1.5 T MR-linac planning study to compare two different strategies of rectal boost irradiation
Purpose: To compare treatment plans of two different rectal boost strategies: up-front versus adaptive boost at the 1.5 T MR-Linac. Methods: Patients with locally advanced rectal cancer (LARC) underwent standard neoadjuvant radiochemotherapy with 50.4 Gy in 28 fractions. T2-weighted MRI prior and af...
| Main Authors: | , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2021-01-01
|
| Series: | Clinical and Translational Radiation Oncology |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2405630820301038 |
| _version_ | 1819070367628525568 |
|---|---|
| author | Pierluigi Bonomo Monica Lo Russo Marcel Nachbar Simon Boeke Sergios Gatidis Daniel Zips Daniela Thorwarth Cihan Gani |
| author_facet | Pierluigi Bonomo Monica Lo Russo Marcel Nachbar Simon Boeke Sergios Gatidis Daniel Zips Daniela Thorwarth Cihan Gani |
| author_sort | Pierluigi Bonomo |
| collection | DOAJ |
| description | Purpose: To compare treatment plans of two different rectal boost strategies: up-front versus adaptive boost at the 1.5 T MR-Linac. Methods: Patients with locally advanced rectal cancer (LARC) underwent standard neoadjuvant radiochemotherapy with 50.4 Gy in 28 fractions. T2-weighted MRI prior and after the treatment session were acquired to contour gross tumor volumes (GTVs) and organs at risk (OARs). The datasets were used to simulate four different boost strategies (all with 15 Gy/5 fractions in addition to 50.4 Gy): up-front boost (5 daily fractions in the first week of treatment) and an adaptive boost (one boost fraction per week). Both strategies were planned using standard and reduced PTV margins. Intra-fraction motion was assessed by pre- and post-treatment MRI-based contours. Results: Five patients were included and a total of 44 MRI sets were evaluated. The median PTV volumes of the adaptive boost were significantly smaller than for the up-front boost (81.4 cm3 vs 44.4 cm3 for PTV with standard margins; 31.2 cm3 vs 15 cm3 for PTV with reduced margins; p = 0.031). With reduced margins the rectum was significantly better spared with an adaptive boost rather than with an up-front boost: V60Gy and V65Gy were 41.2% and 24.8% compared with 59% and 29.9%, respectively (p = 0.031). Median GTV intra-fractional motion was 2 mm (range 0–8 mm). Conclusions: The data suggest that the adaptive boost strategy exploiting tumor-shrinkage and reduced margin might result in better sparing of rectum and anal canal. Individual margin assessment, motion management and real-time adaptive radiotherapy appear attractive applications of the 1.5 T MR-Linac for further testing of individualized and safe dose escalation in patients with rectal cancer. |
| first_indexed | 2024-12-21T17:04:49Z |
| format | Article |
| id | doaj.art-2b78b605ec6a42adb08a8e184586d8bb |
| institution | Directory Open Access Journal |
| issn | 2405-6308 |
| language | English |
| last_indexed | 2024-12-21T17:04:49Z |
| publishDate | 2021-01-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Clinical and Translational Radiation Oncology |
| spelling | doaj.art-2b78b605ec6a42adb08a8e184586d8bb2022-12-21T18:56:33ZengElsevierClinical and Translational Radiation Oncology2405-63082021-01-012686911.5 T MR-linac planning study to compare two different strategies of rectal boost irradiationPierluigi Bonomo0Monica Lo Russo1Marcel Nachbar2Simon Boeke3Sergios Gatidis4Daniel Zips5Daniela Thorwarth6Cihan Gani7Department of Radiation Oncology, Azienda Ospedaliero-Universitaria Careggi, University of Florence, Florence, ItalyDepartment of Radiation Oncology, University Hospital and Medical Faculty, Eberhard Karls University, Tübingen, Germany; Corresponding author.Section for Biomedical Physics, Department of Radiation Oncology, University Hospital Tübingen, 72076 Tübingen, GermanyDepartment of Radiation Oncology, University Hospital and Medical Faculty, Eberhard Karls University, Tübingen, GermanyDepartment of Diagnostic and Interventional Radiology, University-Hospital Tübingen, GermanyDepartment of Radiation Oncology, University Hospital and Medical Faculty, Eberhard Karls University, Tübingen, Germany; German Cancer Research Center (DKFZ) Heidelberg and German Consortium for Translational Cancer Research (DKTK), Partner Site Tübingen, Tübingen, GermanySection for Biomedical