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Background and Aim: This study aimed to investigate the association between liver volume change and hepatic decompensation and compare the risk of hepatic decompensation in patients with liver cirrhosis (LC) and hepatocellular carcinoma (HCC) who underwent stereotactic body radiation therapy (SBRT). Methods: A retrospective review of SBRT‐treated HCC and compensated LC without HCC patients was conducted. Liver volume was measured using auto‐segmentation software on liver dynamic computed tomography scans. The decompensation event was defined as the first occurrence of refractory ascites, esophageal variceal bleeding, hepatic encephalopathy, or spontaneous bacterial peritonitis. We evaluated the association between the rate of liver volume decrease and hepatic decompensation and compared decompensation events between the SBRT and LC cohorts using propensity score matching. Results: A total of 138 patients from the SBRT cohort and 488 from the LC cohort were analyzed. The rate of liver volume decrease was associated with the risk of decompensation events in both cohorts. The 3‐year rate of decompensation events was significantly higher in the group with a liver volume decreasing rate > 7%/year compared with the group with a rate < 7%/year. In the propensity score‐matched cohort, the 3‐year rate of decompensation events after a single session of SBRT was not significantly different from that in the LC cohort. Conclusions: The rate of liver volume decrease was significantly associated with the risk of hepatic decompensation in both HCC patients who received SBRT and LC patients. A single session of SBRT for HCC did not result in a higher decompensation rate compared with LC. [ABSTRACT FROM AUTHOR]

Background: To evaluate the clinical outcomes of patients who received stereotactic body radiation therapy (SBRT) for single viable hepatocellular carcinoma (HCC) at the site of incomplete transarterial chemoembolization (TACE).Methods: Patients treated with SBRT for single viable HCC after incomplete TACE between 2012 and 2017 at Asan Medical Center (Seoul, South Korea) were included. Incomplete TACE was defined as (1) evidence of viable HCC at the site of TACE on follow-up dynamic computed tomography (CT) or magnetic resonance imaging following one or more consecutive TACEs, (2) no definite tumor staining on superselective hepatic angiogram, or (3) no definite iodized oil uptake on post-embolization angiogram or CT. Doses of 10-15 Gy per fraction were given over 3-4 consecutive days. The primary outcome was local control rate at 3 years and secondary outcome included tumor response, overall survival rate, out-of-field intrahepatic recurrence-free survival, distant metastasis-free survival and treatment-related toxicities. Treatment-related adverse events were evaluated according to the common terminology criteria for adverse events, version 4.03.Results: A total of 302 patients were analyzed. The median follow-up duration was 32.9 months (interquartile range [IQR], 23.6-41.7) and the median tumor size was 2.0 cm (range, 0.7-6.9). The local control (LC) and overall survival rates at 3 years were 91.2 and 72.7%, respectively. 95.4% of the tumors reached complete response (CR) during the entire follow-up period (anyCR). The median interval from SBRT to anyCR was 3.4 months (IQR, 1.9-4.7), and 39.9 and 83.3% of the lesions reached CR at 3- and 6-months after SBRT, respectively. Radiation-induced liver disease was observed in 8 (2.6%) patients. No patients experienced gastroduodenal bleeding within the radiation field.Conclusion: SBRT could be considered a feasible salvage treatment option for HCC after incomplete TACE. [ABSTRACT FROM AUTHOR]

Background and Aim: We compared the clinical outcomes of radiofrequency ablation (RFA) and stereotactic body radiation therapy (SBRT) in small (≤ 3 cm) hepatocellular carcinoma. Methods: A total of 266 patients treated with RFA (n = 179) or SBRT (n = 87) were reviewed. Local control rates (LCRs), intrahepatic recurrence‐free survival (IHRFS) rates, and overall survival (OS) rates were compared. Inverse probability of treatment weighting (IPTW) was used to adjust for imbalances in baseline characteristics between the two groups. Results: The median follow‐up period was 50.3 months, and treatment method (RFA vs SBRT) was not a significant prognostic factor for LCR, OS, and IHRFS in both multivariate and IPTW‐adjusted analyses. The 4‐year LCRs after RFA and SBRT were 92.7% and 95.0%, respectively. Perivascular location was a significant prognostic factor for LCR in the entire patients and in the RFA group, but not in the SBRT group. The 4‐year OS rates in the RFA and SBRT groups were 78.1% and 64.1%, respectively (P = 0.012). After IPTW adjustment, the 4‐year LCRs (90.6% vs 96.3%) and OS rates (71.8% vs 70.2%) were not significantly different between the two groups. The rate of grade ≥ 3 adverse events was 0.6% (n = 1) in the RFA group and 1.1% (n = 1) in the SBRT group. Conclusions: The two treatment methods showed comparable outcomes in terms of LCR, OS rate, and IHRFS rate after IPTW adjustment. SBRT seems to be a viable alternative method for small hepatocellular carcinomas that are not suitable for RFA due to tumor location. [ABSTRACT FROM AUTHOR]

