International Journal of Particle Therapy最新文献

{"title":"NRG Oncology Survey of Monte Carlo Dose Calculation Use in US Proton Therapy Centers.","authors":"Liyong Lin,&nbsp;Paige A Taylor,&nbsp;Jiajian Shen,&nbsp;Jatinder Saini,&nbsp;Minglei Kang,&nbsp;Charles B Simone,&nbsp;Jeffrey D Bradley,&nbsp;Zuofeng Li,&nbsp;Ying Xiao","doi":"10.14338/IJPT-D-21-00004","DOIUrl":"https://doi.org/10.14338/IJPT-D-21-00004","url":null,"abstract":"<p><strong>Purpose/objectives: </strong>Monte Carlo (MC) dose calculation has appeared in primary commercial treatment-planning systems and various in-house platforms. Dual-energy computed tomography (DECT) and metal artifact reduction (MAR) techniques complement MC capabilities. However, no publications have yet reported how proton therapy centers implement these new technologies, and a national survey is required to determine the feasibility of including MC and companion techniques in cooperative group clinical trials.</p><p><strong>Materials/methods: </strong>A 9-question survey was designed to query key clinical parameters: scope of MC utilization, validation methods for heterogeneities, clinical site-specific imaging guidance, proton range uncertainties, and how implants are handled. A national survey was distributed to all 29 operational US proton therapy centers on 13 May 2019.</p><p><strong>Results: </strong>We received responses from 25 centers (86% participation). Commercial MC was most commonly used for primary plan optimization (16 centers) or primary dose evaluation (18 centers), while in-house MC was used more frequently for secondary dose evaluation (7 centers). Based on the survey, MC was used infrequently for gastrointestinal, genitourinary, gynecology and extremity compared with other more heterogeneous disease sites (<i>P</i> < .007). Although many centers had published DECT research, only 3/25 centers had implemented DECT clinically, either in the treatment-planning system or to override implant materials. Most centers (64%) treated patients with metal implants on a case-by-case basis, with a variety of methods reported. Twenty-four centers (96%) used MAR images and overrode the surrounding tissue artifacts; however, there was no consensus on how to determine metal dimension, materials density, or stopping powers.</p><p><strong>Conclusion: </strong>The use of MC for primary dose calculation and optimization was prevalent and, therefore, likely feasible for clinical trials. There was consensus to use MAR and override tissues surrounding metals but no consensus about how to use DECT and MAR for human tissues and implants. Development and standardization of these advanced technologies are strongly encouraged for vendors and clinical physicists.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"8 2","pages":"73-81"},"PeriodicalIF":1.7,"publicationDate":"2021-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8489489/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39669116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Intensity-Modulated Proton Therapy for Nasopharynx Cancer: 2-year Outcomes from a Single Institution.","authors":"Vonetta M Williams,&nbsp;Upendra Parvathaneni,&nbsp;George E Laramore,&nbsp;Saif Aljabab,&nbsp;Tony P Wong,&nbsp;Jay J Liao","doi":"10.14338/IJPT-20-00057.1","DOIUrl":"https://doi.org/10.14338/IJPT-20-00057.1","url":null,"abstract":"<p><strong>Purpose: </strong>Advances in radiotherapy have improved tumor control and reduced toxicity in the management of nasopharyngeal carcinoma (NPC). Local failure remains a problem for some patients with advanced primary tumors, and toxicities are significant given the large treatment volume and tumor proximity to critical structures, even with modern photon-based radiotherapy. Proton therapy has unique dosimetric advantages, and recent technological advances now allow delivery of intensity-modulated proton therapy (IMPT), which can potentially improve the therapeutic ratio in NPC. We report our 2-year clinical outcomes with IMPT for NPC.