Safety margin in irradiation of colorectal liver metastases: assessment of the control dose of micrometastases
<p>Abstract</p> <p>Backround</p> <p>Micrometastases of colorectal liver metastases are present in up to 50% of lesions. In this study we sought to determine the threshold dose for local control of occult micrometastases in patients undergoing CT (computed tomography)-gu...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
BMC
2010-03-01
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| Series: | Radiation Oncology |
| Online Access: | http://www.ro-journal.com/content/5/1/24 |
| _version_ | 1811246818639478784 |
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| author | Seidensticker Max Wust Peter Rühl Ricarda Mohnike Konrad Pech Maciej Wieners Gero Gademann Günther Ricke Jens |
| author_facet | Seidensticker Max Wust Peter Rühl Ricarda Mohnike Konrad Pech Maciej Wieners Gero Gademann Günther Ricke Jens |
| author_sort | Seidensticker Max |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Backround</p> <p>Micrometastases of colorectal liver metastases are present in up to 50% of lesions. In this study we sought to determine the threshold dose for local control of occult micrometastases in patients undergoing CT (computed tomography)-guided brachytherapy of colorectal liver metastases.</p> <p>Materials and methods</p> <p>Nineteen patients demonstrated 34 local tumor recurrences originating from micrometastases after CT-guided brachytherapy of 27 colorectal liver metastases. We considered a local tumor recurrence as originating from a micrometastasis if tumor regrowth occurred adjacent to a formerly irradiated lesion and the distance of the 3D isocenter of the new lesion was ≤ 23.5 mm from the previous tumor margin. Follow-up MRI was fused with the planning-CT and dosimetry data. Two reviewers independently indicated the dose exposure at the isocenter of the micrometastases. Statistical analysis included an analysis of variance (ANOVA) using backward selection. 95% tolerance intervals with coverage of 87.5 and 75% of the data of the normal distribution were calculated.</p> <p>Results</p> <p>The median distance of the micrometastases to the margin of the originating colorectal metastases was 8.75 mm (1-21 mm). Dose exposure at the isocenter was 12.25 Gy (7-19.8) in median. We stratified according to the distance from the isocenter to the initial tumor margin: ≤ 9 mm, > 9-15 mm and > 15 mm. The median dose in the according isocenters was 13.18, 11.6 and 11.85 Gy. The threshold dose failing to prevent micrometastasis growth was sigificantly higher in a subgroup of lesions with ≤ 9 mm distance as compared to > 15 mm (13.18 vs 11.85 Gy). Adjuvant chemotherapy correlated with greater distance of micrometastasis growth to the tumor but not with the threshold dose.</p> <p>Conclusion</p> <p>To prevent loss of local tumor control by continuous growth of micrometastases a threshold dose of 15,4 Gy (single fraction) should be delivered at a distance of 21 mm to the gross tumor margin.</p> |
| first_indexed | 2024-04-12T15:00:11Z |
| format | Article |
| id | doaj.art-68ca7013694b4d7ebfdf3d8d25af9f83 |
| institution | Directory Open Access Journal |
| issn | 1748-717X |
| language | English |
| last_indexed | 2024-04-12T15:00:11Z |
| publishDate | 2010-03-01 |
| publisher | BMC |
| record_format | Article |
| series | Radiation Oncology |
| spelling | doaj.art-68ca7013694b4d7ebfdf3d8d25af9f832022-12-22T03:28:07ZengBMCRadiation Oncology1748-717X2010-03-01512410.1186/1748-717X-5-24Safety margin in irradiation of colorectal liver metastases: assessment of the control dose of micrometastasesSeidensticker MaxWust PeterRühl RicardaMohnike KonradPech MaciejWieners GeroGademann GüntherRicke Jens<p>Abstract</p> <p>Backround</p> <p>Micrometastases of colorectal liver metastases are present in up to 50% of lesions. In this study we sought to determine the threshold dose for local control of occult micrometastases in patients undergoing CT (computed tomography)-guided brachytherapy of colorectal liver metastases.</p> <p>Materials and methods</p> <p>Nineteen patients demonstrated 34 local tumor recurrences originating from micrometastases after CT-guided brachytherapy of 27 colorectal liver metastases. We considered a local tumor recurrence as originating from a micrometastasis if tumor regrowth occurred adjacent to a formerly irradiated lesion and the distance of the 3D isocenter of the new lesion was ≤ 23.5 mm from the previous tumor margin. Follow-up MRI was fused with the planning-CT and dosimetry data. Two reviewers independently indicated the dose exposure at the isocenter of the micrometastases. Statistical analysis included an analysis of variance (ANOVA) using backward selection. 95% tolerance intervals with coverage of 87.5 and 75% of the data of the normal distribution were calculated.</p> <p>Results</p> <p>The median distance of the micrometastases to the margin of the originating colorectal metastases was 8.75 mm (1-21 mm). Dose exposure at the isocenter was 12.25 Gy (7-19.8) in median. We stratified according to the distance from the isocenter to the initial tumor margin: ≤ 9 mm, > 9-15 mm and > 15 mm. The median dose in the according isocenters was 13.18, 11.6 and 11.85 Gy. The threshold dose failing to prevent micrometastasis growth was sigificantly higher in a subgroup of lesions with ≤ 9 mm distance as compared to > 15 mm (13.18 vs 11.85 Gy). Adjuvant chemotherapy correlated with greater distance of micrometastasis growth to the tumor but not with the threshold dose.</p> <p>Conclusion</p> <p>To prevent loss of local tumor control by continuous growth of micrometastases a threshold dose of 15,4 Gy (single fraction) should be delivered at a distance of 21 mm to the gross tumor margin.</p>http://www.ro-journal.com/content/5/1/24 |
| spellingShingle | Seidensticker Max Wust Peter Rühl Ricarda Mohnike Konrad Pech Maciej Wieners Gero Gademann Günther Ricke Jens Safety margin in irradiation of colorectal liver metastases: assessment of the control dose of micrometastases Radiation Oncology |
| title | Safety margin in irradiation of colorectal liver metastases: assessment of the control dose of micrometastases |
| title_full | Safety margin in irradiation of colorectal liver metastases: assessment of the control dose of micrometastases |
| title_fullStr | Safety margin in irradiation of colorectal liver metastases: assessment of the control dose of micrometastases |
| title_full_unstemmed | Safety margin in irradiation of colorectal liver metastases: assessment of the control dose of micrometastases |
| title_short | Safety margin in irradiation of colorectal liver metastases: assessment of the control dose of micrometastases |
| title_sort | safety margin in irradiation of colorectal liver metastases assessment of the control dose of micrometastases |
| url | http://www.ro-journal.com/content/5/1/24 |
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