Background and Aim: The purpose of this study was to investigate the long‐term oncologic outcomes after stereotactic body radiation therapy (SBRT) for small hepatocellular carcinoma (HCC). Methods: A total of 290 patients with HCC were registered between March 2007 and July 2013. A dose of 10–15 Gy per fraction was given over three to four consecutive days, resulting in a total dose of 30–60 Gy. Overall and recurrence‐free survivals were estimated from the date of the start of SBRT to the date of death, the last follow‐up examination, or to the date of tumor recurrence. Results: The median follow‐up period of all patients was 38.2 months, and the median tumor size was 1.7 cm. Overall survival (OS) rate at 5 years was 44.9%. Multivariate analyses revealed that age, Child–Pugh class, tumor size, and albumin levels were significant factors for OS. The 5‐year local control rate was 91.3%. In multivariate analysis, tumor size and albumin were significantly associated with local tumor control. However, there was a negative correlation between total dose and tumor size in Pearson's correlation analysis (r = −0.111, P = 0.046). Conclusions: Stereotactic body radiation therapy was an excellent ablative treatment option for patients with small HCC. Tumor size was a significant factor for local tumor control after SBRT, although the total dose was negatively correlated with tumor size. Considering the low OS rates and the high local tumor control rates, the combined SBRT and systemic therapies may be beneficial for improving survival outcomes. [ABSTRACT FROM AUTHOR]

Purpose: To assess the potential dosimetric benefits associated with the CyberKnife (CK) tumor tracking capability, wherein an extra margin for respiratory tumor motion is not required, when compared to respiratory-gated volumetric-modulated arc therapy (VMAT) for hepatocellular carcinoma (HCC). Methods: Twenty-nine HCC patients previously treated with double-arc VMAT were enrolled. In each VMAT plan, the individual internal target volume (ITV) margin around the tumor was determined by measuring its motion over 30–70% of respiratory phases using four-dimensional computed tomography, followed by a 5-mm isotropic margin for the planning target volume (PTV). For each VMAT plan, two CK plans were generated using the original (CKoriginal, ITV included) and modified PTVs (CKmodified, ITV excluded) for comparison. In each case, the CKoriginal and CKmodified plans were compared to the original VMAT plan in terms of the dosimetric parameters including the conformity index (CI), PTV coverage (CO), organs at risk (OAR) doses, and normal liver tissue sparing. Results: The original PTVs with median 24 cc (range, 9–65 cc) were significantly reduced to median 12 cc (range, 5–41 cc) in the CKmodified plans. Statistically significant differences in plan qualities were observed between the VMAT and the CK plans: mean CI, 1.05 in VMAT vs. 1.17 in both CK plans (p < 0.001); and mean CO, 93.0% in VMAT vs. 96.6% in CKoriginal and 96.9% in CKmodified (p < 0.001). The average volume of normal liver tissue receiving > 15 Gy was significantly decreased in the CKmodified plan, as compared to that in the VMAT and CKoriginal plans, by 1.75- and 1.61-fold, respectively. Conclusions: The tumor tracking capability of the CK system can significantly decrease the volume of normal liver tissue receiving > 15 Gy, while maintaining high precision in target localization, conformity, tumor coverage, and dose sparing of the OAR. Therefore, it can be a valuable SBRT option, particularly for HCC patients with poor liver function. [ABSTRACT FROM AUTHOR]

Introduction: The present study evaluated the threshold dose for hepatic parenchymal changes on gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance (MR) images after stereotactic body radiation therapy (SBRT) for hepatocellular carcinoma (HCC). Methods: Twenty patients with available data of follow-up MR images acquired 2-4 months after completion of SBRT were selected among the registered patients. SBRT was performed using multiple coplanar and non-coplanar beams with energies of 6 or 15 MV. All patients were treated with doses of 45 Gy administered in three fractions over 3 consecutive days. For image registration between planning computed tomography (CT) and MR images, landmark-based rigid body registration was performed using MIM software. Results: Seventeen patients were included in the analysis. The median discrepancies between planning CT and MR images in the left-right, anterior-posterior and superior-inferior directions were 1.38 mm, 1.24 mm and 1.72 mm, respectively. The median D50 value for the defect in the hepatobiliary phase of Gd-EOB-DTPA-enhanced MR images after SBRT was 19.8 Gy (range, 14.2-28.7 Gy), with R(2) values ranging from 0.76 to 0.99. Conclusions: The threshold dose for parenchymal changes in the hepatobiliary phase of Gd-EOB-DTPA-enhanced MR images performed 2-4 months after 45 Gy of SBRT in three fractions was approximately 20 Gy. Our results provide the basis for further research on the functional loss of liver parenchyma after SBRT. [ABSTRACT FROM AUTHOR]