</p><p><strong>Materials and methods: </strong>We retrospectively reviewed treatment records of patients with NPC treated with IMPT at our center. Demographics, dosimetry, tumor response, local regional control (LRC), distant metastasis, overall survival, and acute and late toxicity outcomes were reviewed. Analyses were performed with descriptive statistics and Kaplan-Meier method. Toxicity was graded per Common Terminology Criteria for Adverse Events (version 4.0).</p><p><strong>Results: </strong>Twenty-six patients were treated from 2015 to 2020. Median age was 48 years (range, 19-73 years), 62% (n = 16) had T3-T4 disease, 92% (n = 24) were node positive, 92% (n = 24) had stage III-IV disease, and 69% (n = 18) had positive results for Epstein-Barr virus. Dose-painted pencil-beam IMPT was used. Most patients (85%; 22 of 26) were treated with 70 Gy(RBE) in 33 fractions once daily; 4 (15%) underwent hyperfractionated accelerated treatment twice daily. All received concurrent cisplatin chemotherapy; 7 (27%) also received induction chemotherapy. All patients (100%) completed the planned radiotherapy, and no acute or late grade 4 or 5 toxicities were observed. At median follow-up of 25 months (range, 4-60), there were 2 local regional failures (8%) and 3 distant metastases (12%). The Kaplan-Meier 2-year LRC, freedom from distant metastasis, and overall survival were 92%, 87%, and 85% respectively.</p><p><strong>Conclusion: </strong>IMPT is feasible in locally advanced NPC with early outcomes demonstrating excellent LRC and favorable toxicity profile. Our data add to the growing body of evidence supporting the clinical use of IMPT for NPC.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"8 2","pages":"28-40"},"PeriodicalIF":1.7,"publicationDate":"2021-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8489486/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39580491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Simultaneous Multiple Liver Metastasis Treated with Pencil Beam Proton Stereotactic Body Radiotherapy (SBRT).","authors":"Neil K Taunk,&nbsp;Brendan Burgdorf,&nbsp;Lei Dong,&nbsp;Edgar Ben-Josef","doi":"10.14338/IJPT-20-00085.1","DOIUrl":"https://doi.org/10.14338/IJPT-20-00085.1","url":null,"abstract":"<p><p>Compared with photon stereotactic body radiotherapy (SBRT) plans that may have to use many more penetrating x-ray beams for each isocenter, proton SBRT with ultrahypofractionated doses use fewer beam angles and offer significantly reduced low-dose radiation bath to normal liver tissue. We demonstrate techniques to deliver safe and effective proton SBRT, where planning and organ motion complexity further increased with multiple liver lesions. For treatment planning, we recommend robust and logical beam angles, avoiding devices and encouraging entry perpendicular to the dominant motion, as well as volumetric repainting to mitigate the interplay effect to clinically acceptable levels. This report highlights the significant technical challenges with ultrahypofractionated proton pencil beam scanning liver therapy, how they are managed, and the effectiveness of this treatment.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"8 2","pages":"89-94"},"PeriodicalIF":1.7,"publicationDate":"2021-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8489493/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39669118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Radiotherapeutic Management of Synchronous Prostate and Rectal Cancers Using Proton Beam Therapy.","authors":"Jennifer S Chiang,&nbsp;Nathan Y Yu,&nbsp;Janina T Sheedy,&nbsp;Robin E Hayden,&nbsp;Pamela R Lemish,&nbsp;Nina J Karlin,&nbsp;Nitin Mishra,&nbsp;Terence T Sio","doi":"10.14338/IJPT-20-00087.1","DOIUrl":"https://doi.org/10.14338/IJPT-20-00087.1","url":null,"abstract":"<p><p>Treatment of synchronous prostate and rectal cancers is a rare yet challenging problem with compounded toxicities. We report a case of a 65-year-old man who underwent proton beam therapy (PBT) with concurrent capecitabine and hormonal therapy for his synchronously found prostate (intermediate-risk) and rectal (cT2, N2b, stage IIIB) cancers; he also received low anterior resection. Before PBT, the patient experienced hematochezia. His baseline American Urological Association symptom score was a total of 