Long-term characterization of MRI-morphologic alterations after active motion-compensated liver SBRT: a multi-institutional pooled analysis

Constantin Dreher; Gustavo R Sarria; Georgia Miebach; Christel Weiss; Daniel Buergy; Paulina Wojtal; Anoshirwan A Tavakoli; David Krug; Hans Oppitz; Frank A Giordano; Marcus Both; Frank Lohr; Jürgen Dunst; Oliver Blanck; Judit Boda-Heggemann

doi:10.1080/0284186X.2023.2187707

Long-term characterization of MRI-morphologic alterations after active motion-compensated liver SBRT: a multi-institutional pooled analysis

Acta Oncol. 2023 Mar;62(3):281-289. doi: 10.1080/0284186X.2023.2187707. Epub 2023 Apr 5.

Authors

Constantin Dreher^{1

2}, Gustavo R Sarria³, Georgia Miebach¹, Christel Weiss⁴, Daniel Buergy^{1

2}, Paulina Wojtal¹, Anoshirwan A Tavakoli⁵, David Krug^{6

7}, Hans Oppitz¹, Frank A Giordano^{1

2}, Marcus Both⁸, Frank Lohr⁹, Jürgen Dunst⁶, Oliver Blanck^{6

7}, Judit Boda-Heggemann^{1

2}

Affiliations

¹ Department of Radiation Oncology, University Medical Center Mannheim, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany.
² DKFZ-Hector Cancer Institute, University Medical Center Mannheim, Mannheim, Germany.
³ Department of Radiation Oncology, University Hospital Bonn, University of Bonn, Bonn, Germany.
⁴ Department of Medical Statistics and Biomathematics, University Medical Center Mannheim, University of Heidelberg, Mannheim, Germany.
⁵ Department of Radiology, University Medical Center Mannheim, University of Heidelberg, Mannheim, Germany.
⁶ Department of Radiation Oncology, University Medical Center Schleswig-Holstein, Kiel, Germany.
⁷ Saphir Radiosurgery Center Northern Germany, Kiel, Germany.
⁸ Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein, Kiel, Germany.
⁹ Dipartimento di Oncologia, UO di Radioterapia, Azienda Ospedaliero-Universitaria di Modena, Modena, Italy.

PMID: 37017543
DOI: 10.1080/0284186X.2023.2187707

Abstract

Background: Stereotactic body radiotherapy (SBRT) is an effective therapeutic approach in patients with liver metastases. However, long-term changes in hepatic normal tissue have to be taken into account in multimodal treatment regimes. Magnetic-resonance-imaging (MRI) based morphologic liver alterations (MMA) after liver SBRT have been analyzed longitudinally.

Material and methods: 57 patients treated with gantry-based or robotic-based SBRT of 69 treatment volumes of liver metastases, who had long-term follow-up (FU) ≥6 months were included in this retrospective analysis. Post-SBRT MMAs were contoured on each contrast-enhanced-T1-weighted (T1w) MRI-sequence. Morphologic/volumetric data of the liver and MMAs were evaluated longitudinally, including the dependency on treatment-related factors of the planning target volume (PTV) and liver.

Results: The median FU time was 1 year [6-48 months]. 66 of 69 treatment volumes developed MMAs (mean 143.8 ± 135.1 ccm at first appearance). 31.8% of MMAs resolved completely during FU. Of the persisting MMAs 82.2%/13.3% decreased/increased in size until last available FU. Morphological characterization of the MMAs at first appearance included 75% hypointense and 25% hyperintense T1w-MRI-based appearances. Hypointense as compared to hyperintense appearance was significantly associated with a higher mean liver dose EQD2_{α/β=3 Gy} (p = 0.0212) and non-significantly greater MMA size. Variance analysis demonstrated a significant reduction of MMA and total liver volume after SBRT (p < 0.0001). The volume reduction decelerated longitudinally for both MMA (p < 0.0001) and liver size (p = 0.0033). Radiation doses (PTV-BED_{α/β=3 Gy and 10 Gy}) were not significantly associated with MMA volume reduction. SBRT of liver metastases with mean liver dose EQD2_{α/β=3 Gy} > 18 Gy were characterized by greater MMA volumes (p = 0.0826) and steeper MMA reduction gradients during FU than those with EQD2_{α/β=3 Gy} ≤ 18 Gy (p < 0.0001).

Conclusion: Radiogenic MMAs either completely resolve or usually decrease in volume with pronounced reduction during short-term FU. This course was independent of the MMA's morphological appearance. Further, increased mean liver dose was associated with greater MMA size and a greater gradient of MMA size reduction during FU.

Keywords: MRI; SBRT; healthy tissue response; liver; metastases.

Publication types

Multicenter Study

MeSH terms

Humans
Liver Neoplasms* / diagnostic imaging
Liver Neoplasms* / pathology
Liver Neoplasms* / radiotherapy
Magnetic Resonance Imaging
Radiosurgery* / adverse effects
Radiosurgery* / methods
Radiotherapy Dosage
Retrospective Studies