Estimated Risk of Radiation-Induced Cancer after Thymoma Treatments with Proton- or X-ray Beams

We compared the calculated risks of radiation-induced secondary malignant neoplasms (SMNs) for patients treated for thymic tumors with 3D-CRT, IMRT, or single-field uniform dose (SFUD) proton beam therapy (PBT) using the pencil beam scanning (PBS) technique. A cancer-induction model based on the organ equivalent dose (OED) concept was used. For twelve patients, treated with 3D-CRT for thymic tumors, alternative IMRT and SFUD plans were retrospectively prepared. The resulting DVHs for organs at risk (OARs) were extracted and used to estimate the risk of SMNs. The OED was calculated using a mechanistic model for carcinoma induction. Two limit cases were considered; the linear-exponential model, in which the repopulation/repair of the cells is neglected, and the plateau model, in which full repopulation/repair of the irradiated cells is assumed. The calculated risks for SMNs for the different radiation modalities and dose-relation models were used to calculate relative risks, which were compared pairwise. The risks for developing SMNs were reduced for all OARs, and for both dose-relation models, if SFUD was used, compared to 3D-CRT and IMRT. In conclusion, PBS shows a potential benefit to reduce the risk of SMNs compared to 3D-CRT and IMRT in the treatment of thymic tumors.

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455 Proton Beam Therapy in Rectal Cancer: A Systematic Review and Meta-Analysis

British Journal of Surgery ◽

10.1093/bjs/znab135.020 ◽

2021 ◽

Vol 108 (Supplement_2) ◽

Author(s):

M Fok ◽

S Toh ◽

J E Maducolil ◽

H Fowler ◽

R Clifford ◽

...

Keyword(s):

Rectal Cancer ◽

Proton Beam ◽

Organs At Risk ◽

Meta Analysis ◽

Locally Advanced ◽

Significant Risk ◽

Proton Beam Therapy ◽

Recurrent Rectal Cancer ◽

Pelvic Bone ◽

Dosimetric Data

Abstract Introduction Radiotherapy for locally advanced rectal cancer is conventionally performed using photon-based radiotherapy (PBR), carrying significant risk of toxicity to organs at risk (OAR). Proton beam therapy (PBT) potentially delivers equivalent dosimetric radiation to the targeted tissue with improved sparing of OAR. We aimed to compare dosimetric irradiation of OAR for PBT versus PBR in patients with rectal cancer and assess any oncological outcomes. Method An extensive electronic literature search was performed from inception till April 2020 and subsequent meta-analysis performed. Results Six articles met the inclusion criteria. Dosimetric data of irradiation delivered to OAR for PBT and PBR were calculated for the same patients. PBT had significantly less irradiated small bowel compared to 3DCRT and IMRT, (MD -16.95, 95% CI [-24.03, -9.88], p < 0.00001) and (MD -6.96, 95% CI [-12.99, -0.94], p = 0.02) respectively. Similar results were observed for bladder and pelvic bone marrow. Two studies reported clinical and oncological results for PBT in recurrent rectal cancer with overall survival reported as 43% and 68%. Conclusions Dosimetric treatment plans have less irradiation of OAR for rectal cancer with PBT compared to PBR. There is a need for further research in PBT and rectal cancer, as promising results have been shown in recurrent rectal cancer.

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Dosimetric comparison between 3D conformal and intensity-modulated radiation therapy for prostate cancer

Journal of Radiotherapy in Practice ◽

10.1017/s1460396909990343 ◽

2010 ◽

Vol 9 (2) ◽

pp. 77-85 ◽

Cited By ~ 2

Author(s):

Courtney Buckey ◽

Gregory Swanson ◽

Sotirios Stathakis ◽

Nikos Papanikolaou

Keyword(s):

Radiation Therapy ◽

Organs At Risk ◽

External Beam Radiotherapy ◽

Radiation Therapy Oncology Group ◽

Intensity Modulated Radiation Therapy ◽

Standard Of Care ◽

Target Volume ◽

Conformal Radiation Therapy ◽

Intensity Modulated ◽

3D Crt

AbstractBackground and Purpose: Intensity-modulated radiation therapy (IMRT) is considered by many to be the standard of care in the delivery of external-beam radiotherapy treatments to the prostate. The purpose of this study is to assess the validity of the purported benefits of IMRT.Materials and Methods: Treatment plans were produced for 10 patients using both 3D conformal radiation therapy (3D-CRT) and IMRT, utilising the dose constraints recommended by the Radiation Therapy Oncology Group (RTOG) 0415 protocol. Three IMRT modalities used in this study were linear accelerator based IMRT, helical tomotherapy, and serial tomotherapy. The prescription to the target, 76 Gy, was the same for all plans.Results: In general the 3D-CRT plans satisfied the RTOG criteria for planning target volume (PTV) coverage, and met or bettered the dose criteria for the organs at risk. PTV coverage was more homogeneous for the IMRT plans than the 3D-CRT plans but not significantly improved.Conclusions: Technically, because the IMRT plans required greater effort for the optimisation, longer treatment times and higher monitor units, the use of IMRT for the fulfilment of the protocol’s dosimetric goals was not justified using these constraints.

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Significant Reduction of Radiation-Induced Xerostomia in Head and Neck Cancer With Intensity Modulated Radiotherapy (IMRT) Compared to Conventional 3D-Conformal Radiotherapy (3D-CRT)

International Journal of Radiation Oncology*Biology*Physics ◽

10.1016/j.ijrobp.2007.07.1544 ◽

2007 ◽

Vol 69 (3) ◽

pp. S409

Author(s):

M.R. Vergeer ◽

P. Doornaert ◽

D.H.F. Rietveld ◽

A. Jellema ◽

C.R. Leemans ◽

...