0, and he was not sexually active. He completed PBT with grade 1 acute toxicities including fatigue, nausea, and increased urinary and bowel frequencies. He also developed mild anemia (10.7), which was resolved. Subsequent surgical pathology showed a pathologic complete response in his rectum. At follow-up of 2.5 years, he remained disease-free on surveillance imaging for both malignancies and reported increased bowel urgency and frequency, minimal urinary leakage when having urgency, and peripheral neuropathy. This case, along with a succinct literature review, demonstrates that PBT can be successful in the definitive treatment of synchronous prostate and rectal cancers with minimal toxicities. Further research is required to evaluate the efficacy and side effect profiles of PBT.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"8 2","pages":"82-88"},"PeriodicalIF":1.7,"publicationDate":"2021-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8489491/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39669117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Consensus Statement on Proton Therapy for Prostate Cancer.","authors":"Curtis M Bryant,&nbsp;Randal H Henderson,&nbsp;R Charles Nichols,&nbsp;William M Mendenhall,&nbsp;Bradford S Hoppe,&nbsp;Carlos E Vargas,&nbsp;Thomas B Daniels,&nbsp;C Richard Choo,&nbsp;Rahul R Parikh,&nbsp;Huan Giap,&nbsp;Jerry D Slater,&nbsp;Neha Vapiwala,&nbsp;William Barrett,&nbsp;Akash Nanda,&nbsp;Mark V Mishra,&nbsp;Seungtaek Choi,&nbsp;Jay J Liao,&nbsp;Nancy P Mendenhall","doi":"10.14338/IJPT-20-00031.1","DOIUrl":"10.14338/IJPT-20-00031.1","url":null,"abstract":"<p><p>Proton therapy is a promising but controversial treatment in the management of prostate cancer. Despite its dosimetric advantages when compared with photon radiation therapy, its increased cost to patients and insurers has raised questions regarding its value. Multiple prospective and retrospective studies have been published documenting the efficacy and safety of proton therapy for patients with localized prostate cancer and for patients requiring adjuvant or salvage pelvic radiation after surgery. The Particle Therapy Co-Operative Group (PTCOG) Genitourinary Subcommittee intends to address current proton therapy indications, advantages, disadvantages, and cost effectiveness. We will also discuss the current landscape of clinical trials. This consensus report can be used to guide clinical practice and research directions.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"8 2","pages":"1-16"},"PeriodicalIF":1.7,"publicationDate":"2021-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8489490/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39580489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Radiation-Induced Lymphopenia Risks of Photon Versus Proton Therapy for Esophageal Cancer Patients.","authors":"Saba Ebrahimi,&nbsp;Gino Lim,&nbsp;Amy Liu,&nbsp;Steven H Lin,&nbsp;Susannah G Ellsworth,&nbsp;Clemens Grassberger,&nbsp;Radhe Mohan,&nbsp;Wenhua Cao","doi":"10.14338/IJPT-20-00086","DOIUrl":"https://doi.org/10.14338/IJPT-20-00086","url":null,"abstract":"<p><strong>Purpose: </strong>To assess possible differences in radiation-induced lymphocyte depletion for esophageal cancer patients being treated with the following 3 treatment modalities: intensity-modulated radiation therapy (IMRT), passive scattering proton therapy (PSPT), and intensity-modulated proton therapy (IMPT).</p><p><strong>Methods and materials: </strong>We used 2 prediction models to estimate lymphocyte depletion based on dose distributions. Model I used a piecewise linear relationship between lymphocyte survival and voxel-by-voxel dose. Model II assumes that lymphocytes deplete exponentially as a function of total delivered dose. The models can be fitted using the weekly absolute lymphocyte counts measurements collected throughout treatment. We randomly selected 45 esophageal cancer patients treated with IMRT, PSPT, or IMPT at our institution (15 per modality) to demonstrate the fitness of the 2 models. A different group of 10 esophageal cancer patients who had received PSPT were included in this study of in silico simulations of multiple modalities. One IMRT and one IMPT plan were created, using our standards of practice for each modality, as competing plans to the existing PSPT plan for each patient. We fitted the models by PSPT plans used in treatment and predicted absolute lymphocyte counts for IMRT and IMPT plans.