Physics, Department of Radiation Oncology, University Hospital Tübingen, 72076 Tübingen, Germany; German Cancer Research Center (DKFZ) Heidelberg and German Consortium for Translational Cancer Research (DKTK), Partner Site Tübingen, Tübingen, GermanyDepartment of Radiation Oncology, University Hospital and Medical Faculty, Eberhard Karls University, Tübingen, Germany; German Cancer Research Center (DKFZ) Heidelberg and German Consortium for Translational Cancer Research (DKTK), Partner Site Tübingen, Tübingen, GermanyPurpose: To compare treatment plans of two different rectal boost strategies: up-front versus adaptive boost at the 1.5 T MR-Linac. Methods: Patients with locally advanced rectal cancer (LARC) underwent standard neoadjuvant radiochemotherapy with 50.4 Gy in 28 fractions. T2-weighted MRI prior and after the treatment session were acquired to contour gross tumor volumes (GTVs) and organs at risk (OARs). The datasets were used to simulate four different boost strategies (all with 15 Gy/5 fractions in addition to 50.4 Gy): up-front boost (5 daily fractions in the first week of treatment) and an adaptive boost (one boost fraction per week). Both strategies were planned using standard and reduced PTV margins. Intra-fraction motion was assessed by pre- and post-treatment MRI-based contours. Results: Five patients were included and a total of 44 MRI sets were evaluated. The median PTV volumes of the adaptive boost were significantly smaller than for the up-front boost (81.4 cm3 vs 44.4 cm3 for PTV with standard margins; 31.2 cm3 vs 15 cm3 for PTV with reduced margins; p = 0.031). With reduced margins the rectum was significantly better spared with an adaptive boost rather than with an up-front boost: V60Gy and V65Gy were 41.2% and 24.8% compared with 59% and 29.9%, respectively (p = 0.031). Median GTV intra-fractional motion was 2 mm (range 0–8 mm). Conclusions: The data suggest that the adaptive boost strategy exploiting tumor-shrinkage and reduced margin might result in better sparing of rectum and anal canal. Individual margin assessment, motion management and real-time adaptive radiotherapy appear attractive applications of the 1.5 T MR-Linac for further testing of individualized and safe dose escalation in patients with rectal cancer.http://www.sciencedirect.com/science/article/pii/S2405630820301038MR-guided radiotherapyRectal cancerMR-linacBoostAdaptive radiotherapy |
| spellingShingle | Pierluigi Bonomo Monica Lo Russo Marcel Nachbar Simon Boeke Sergios Gatidis Daniel Zips Daniela Thorwarth Cihan Gani 1.5 T MR-linac planning study to compare two different strategies of rectal boost irradiation Clinical and Translational Radiation Oncology MR-guided radiotherapy Rectal cancer MR-linac Boost Adaptive radiotherapy |
| title | 1.5 T MR-linac planning study to compare two different strategies of rectal boost irradiation |
| title_full | 1.5 T MR-linac planning study to compare two different strategies of rectal boost irradiation |
| title_fullStr | 1.5 T MR-linac planning study to compare two different strategies of rectal boost irradiation |
| title_full_unstemmed | 1.5 T MR-linac planning study to compare two different strategies of rectal boost irradiation |
| title_short | 1.5 T MR-linac planning study to compare two different strategies of rectal boost irradiation |
| title_sort | 1 5 t mr linac planning study to compare two different strategies of rectal boost irradiation |
| topic | MR-guided radiotherapy Rectal cancer MR-linac Boost Adaptive radiotherapy |
| url | http://www.sciencedirect.com/science/article/pii/S2405630820301038 |
| work_keys_str_mv | AT pierluigibonomo 15tmrlinacplanningstudytocomparetwodifferentstrategiesofrectalboostirradiation AT monicalorusso 15tmrlinacplanningstudytocomparetwodifferentstrategiesofrectalboostirradiation AT marcelnachbar 15tmrlinacplanningstudytocomparetwodifferentstrategiesofrectalboostirradiation AT simonboeke 15tmrlinacplanningstudytocomparetwodifferentstrategiesofrectalboostirradiation AT sergiosgatidis 15tmrlinacplanningstudytocomparetwodifferentstrategiesofrectalboostirradiation AT danielzips 15tmrlinacplanningstudytocomparetwodifferentstrategiesofrectalboostirradiation AT danielathorwarth 15tmrlinacplanningstudytocomparetwodifferentstrategiesofrectalboostirradiation AT cihangani 15tmrlinacplanningstudytocomparetwodifferentstrategiesofrectalboostirradiation |