advantages over photon therapy in dose distributions. Further, it has been observed that proton therapy confers to substantial clinical advantage over photon therapy in head and neck, breast, hepatocellular, and non-small cell lung cancers. As such, proton therapy is regarded as the standard modality of radiotherapy in many pediatric cancers from the technical point of view. However, due to the limited clinical evidence, there have been concerns about the high cost of proton therapy from an economic point of view. Considering the treatment expenses for late radiation-induced toxicities, cost-effective analysis in many studies have shown that proton therapy is the most cost-effective option for brain, head and neck and selected breast cancers. Additional studies are warranted to better unveil the cost-effective values of proton therapy and to develop newer ways for better protection of normal tissues. This review aims at reviewing the recent studies on proton therapy to explore its benefits and cost-effectiveness in cancers. We strongly believe that proton therapy will be a common radiotherapy modality for most types of solid cancers in the future.
Topics: Cost-Benefit Analysis; Humans; Neoplasms; Proton Therapy
PubMed: 31640788
DOI: 10.1186/s40880-019-0407-3 -
Pediatric Blood & Cancer Jul 2018Proton therapy is a form of particle therapy with physical properties that provide a superior dose distribution compared to photons. The ability to spare healthy,... (Review)
Review
Proton therapy is a form of particle therapy with physical properties that provide a superior dose distribution compared to photons. The ability to spare healthy, developing tissues from low dose radiation with proton therapy is well known. The capability to decrease radiation exposure for children has been lauded as an important advance in pediatric cancer care, particularly for central nervous system (CNS) tumors. Favorable clinical outcomes have been reported and justify the increased cost and burden of this therapy. In this review, we summarize the current literature for proton therapy for pediatric CNS malignancies, with a focus on clinical outcomes to date.
Topics: Central Nervous System Neoplasms; Child; Humans; Proton Therapy; Treatment Outcome
PubMed: 29630784
DOI: 10.1002/pbc.27046 -
Chinese Clinical Oncology Aug 2016Proton therapy (PT) for prostate cancer has been a subject of controversy over the past two decades. Because of its dosimetric advantages when compared to conventional... (Review)
Review
Proton therapy (PT) for prostate cancer has been a subject of controversy over the past two decades. Because of its dosimetric advantages when compared to conventional radiation, PT has the potential to improve the therapeutic ratio in the management of prostate cancer by decreasing toxicity and improving disease control. Nevertheless, its higher costs and the current lack of level I evidence documenting improved clinical outcomes have led some to question its cost-effectiveness. A number of new PT centers have been built over the past decade, leading many stakeholders, including patients, physicians, and insurers, to demand comparative effectiveness data to support its current use. In this review, we summarize the results of recently published studies that support the safety and efficacy of PT in the treatment of prostate cancer. We also review the available cost-effectiveness data for PT and discuss the future of PT, including the current randomized trial comparing PT to intensity-modulated radiation therapy and the need for additional research that may help to establish the relative benefit of PT when compared to photon-based radiation therapy.
Topics: Humans; Male; Prostatic Neoplasms; Proton Therapy
PubMed: 27558255
DOI: 10.21037/cco.2016.08.02 -
Current Oncology (Toronto, Ont.) Feb 2023Proton therapy is a promising therapeutic modality with unique physical properties that allow for abrupt dose fall-off distal to the target of interest, thereby sparing... (Review)
Review
Proton therapy is a promising therapeutic modality with unique physical properties that allow for abrupt dose fall-off distal to the target of interest, thereby sparing nearby organs at risk. A number of studies have identified the utility of proton radiation in mitigating treatment related sequelae for patients with locally advanced breast cancers. Thus, in the following review, we highlight clinical and technical considerations for proton radiotherapy delivery in patients with locally advanced breast cancer.