</p><p><strong>Results: </strong>Model validation on each modality group of patients showed good agreement between measured and predicted absolute lymphocyte counts nadirs with mean squared errors from 0.003 to 0.023 among the modalities and models. In the simulation study of IMRT and IMPT on the 10 PSPT patients, the average predicted absolute lymphocyte count (ALC) nadirs were 0.27, 0.35, and 0.37 K/μL after IMRT, PSPT, and IMPT treatments using Model I, respectively, and 0.14, 0.22, and 0.33 K/μL using Model II.</p><p><strong>Conclusions: </strong>Proton plans carried a lower predicted risk of lymphopenia after the treatment course than did photon plans. Moreover, IMPT plans outperformed PSPT in terms of predicted lymphocyte preservation.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"8 2","pages":"17-27"},"PeriodicalIF":1.7,"publicationDate":"2021-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8489492/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39580490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Proton Beam Therapy in the Treatment of Periorbital Malignancies.","authors":"Nicholas J Damico,&nbsp;Anna K Wu,&nbsp;Michael Z Kharouta,&nbsp;Tal Eitan,&nbsp;Rajesh Pidikiti,&nbsp;Frederick B Jesseph,&nbsp;Mark Smith,&nbsp;Christian Langmack,&nbsp;Diana L Mattson,&nbsp;Donald Dobbins,&nbsp;David B Mansur,&nbsp;Mitchell X Machtay,&nbsp;Jennifer A Dorth,&nbsp;Serah Choi,&nbsp;Min Yao,&nbsp;Aashish D Bhatt","doi":"10.14338/IJPT-20-00025.1","DOIUrl":"https://doi.org/10.14338/IJPT-20-00025.1","url":null,"abstract":"<p><strong>Purpose: </strong>Periorbital tumor location presents a significant challenge with 3-dimensional conformal radiation therapy or intensity modulated radiation therapy due to high tumor dose needed in the setting of close proximity to orbital structures with lower tolerance. Proton beam therapy (PBT) is felt to be an effective modality in such cases due to its sharp dose gradient.</p><p><strong>Materials and methods: </strong>We reviewed our institutional PBT registry and identified 17 patients with tumor epicenters within 2 cm of the eye and optic apparatus treated with passive scatter PBT with comparison volumetric arc therapy plans available. Maximum and mean doses to organs at risk of interest, including optic nerves, optic chiasm, lens, eye ball, pituitary, cochlea, lacrimal gland, and surrounding brain, were compared using the paired Wilcoxon signed rank test. Overall survival was determined using the Kaplan-Meier method.</p><p><strong>Results: </strong>Median age was 67. Median follow-up was 19.7 months. Fourteen patients underwent upfront resection and received postoperative radiation and 3 received definitive radiation. One patient received elective neck radiation, 2 underwent reirradiation, and 3 had concurrent chemotherapy. There was a statistically significant reduction in mean dose to the optic nerves and chiasm, brain, pituitary gland, lacrimal glands, and cochlea as well as in the maximum dose to the optic nerves and chiasm, pituitary gland, lacrimal glands, and cochlea with PBT. The 18-month cumulative incidence of local failure was 19.1% and 1-year overall survival was 80.9%.</p><p><strong>Conclusion: </strong>Proton beam therapy resulted in significant dose reductions to several periorbital and optic structures compared with volumetric arc therapy. Proton beam therapy appears to be the optimal radiation modality in such cases to minimize risk of toxicity to periorbital organs at risk.