scholarly journals First Evaluation of Temporal and Spatial Fractionation in Proton Minibeam Radiation Therapy of Glioma-Bearing Rats

Cancers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 4865
Author(s):  
Annaïg Bertho ◽  
Ramon Ortiz ◽  
Marjorie Juchaux ◽  
Cristèle Gilbert ◽  
Charlotte Lamirault ◽  
...  

(1) Background: Proton minibeam radiation therapy (pMBRT) is a new radiotherapy technique using spatially modulated narrow proton beams. pMBRT results in a significantly reduced local tissue toxicity while maintaining or even increasing the tumor control efficacy as compared to conventional radiotherapy in small animal experiments. In all the experiments performed up to date in tumor bearing animals, the dose was delivered in one single fraction. This is the first assessment on the impact of a temporal fractionation scheme on the response of glioma-bearing animals to pMBRT. (2) Methods: glioma-bearing rats were irradiated with pMBRT using a crossfire geometry. The response of the irradiated animals in one and two fractions was compared. An additional group of animals was also treated with conventional broad beam irradiations. (3) Results: pMBRT delivered in two fractions at the biological equivalent dose corresponding to one fraction resulted in the highest median survival time, with 80% long-term survivors free of tumors. No increase in local toxicity was noted in this group with respect to the other pMBRT irradiated groups. Conventional broad beam irradiations resulted in the most severe local toxicity. (4) Conclusion: Temporal fractionation increases the therapeutic index in pMBRT and could ease the path towards clinical trials.

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Enis Tinjak ◽  
Velda Smajlbegović ◽  
Adnan Beganović ◽  
Mirjana Ristanić ◽  
Halil Ćorović ◽  
...  

Introduction: Radiation therapy has long played an integral role in the manage¬ment of locally advanced head and neck cancer (HNC), both for organ preservation and to improve tumor control in the postoperative setting. The aim of this research is to investigate the effects of adaptive radiotherapy on dosimetric, clinical, and toxicity outcomes for patients with head and neck cancer undergoing radiation therapy treatment. Many sources have reported volume reductions in the primary target, nodal volumes, and parotid glands over treatment, which may result in unintended dosimetric changes affecting the side effect profile and even efficacy of the treatment. Adaptive radiotherapy (ART) is an interesting treatment paradigm that has been developed to directly adjust to these changes.Material and methods: This research contains the results of 15 studies, including clinical trials, randomized prospective and retrospective studies. The researches analyze the impact of radiation therapy on changes in tumor volume and the relationship with planned radiation dose delivery, as well as the possibility of using adaptive radiotherapy in response to identified changes. Also, medical articles and abstracts that are closely related to the title of adaptive radiotherapy were researched.Results: The application of ART significantly improved the quality of life of patients with head and neck cancer, as well as two-year locoregional control of the disease. The average time to apply ART is the middle of the treatment course approximately 17 to 20 fractions of the treatment.Conclusion: Based on systematic review of the literature, evidence based changes in target volumes and dose reduction at OAR, adaptive radiotherapy is recommended treatment for most of the patients with head and neck cancer with the support of image-guided radiotherapy.


2009 ◽  
Vol 27 (15_suppl) ◽  
pp. 7591-7591
Author(s):  
D. Nader ◽  
P. Ketterl ◽  
D. Kelly ◽  
J. Flynn ◽  
J. J. Stark ◽  
...  