Topics: Humans; Female; Breast Neoplasms; Proton Therapy; Protons
PubMed: 36975432
DOI: 10.3390/curroncol30030219 -
BMC Gastroenterology Aug 2023Hepatocellular carcinoma (HCC) with bile duct invasion (BDI) (BDIHCC) has a poor prognosis. Moreover, due to the paucity of reports, there is no consensus regarding...
AIM
Hepatocellular carcinoma (HCC) with bile duct invasion (BDI) (BDIHCC) has a poor prognosis. Moreover, due to the paucity of reports, there is no consensus regarding optimal management of this clinical condition yet. The aim of this study was to clarify the efficacy and safety of proton beam therapy (PBT) for BDIHCC.
METHODS
Between 2009 and 2018, 15 patients with BDIHCC underwent PBT at our institution. The overall survival (OS), local control (LC), and progression-free survival (PFS) curves were constructed using the Kaplan-Meier method. Toxicities were assessed using the Common Terminology Criteria of Adverse Events version 4.0.
RESULTS
The median follow-up time was 23.4 months (range, 7.9-54.3). The median age was 71 years (range, 58-90 years). Many patients were Child A (n = 8, 53.3%) and most had solitary tumors (n = 11, 73.3%). Additionally, most patients had central type BDI (n = 11, 73%). The median tumor size was 4.0 cm (range, 1.5-8.0 cm). The 1-, 2-, and 3-year OS rates were 80.0%, 58.7% and 40.2%, respectively, and the corresponding LC and PFS rates were 93.3%, 93.3%, and 74.7% and 72.7%, 9.7%, and 0.0%, respectively. Acute grade 1/2 dermatitis (n = 7, 46.7%), and grades 2 (n = 1, 6.7%) and 3 (n = 1, 6.7%) cholangitis were observed. Late toxicities such as grade 3 gastric hemorrhage and pleural effusion were observed. No toxicities of grade 4 or higher were observed.
CONCLUSIONS
PBT was feasible with tolerable toxicities for the treatment of BDIHCC.
Topics: Aged; Humans; Bile Ducts; Carcinoma, Hepatocellular; Liver Neoplasms; Progression-Free Survival; Proton Therapy; Middle Aged; Aged, 80 and over
PubMed: 37537527
DOI: 10.1186/s12876-023-02897-y -
Neurosurgery May 2019Radiation therapy plays a significant role in management of benign and malignant diseases of the central nervous system. Patients may be at risk of acute and late... (Review)
Review
Radiation therapy plays a significant role in management of benign and malignant diseases of the central nervous system. Patients may be at risk of acute and late toxicity from radiation therapy due to dose deposition in critical normal structures. In contrast to conventional photon delivery techniques, proton therapy is characterized by Bragg peak dose deposition which results in decreased exit dose beyond the target and greater sparing of normal structure which may reduce the rate of late toxicities from treatment. Dosimetric studies have demonstrated reduced dose to normal structures using proton therapy as compared to photon therapy. In addition, clinical studies are being reported demonstrating safety, feasibility, and low rates of acute toxicity. Technical challenges in proton therapy remain, including full understanding of depth of proton penetration and the biological activity in the distal Bragg peak. In addition, longer clinical follow-up is required to demonstrate reduction in late toxicities as compared to conventional photon-based radiation techniques. In this review, we summarize the current clinical literature and areas of active investigation in proton therapy for adult central nervous system malignancies.
Topics: Adult; Central Nervous System Neoplasms; Humans; Proton Therapy
PubMed: 30476191
DOI: 10.1093/neuros/nyy454 -
Chinese Clinical Oncology Aug 2016This review will focus on the indications, clinical experience, and technical considerations of proton beam radiation therapy in the treatment of patients with breast... (Review)
Review
This review will focus on the indications, clinical experience, and technical considerations of proton beam radiation therapy in the treatment of patients with breast cancer. For patients with early stage disease, proton therapy delivers less dose to non-target breast tissue for patients receiving partial breast irradiation (PBI) therapy, which may result in improved cosmesis but requires further investigation. For patients with locally advanced breast cancer requiring treatment to the regional lymph nodes, proton therapy allows for an improved dosimetric profile compared with conventional photon and electron techniques. Early clinical results demonstrate acceptable toxicity. The possible reduction in cardiopulmonary events as a result of reduced dose to organs at risk will be tested in a randomized control trial of protons vs. photons.
