Abstract
PurposeTo search for abscopal effects (AE) distant to the site of radiation after sequential Yittrium-90 (Y-90) radioembolization (RE) of liver malignancies.Methods and MaterialsIn this retrospective analysis, all patients treated by RE between 2007 and 2018 (n = 907) were screened for the following setting/conditions: sequential RE of left and right liver lobe in two sessions, liver-specific MRI (MRI1) acquired max. 10 days before or after first RE (RE1), liver-specific MRI (MRI2) acquired with a minimum time interval of 20 days after MRI1, but before second RE (RE2). No systemic tumor therapies between MRI1 and MRI2. No patients with liver cirrhosis. Metastases > 5 mm in untreated liver lobes were compared in MRI1 and MRI2 and rated as follows: same size or larger in MRI2 = no abscopal effect (NAE); > 30% shrinkage without Y-90 contamination in SPECT/CT = abscopal effect (AE).ResultsNinety six of 907 patients met aforementioned criteria. Median time-frame between RE1 and MRI2 was 34 (20–64) days. These 96 cases had 765 metastases which were evaluable (median 5(1–40) metastases per patient). Four patients could be identified with at least one shrinking metastasis of the untreated site: one patient with breast cancer (3 metastases: 0 NAE; 3 AE), one patient with prostate cancer (6 metastases: 3 NAE; 3 metastases > 30% shrinkage but possible Y-90 contamination) and two patients with shrinkage of one metastasis each but less than 30%.ConclusionOur retrospective study documents AE after RE of liver tumors in 1 out of 96 cases, 3 other cases remain unclear.
Highlights
Radiotherapy (RT) represents one cornerstone of the established oncological treatment regimens
In this retrospective analysis, all patients treated by RE between 2007 and 2018 (n = 907) were screened for the following setting/conditions: sequential RE of left and right liver lobe in two sessions, liver-specific MRI (MRI1) acquired max. 10 days before or after first RE (RE1), liver-specific MRI (MRI2) acquired with a minimum time interval of 20 days after MRI1, but before second RE (RE2)
The analysis revealed two patients whose untreated metastases demonstrated noticeable shrinkage but \ 20% in diameter (Fig. 4)
Summary
Radiotherapy (RT) represents one cornerstone of the established oncological treatment regimens. Phenomenon of tumor regression at distant sites following RT, suggesting that radiation therapy has a far-reaching or delayed influence on non-irradiated cells, i.e., the abscopal effect (AE). The mode of tumor cell death through radiation is a crucial factor for immune activation—diverse phenotypes of apoptosis, necrosis, mitotic catastrophe and senescence can be observed and are reviewed elsewhere [2]. Immunogenic forms of cell deaths can convert the tumor or metastasis into an in situ vaccine by releasing damage-associated molecular patterns (DAMPs) [3,4,5] unleashing a cascade of recruitment, differentiation and activation of antigen-presenting cells (APC), which are responsible for priming of an anti-tumor immunity [6, 7]. The clinical changes, which arise distant from the irradiated site are deemed to be the result of various factors released by the cancer cells as well as the corresponding immune cells [8]. Several immunomodulatory substances are available to overcome immune inhibition, especially immune check-point-inhibitors have shown remarkable efficacy boosting the abscopal effects in both clinical and preclinical situations [9,10,11]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