7591 Background: NSCLC patients (pts) with clinically significant endobronchial obstruction have a poor prognosis and quality of life in both locally advanced and metastatic stages of disease. Radiation therapy (RTx) in conjunction with chemotherapy (CTx) improves survival compared to either modality alone but produces greater toxicity and morbidity. Significant clinical benefit with respect to disease management and quality of life could be realized with improved methods for controlling obstructing endobronchial lesions. The hypothesis for this study is that optimal clinical control of endobronchial lesions can be achieved by intratumoral injection of a drug with both clinical activity against NSCLC and synergy with RTx. Cisplatin (CPt), an active agent in NSCLC and a known radiosensitizer is an ideal drug for this objective. Thus, the goal of this exploratory study was to determine the clinical efficacy and tolerance to intratumoral CPt injection in combination with HDR brachytherapy (BTx) in NSCLC patients with obstructing endobronchial lesions. Methods: NSCLC pts (n=16) with > 75% endoluminal obstruction of a main or lobar airway were evaluated. Intratumoral CTx consisted of CPt (1 mg/ml; 0.5–2.0 ml/session) injected into the entire visible tumor through a flexible 21 gauge needle through the bronchoscope. BTx was given as 500 cGy/session at one cm diameter for 4 sessions concomitant with CTx. Results: All pts completed the entire 4 sessions of planned local therapy. There was complete resolution of injected lesions in 14/16 pts confirmed bronchoscopically and cytologically. In the other 2 pts, necrotic tissue occupying < 10 and 20% of the airway, cytologically negative for tumor was seen. There were no adverse events or complications related to bronchoscopy or local CTx. Conclusions: The results of this study demonstrate that intratumoral administration of CPt, as an adjunct to endobronchial BTx for the management of endobronchial obstructing lesions in patients with NSCLC is safe and effective. This approach offers the possibility of superior local tumor control while reducing toxicity to normal lung and esophagus as compared to conventional external beam radiation therapy modalities. Further studies evaluating the impact of this approach on survival and quality of life are warranted. No significant financial relationships to disclose.


Cancers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 936
Author(s):  
Laura Eling ◽  
Audrey Bouchet ◽  
Alexandre Ocadiz ◽  
Jean-François Adam ◽  
Sarvenaz Kershmiri ◽  
...  

Delivery of high-radiation doses to brain tumors via multiple arrays of synchrotron X-ray microbeams permits huge therapeutic advantages. Brain tumor (9LGS)-bearing and normal rats were irradiated using a conventional, homogeneous Broad Beam (BB), or Microbeam Radiation Therapy (MRT), then studied by behavioral tests, MRI, and histopathology. A valley dose of 10 Gy deposited between microbeams, delivered by a single port, improved tumor control and median survival time of tumor-bearing rats better than a BB isodose. An increased number of ports and an accumulated valley dose maintained at 10 Gy delayed tumor growth and improved survival. Histopathologically, cell death, vascular damage, and inflammatory response increased in tumors. At identical valley isodose, each additional MRT port extended survival, resulting in an exponential correlation between port numbers and animal lifespan (r2 = 0.9928). A 10 Gy valley dose, in MRT mode, delivered through 5 ports, achieved the same survival as a 25 Gy BB irradiation because of tumor dose hot spots created by intersecting microbeams. Conversely, normal tissue damage remained minimal in all the single converging extratumoral arrays. Multiport MRT reached exceptional ~2.5-fold biological equivalent tumor doses. The unique normal tissue sparing and therapeutic index are eminent prerequisites for clinical translation.


2020 ◽  
Vol 26 (1) ◽  
pp. 22-26 ◽  
Author(s):  
Tryggve Lundar ◽  
Bernt Johan Due-Tønnessen ◽  
Radek Frič ◽  
Petter Brandal ◽  
Paulina Due-Tønnessen

