High dose proton and photon-based radiation therapy for 213 liver lesions: a multi-institutional dosimetric comparison with a clinical perspective.

Radiol Med. 2024 Mar;129(3):497-506. doi: 10.1007/s11547-024-01788-w. Epub 2024 Feb 12.

Bonù ML(1), Nicosia L(2), Turkaj A(3), Pastorello E(4), Vitali P(4), Frassine F(4), Toraci C(5), Spiazzi L(5), Lechiara M(6), Frittoli B(6), Grazioli L(6), Ghirardelli P(7), Costantino G(7), Barbera F(4), Borghetti P(4), Triggiani L(4), Portolani N(8), Buglione M(4), Dionisi F(9), Giacomelli I(3), Lancia A(10), Magrini SM(4), Tomasini D(4).

Author information:

(1)Department of Radiation Oncology, Istituto del Radio O. Alberti, University of Brescia and Spedali Civili Hospital, Piazzale Spedali Civili 1, 25121, Brescia, Italy. marco.bonu@unibs.it. (2)Department of Radiation Oncology, Ospedale Sacro Cuore Don Calabria, Negrar, Italy. (3)Proton Therapy Center, Trento, Italy. (4)Department of Radiation Oncology, Istituto del Radio O. Alberti, University of Brescia and Spedali Civili Hospital, Piazzale Spedali Civili 1, 25121, Brescia, Italy. (5)Department of Medical Physics, Spedali Civili di Brescia, Brescia, Italy. (6)Department of Radiology, Spedali Civili di Brescia, Brescia, Italy. (7)Department of Radiation Oncology, Humanitas Gavazzeni Hospital, Bergamo, Italy. (8)Department of Surgery, Spedali Civili di Brescia, Brescia, Italy. (9)Radiation Oncology, Regina Elena Institute, IFO, Rome, Italy. (10)Department of Radiation Oncology, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy.

BACKGROUND: Stereotactic radiotherapy (SRT) and Proton therapy (PT) are both options in the management of liver lesions. Limited clinical-dosimetric comparison are available. Moreover, dose-constraint routinely used in liver PT and SRT considers only the liver spared, while optimization strategies to limit the liver damaged are poorly reported.

METHODS: Primary endpoint was to assess and compare liver sparing of four contemporary RT techniques. Secondary endpoints were freedom from local recurrence (FFLR), overall survival (OS), acute and late toxicity. We hypothesize that Focal Liver Reaction (FLR) is determined by a similar biologic dose. FLR was delineated on follow-up MRI. Mean C.I. was computed for all the schedules used. A so-called Fall-off Volume (FOV) was defined as the area of healthy liver (liver-PTV) receiving more than the isotoxic dose. Fall-off Volume Ratio (FOVR) was defined as ratio between FOV and PTV. 

RESULTS: 213 lesions were identified. Mean best fitting isodose (isotoxic doses) for FLR were 18Gy, 21.5 Gy and 28.5 Gy for 3, 5 and 15 fractions. Among photons, an advantage in terms of healthy liver sparing was found for Vmat FFF with 5mm jaws (p = 0.013) and Cyberknife (p = 0.03). FOV and FOVR resulted lower for PT (p < 0.001). Three years FFLR resulted 83%. Classic Radiation induced liver disease (RILD, any grade) affected 2 patients.

CONCLUSIONS: Cyberknife and V-MAT FFF with 5mm jaws spare more liver than V-MAT FF with 10 mm jaws. PT spare more liver compared to photons. FOV and FOVR allows a quantitative analysis of healthy tissue sparing performance showing also the quality of plan in terms of dose fall-off.

© 2024. The Author(s).

DOI: 10.1007/s11547-024-01788-w

PMCID: PMC10942931

PMID: 38345714 [Indexed for MEDLINE]

Conflict of interest statement: None.