Keyword(s):

Head And Neck Cancer ◽

Head And Neck ◽

Neck Cancer ◽

Intensity Modulated Radiotherapy ◽

Conformal Radiotherapy ◽

Intensity Modulated ◽

3D Conformal Radiotherapy ◽

Radiation Induced ◽

3D Crt

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Range optimization for target and organs at risk in dynamic adaptive passive scattering proton beam therapy – A proof of concept

Physica Medica ◽

10.1016/j.ejmp.2018.11.010 ◽

2018 ◽

Vol 56 ◽

pp. 66-73

Author(s):

Shunsuke Moriya ◽

Hidenobu Tachibana ◽

Kenji Hotta ◽

Naoki Nakamura ◽

Takeji Sakae ◽

...

Keyword(s):

At Risk ◽

Proton Beam ◽

Organs At Risk ◽

Proton Beam Therapy ◽

Proof Of Concept ◽

Passive Scattering

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Transition from conformal to advanced radiotherapy techniques in treatment planning of gynecological cancer patients

Vojnosanitetski pregled ◽

10.2298/vsp210520077p ◽

2021 ◽

pp. 77-77

Author(s):

Borislava Petrovic ◽

Olivera Ivanov ◽

Milana Marjanovic ◽

Jelena Licina ◽

Ivan Gencel ◽

...

Keyword(s):

At Risk ◽

Cancer Patients ◽

Maximum Dose ◽

Organs At Risk ◽

Gynecological Cancer ◽

Conformal Radiation Therapy ◽

Significant Difference ◽

Treatment Plans ◽

Radiation Induced ◽

Risk Treatment

Background/ Aim. Transition from standard to highly conformal radiation therapy techniques, requires implementation of complex advanced dosimetry. The aim of the work was comparison of dosimetric parameters of 3DCRT and VMAT plan, as well as complications after treatment in relation to dosimetric parameters at gynecological cancer patients. Methods. Forty-nine gynecological cancer patients were included in the study. All patients were planned for 3D CRT, but due to unacceptable doses to organs at risk, treatment plans for IMRT or VMAT were generated for 21 patients. The patients were prescribed 50.4 Gy/28 fractions (4) and 45 Gy/25 fractions (45 patients). The coverage of PTV and doses to organs at risk were recorded. PTV margins were evaluated for both techniques according to the Van Herk formula. Results. ICRU 83 criteria were fulfilled in all 3DCRT /VMAT/IMRT plans providing optimal coverage of PTV. Doses to OARS: in average, the V45Gy in small bowel in IMRT/VMAT plans was four times smaller than the same of 3DCRT plans. The V45Gy of small bowels was in average 49.4cm3 in IMRT/VMAT plans, while in 3DCRT plans it was 211.6 cm3. In case of femoral head, significant reduction in V30Gy (10.8 % vs. 33.1%) and mean dose in case of IMRT/VMAT plans was recorded (30.4 Gy in 3DCRT vs 23.6 Gy). Rectum was planned with significantly lower dose in terms of V30Gy (79.5% vs 95.2%) in IMRT/VMAT plans. Bladder was better spared in VMAT plans in terms of V40Gy (51% vs. 91%), but maximum dose was higher in VMAT plans than in 3DCRT (50.1 Gy to 48.1 Gy in average). For all OARs there is statistically significant difference registered at p>0.05. Toxicities recorded in VMAT and 3DCRT patients include mainly radiation induced cystitis and enteritis. Patients treated with 3DCRT generally have longer recovery time. Homogeneity index was 0.11 for VMAT plans and 0.09 for 3DCRT plans. Conclusions. Analysis of dosimetric parameters revealed significant differences in normal tissue doses for same 3DCRT and VMAT patient, which confirmed necessity for implementation of advanced techniques for as many patients as possible.

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Identifying organs at risk for radiation-induced late dysphagia in head and neck cancer patients

Clinical and Translational Radiation Oncology ◽

10.1016/j.ctro.2019.08.005 ◽

2019 ◽

Vol 19 ◽

pp. 87-95

Author(s):

Johanna Hedström ◽

Lisa Tuomi ◽

Caterina Finizia ◽

Caroline Olsson

Keyword(s):

At Risk ◽

Head And Neck Cancer ◽

Head And Neck ◽

Cancer Patients ◽

Neck Cancer ◽

Organs At Risk ◽

Radiation Induced

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Proton beam therapy for malignant transformation of intracranial epidermoid cyst

BMJ Case Reports ◽

10.1136/bcr-2019-229388 ◽

2019 ◽

Vol 12 (7) ◽

pp. e229388

Author(s):

Zhe Chen ◽

Masayuki Araya ◽

Hiroshi Onishi

Keyword(s):

Proton Beam ◽

Malignant Transformation ◽

Epidermoid Cyst ◽

Clinical Case ◽

Proton Beam Therapy ◽

Facial Paresis ◽

Surgical Interventions ◽

Radiation Induced ◽

Intracranial Epidermoid

We report the first clinical case on the successful use of proton beam therapy in the management of malignant transformation of intracranial epidermoid cyst. A 43-year-old man was initially diagnosed as this disease with left facial paresis, hypesthesia and hypoalgesia in the territories of the trigeminal nerve. After failure of surgical interventions, he was referred to our radiation centre. We performed a postoperative proton beam therapy for treatment. We delivered a total dose of 57 GyE in 31 fractions. He tolerated the treatment well with mild acute toxicities and remained healthy and functional by 2-year follow-up postradiotherapy. No evidence of delayed radiation-induced neurotoxicity was observed.

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