OBJECTIVEEpendymoma is the third most common posterior fossa tumor in children; however, there is a lack of long-term follow-up data on outcomes after surgical treatment of posterior fossa ependymoma (PFE) in pediatric patients. Therefore, the authors sought to investigate the long-term outcomes of children treated for PFE at their institution.METHODSThe authors performed a retrospective analysis of outcome data from children who underwent treatment for PFE and survived for at least 5 years.RESULTSThe authors identified 22 children (median age at the time of surgery 3 years, range 0–18 years) who underwent primary tumor resection of PFE during the period from 1945 to 2014 and who had at least 5 years of observed survival. None of these 22 patients were lost to follow-up, and they represent the long-term survivors (38%) from a total of 58 pediatric PFE patients treated. Nine (26%) of the 34 children treated during the pre-MRI era (1945–1986) were long-term survivors, while the observed 5-year survival rate in the children treated during the MRI era (1987–2014) was 13 (54%) of 24 patients. The majority of patients (n = 16) received adjuvant radiotherapy, and 4 of these received proton-beam irradiation. Six children had either no adjuvant treatment (n = 3) or only chemotherapy as adjuvant treatment (n = 3). Fourteen patients were alive at the time of this report. According to MRI findings, all of these patients were tumor free except 1 patient (age 78 years) with a known residual tumor after 65 years of event-free survival.Repeat resections for residual or recurrent tumor were performed in 9 patients, mostly for local residual disease with progressive clinical symptoms; 4 patients underwent only 1 repeated resection, whereas 5 patients each had 3 or more resections within 15 years after their initial surgery. At further follow-up, 5 of the patients who underwent a second surgery were found to be dead from the disease with or without undergoing additional resections, which were performed from 6 to 13 years after the second procedure. The other 4 patients, however, were tumor free on the latest follow-up MRI, performed from 6 to 27 years after the last resection. Hence, repeated surgery appears to increase the chance of tumor control in some patients, along with modern (proton-beam) radiotherapy. Six of 8 patients with more than 20 years of survival are in a good clinical condition, 5 of them in full-time work and 1 in part-time work.CONCLUSIONSPediatric PFE occurs mostly in young children, and there is marked risk for local recurrence among 5-year survivors even after gross-total resection and postoperative radiotherapy. Repeated resections are therefore an important part of treatment and may lead to persistent tumor control. Even though the majority of children with PFE die from their tumor disease, some patients survive for more than 50 years with excellent functional outcome and working capacity.


Cancers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1889
Author(s):  
Arthur Bongrand ◽  
Charbel Koumeir ◽  
Daphnée Villoing ◽  
Arnaud Guertin ◽  
Ferid Haddad ◽  
...  

Proton therapy (PRT) is an irradiation technique that aims at limiting normal tissue damage while maintaining the tumor response. To study its specificities, the ARRONAX cyclotron is currently developing a preclinical structure compatible with biological experiments. A prerequisite is to identify and control uncertainties on the ARRONAX beamline, which can lead to significant biases in the observed biological results and dose–response relationships, as for any facility. This paper summarizes and quantifies the impact of uncertainty on proton range, absorbed dose, and dose homogeneity in a preclinical context of cell or small animal irradiation on the Bragg curve, using Monte Carlo simulations. All possible sources of uncertainty were investigated and discussed independently. Those with a significant impact were identified, and protocols were established to reduce their consequences. Overall, the uncertainties evaluated were similar to those from clinical practice and are considered compatible with the performance of radiobiological experiments, as well as the study of dose–response relationships on this proton beam. Another conclusion of this study is that Monte Carlo simulations can be used to help build preclinical lines in other setups.


2021 ◽  
pp. 019459982110104
Author(s):  
Carly E. A. Barbon ◽  
Douglas B. Chepeha ◽  
Andrew J. Hope ◽  
Melanie Peladeau-Pigeon ◽  
Ashley A. Waito ◽  
...  

The current standard for the treatment of oropharynx cancers is radiation therapy. However, patients are frequently left with dysphagia characterized by penetration-aspiration (impaired safety) and residue (impaired efficiency). Although thickened liquids are commonly used to manage dysphagia, we lack evidence to guide the modification of liquids for clinical benefit in the head and neck cancer population. The objective of this study was to assess the impact of slightly and mildly thick liquids on penetration-aspiration and residue in 12 patients with oropharyngeal cancer who displayed penetration-aspiration on thin liquid within 3 to 6 months after completion of radiotherapy. Significantly fewer instances of penetration-aspiration were seen with slightly and mildly thick liquids as compared with thin ( P < .05). No differences were found across stimuli in the frequency of residue. Patients with oropharyngeal cancers who present with post–radiation therapy dysphagia involving penetration-aspiration on thin liquids may benefit from slightly and mildly thick liquids without risk of worse residue.


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