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"7 4","pages":"42-51"},"PeriodicalIF":1.7,"publicationDate":"2021-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8019573/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25570043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"¹⁸Oxygen Substituted Nucleosides Combined with Proton Beam Therapy: Therapeutic Transmutation In Vitro.","authors":"Tyvin Rich,&nbsp;Dongfeng Pan,&nbsp;Mahendra Chordia,&nbsp;Cynthia Keppel,&nbsp;David Beylin,&nbsp;Pavel Stepanov,&nbsp;Mira Jung,&nbsp;Dalong Pang,&nbsp;Scott Grindrod,&nbsp;Anatoly Dritschilo","doi":"10.14338/IJPT-D-20-00036.1","DOIUrl":"https://doi.org/10.14338/IJPT-D-20-00036.1","url":null,"abstract":"<p><strong>Purpose: </strong>Proton therapy precisely delivers radiation to cancers to cause damaging strand breaks to cellular DNA, kill malignant cells, and stop tumor growth. Therapeutic protons also generate short-lived activated nuclei of carbon, oxygen, and nitrogen atoms in patients as a result of atomic transmutations that are imaged by positron emission tomography (PET). We hypothesized that the transition of ¹⁸O to ¹⁸F in an ¹⁸O-substituted nucleoside irradiated with therapeutic protons may result in the potential for combined diagnosis and treatment for cancer with proton therapy.</p><p><strong>Materials and methods: </strong>Reported here is a feasibility study with a therapeutic proton beam used to irradiate H₂ ¹⁸O to a dose of 10 Gy produced by an 85 MeV pristine Bragg peak. PET imaging initiated >45 minutes later showed an ¹⁸F decay signal with T_1/2 of ∼111 minutes.</p><p><strong>Results: </strong>The ¹⁸O to ¹⁸F transmutation effect on cell survival was tested by exposing SQ20B squamous carcinoma cells to physiologic ¹⁸O-thymidine concentrations of 5 μM for 48 hours followed by 1- to 9-Gy graded doses of proton radiation given 24 hours later. Survival analyses show radiation sensitization with a dose modification factor (DMF) of 1.2.</p><p><strong>Conclusions: </strong>These data support the idea of therapeutic transmutation in vitro as a biochemical consequence of proton activation of ¹⁸O to ¹⁸F in substituted thymidine enabling proton radiation enhancement in a cancer cell. ¹⁸O-substituted molecules that incorporate into cancer targets may hold promise for improving the therapeutic window of protons and can be evaluated further for postproton therapy PET imaging.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"7 4","pages":"11-18"},"PeriodicalIF":1.7,"publicationDate":"2021-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8019575/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25572140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"CBCT-Based Adaptive Assessment Workflow for Intensity Modulated Proton Therapy for Head and Neck Cancer.","authors":"Mariluz De Ornelas,&nbsp;Yihang Xu,&nbsp;Kyle Padgett,&nbsp;Ryder M Schmidt,&nbsp;Michael Butkus,&nbsp;Tejan Diwanji,&nbsp;Gus Luciani,&nbsp;Jason Lambiase,&nbsp;Stuart Samuels,&nbsp;Michael Samuels,&nbsp;Nesrin Dogan","doi":"10.14338/IJPT-D-20-00056.1","DOIUrl":"https://doi.org/10.14338/IJPT-D-20-00056.1","url":null,"abstract":"<p><strong>Purpose: </strong>Anatomical changes and patient setup uncertainties during intensity modulated proton therapy (IMPT) of head and neck (HN) cancers demand frequent evaluation of delivered dose. This work investigated a cone-beam computed tomography (CBCT) and deformable image registration based therapy workflow to demonstrate the feasibility of proton dose calculation on synthetic computed tomography (sCT) for adaptive IMPT treatment of HN cancer.</p><p><strong>Materials and methods: </strong>Twenty-one patients with HN cancer were enrolled in this study, a retrospective institutional review board protocol. They had previously been treated with volumetric modulated arc therapy and had daily iterative CBCT. For each patient, robust optimization (RO) IMPT plans were generated using ±3 mm patient setup and ±3% proton range uncertainties. The sCTs were created and the weekly delivered dose was recalculated using an adaptive dose accumulation workflow in which the planning computed tomography (CT) was deformably registered to CBCTs and Hounsfield units transferred from the planning CT. Accumulated doses from ±3 mm/±3% RO-IMPT plans were evaluated using clinical dose-volume constraints for targets (clinical target volume, or CTV) and organs at risk.