Topics: Breast Neoplasms; Female; Humans; Proton Therapy
PubMed: 27558253
DOI: 10.21037/cco.2016.06.04 -
Physics in Medicine and Biology Oct 2021Anatomical changes during proton therapy require rapid treatment plan adaption to mitigate the associated dosimetric impact. This in turn requires a highly efficient...
Anatomical changes during proton therapy require rapid treatment plan adaption to mitigate the associated dosimetric impact. This in turn requires a highly efficient workflow that minimizes the time between imaging and delivery. At the Paul Scherrer Institute, we have developed an online adaptive workflow, which is specifically designed for treatments in the skull-base/cranium, with the focus set on simplicity and minimizing changes to the conventional workflow. The dosimetric and timing performance of this daily adaptive proton therapy (DAPT) workflow has been experimentally investigated using an in-house developed DAPT software and specifically developed anthropomorphic phantom. After a standard treatment preparation, which includes the generation of a template plan, the treatment can then be adapted each day, based on daily imaging acquired on an in-room CT. The template structures are then rigidly propagated to this CT and the daily plan is fully re-optimized using the same field arrangement, DVH constraints and optimization settings of the template plan. After a dedicated plan QA, the daily plan is delivered. To minimize the time between imaging and delivery, clinically integrated software for efficient execution of all online adaption steps, as well as tools for comprehensive and automated QA checks, have been developed. Film measurements of an end-to-end validation of a multi-fraction DAPT treatment showed high agreement to the calculated doses. Gamma pass rates with a 3%/3 mm criteria were >92% when comparing the measured dose to the template plan. Additionally, a gamma pass rate >99% was found comparing measurements to the Monte Carlo dose of the daily plans reconstructed from the logfile, accumulated over the delivered fractions. With this, we experimentally demonstrate that the described adaptive workflow can be delivered accurately in a timescale similar to a standard delivery.
Topics: Phantoms, Imaging; Platelet Aggregation Inhibitors; Proton Therapy; Radiotherapy Dosage; Radiotherapy Planning, Computer-Assisted; Radiotherapy, Intensity-Modulated
PubMed: 34587589
DOI: 10.1088/1361-6560/ac2b84 -
Clinical Oncology (Royal College of... Aug 2017As an alternative to conventional photon-based radiotherapy, radiation with protons is recognised to offer considerable advantages. Today, central nervous system... (Review)
Review
As an alternative to conventional photon-based radiotherapy, radiation with protons is recognised to offer considerable advantages. Today, central nervous system tumours, various sarcomatous tumours, childhood cancer and head and neck tumours are commonly treated with proton therapy. This review evaluates current data from clinical and dosimetric trials on the treatment of selected sarcomatous tumours like rhabdomyosarcoma, osteosarcoma, chordoma, chondrosarcoma and Ewing sarcoma. Special considerations for paediatric tumours and future prospects of proton therapy are outlined. Proton therapy is already an internal part in the multidisciplinary management of childhood sarcomas in contiguity to sensitive structures, especially at the base of skull, spine and pelvis. It offers special advantages for tumours requiring high-precision radiotherapy, particularly when total resection seems not feasible. Previous and ongoing research is generating evidence for the benefit of protons in sarcoma patients. Up to now, proton therapy has been safely applied with encouraging results. For future research, prospective, multi-institutional, large registries are required to answer open questions. Modern radiotherapy techniques, such as pencil beam scanning and intensity modulation are increasingly established in proton therapy. More research is needed to understand protons' limitations and potential.
Topics: Humans; Prospective Studies; Proton Therapy; Sarcoma
PubMed: 28506520
DOI: 10.1016/j.clon.2017.04.034