</p><p><strong>Results: </strong>Evaluation of weekly recalculated dose on sCTs showed that most of the patient plans maintained target dose coverage. The primary CTV remained covered by the V95 > 95% (95% of the volume receiving more than 95% of the prescription dose) worst-case scenario for 84.5% of the weekly fractions. The oral cavity accumulated mean dose remained lower than the worst-case scenario for all patients. Parotid accumulated mean dose remained within the uncertainty bands for 18 of the 21 patients, and all were kept lower than RO-IMPT worst-case scenario for 88.7% and 84.5% for left and right parotids, respectively.</p><p><strong>Conclusion: </strong>This study demonstrated that RO-IMPT plans account for most setup and anatomical uncertainties, except for large weight-loss changes that need to be tracked throughout the treatment course. We showed that sCTs could be a powerful decision tool for adaptation of these cases in order to reduce workload when using repeat CTs.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"7 4","pages":"29-41"},"PeriodicalIF":1.7,"publicationDate":"2021-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8019579/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25570042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Postoperative or Salvage Proton Radiotherapy for Prostate Cancer After Radical Prostatectomy.","authors":"Shivam M Kharod,&nbsp;Catherine E Mercado,&nbsp;Christopher G Morris,&nbsp;Curtis M Bryant,&nbsp;Nancy P Mendenhall,&nbsp;William M Mendenhall,&nbsp;R Charles Nichols,&nbsp;Bradford S Hoppe,&nbsp;Xiaoying Liang,&nbsp;Zhong Su,&nbsp;Zuofeng Li,&nbsp;Randal H Henderson","doi":"10.14338/IJPT-20-00021.1","DOIUrl":"https://doi.org/10.14338/IJPT-20-00021.1","url":null,"abstract":"<p><strong>Purpose: </strong>Postprostatectomy radiation improves disease control, but limited data exist regarding outcomes, toxicities, and patient-reported quality of life with proton therapy.</p><p><strong>Method and materials: </strong>The first 102 patients who were enrolled on an outcome tracking protocol between 2006 and 2017 and treated with double-scattered proton therapy after prostatectomy were retrospectively reviewed. Eleven (11%) received adjuvant radiation, while 91 (89%) received salvage radiation. Seventy-four received double-scattered proton therapy to the prostate bed only. Twenty-eight received a double-scattered proton therapy prostate-bed boost after prostate-bed and pelvic-node treatment. Eleven adjuvant patients received a median dose of 66.6 GyRBE (range, 66.0-70.2). Ninety-one salvage patients received a median dose of 70.2 GyRBE (range, 66.0-78.0). Forty-five patients received androgen deprivation therapy for a median 9 months (range, 1-30). Toxicities were scored using Common Terminology Criteria for Adverse Events v4.0 criteria, and patient-reported quality-of-life data were reviewed.</p><p><strong>Results: </strong>The median follow-up was 5.5 years (range, 0.8-11.4 years). Five-year biochemical relapse-free and distant metastases-free survival rates were 72% and 91% for adjuvant patients, 57% and 97% for salvage patients, and 57% and 97% overall. Acute and late grade 3 or higher genitourinary toxicity rates were 1% and 7%. No patients had grade 3 or higher gastrointestinal toxicity. Acute and late grade 2 gastrointestinal toxicities were 5% and 2%. The mean values and SDs of the International Prostate Symptom Score, International Index of Erectile Function, and Expanded Prostate Cancer Index Composite bowel function and bother were 7.5 (SD = 5.9), 10.2 (SD = 8.3), 92.8 (SD = 11.1), and 91.2 (SD = 6.4), respectively, at baseline, and 12.1 (SD = 9.1), 10.1 (SD = 6.7), 87.3 (SD = 18), and 86.7 (SD = 13.8) at the 5-year follow-up.</p><p><strong>Conclusion: </strong>High-dose postprostatectomy proton therapy provides effective long-term biochemical control and freedom from metastasis, with low acute and long-term gastrointestinal and genitourinary toxicity.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"7 4","pages":"52-64"},"PeriodicalIF":1.7,"publicationDate":"2021-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8019576/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25570044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}