Background: To assess the significance of alpha-fetoprotein (AFP) normalization as a prognostic surrogate after stereotactic body radiotherapy (SBRT) for patients with small hepatocellular carcinoma (HCC).Methods: Patients who underwent SBRT for primary or recurrent HCC were registered and a database thereof was retrospectively reviewed. Among 165 total registered patients, 77 patients were selected who satisfied the following criteria: (1) their AFP levels were > 20 ng/mL before SBRT, and (2) their AFP levels were checked within three months after SBRT. Propensity score based matching analysis was performed to minimize potential confounding bias. AFP normalization was defined as a reduction of AFP level to ≤ 20 ng/mL. Overall survival (OS) and progression-free survival (PFS) curves were estimated by the Kaplan-Meier method.Results: Thirty-seven (48.1 %) patients displayed AFP normalization (normalized group), while 40 (51.9 %) patients comprised the non-normalized group. The OS rates at 3-year were 62.0 % and 44.0 % (p = 0.023), and the PFS rates at 3-year were 27.9 % and 12.0 % (p = 0.019), in the normalized and non-normalized groups, respectively. Local control rates were 97.2 % in the normalized group and 94.7 % in the non-normalized group at three years (p = 0.579). In the propensity score matching cohort (25 pairs), OS and PFS were significantly longer in the normalized group than in the non-normalized group (p = 0.017 and 0.049, respectively). The local control rates were 100 % in both matched groups.Conclusions: AFP normalization within three months after SBRT is a prognostic surrogate for OS and PFS in patients with small HCC. AFP monitoring should be considered a useful tool for HCC patients with an elevated AFP level before SBRT. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate temporal changes in contrast enhancement patterns of non-tumorous hepatic parenchyma with a focus on arterial hypervascularity on multiphase computed tomography (CT) in patients with hepatocellular carcinoma (HCC) treated with stereotactic body radiotherapy (SBRT). Methods: We retrospectively identified 61 patients who had undergone multiphase contrast-enhanced CT at one, three, and six months after SBRT. Irradiated versus non-irradiated liver parenchyma was delineated by cross-correlation with the dose-volume histogram of SBRT plan. Serial changes in the contrast enhancement patterns of the irradiated versus non-irradiated liver parenchyma were evaluated by two abdominal radiologists in consensus. We compared the frequency of the contrast enhancement patterns according to the follow-up period using the Fisher-Freeman-Halton exact test. Results: The irradiated non-tumorous hepatic parenchyma showed that the prevalence of arterial hypervascularity increased during the follow-up period (P<.01): 11.5% (7/61) in one, 45.9% (28/61) in three, and 54.1% (33/61) in six months. Contrast wash-out on the delayed phase was uncommon: 1.6% (1/61) in one, 3.3% (2/61) in three, and 0% in six months. Conclusion: The incidence of arterial hypervascularity of the irradiated hepatic parenchyma gradually increased until six months after SBRT, which could interfere with the accurate evaluation of treatment response. The lack of wash-out on the delayed phase in the hypervascular area would distinguish SBRT-related change from residual/recurred HCC. [ABSTRACT FROM AUTHOR]

Background and Aim In cases of small hepatocellular carcinoma ( HCC) where established curative treatment cannot be applied, stereotactic body radiotherapy ( SBRT) has been used as a non-invasive alternative treatment modality. However, short-course SBRT may not be safe if the tumor is located around a critical normal organ. Therefore, we applied hypofractionated radiotherapy for these tumors and evaluated outcomes of this treatment. Methods Between December 2008 and August 2011, 26 patients (28 lesions) with HCC were treated with hypofractionated radiotherapy. Inclusion criteria were HCC not suitable for surgery or other local ablative therapy, a tumor size < 6 cm, adequate hepatic function, an HCC located within 2 cm of a critical organ, and no evidence of vascular invasion. A dose of 4-5 Gy per fraction was given, with a total dose of 40-50 Gy over 2 weeks. Results The overall response rate was 67.9%, with seven complete responses (25.0%) and 12 partial responses (42.9%) at 3 months after radiotherapy. The overall survival rates at 1 and 2 years were 88.5% and 67.2%, respectively. The local control rate at 2 years was 87.6%. The Intrahepatic recurrence-free and distant failure-free survival rates at 2 years were 36.5% and 68.2%, respectively. Grade ≥ 3 hepatic toxicity was observed in one patient. Conclusions Two-week schedule of hypofractionated radiotherapy for small HCC was feasible with good local control and safety. This fractionation schedule can be used as an alternative treatment option for HCC located close to a critical normal organ if short-course SBRT is not feasible. [ABSTRACT FROM AUTHOR]

Introduction Methods Results Conclusion We investigated the clinical outcomes of stereotactic body radiation therapy (SBRT) alone versus SBRT after incomplete transarterial chemoembolization (TACE) for a single recurrent hepatocellular carcinoma (HCC) smaller than 5 cm.We retrospectively reviewed the medical records of patients who underwent SBRT for a single recurrent HCC ≤5 cm, without vascular invasion or extrahepatic metastasis. Patients were divided into the SBRT‐alone group and the TACE‐SBRT group. The primary outcome was the local control (LC) rate, and secondary outcomes were survivals and treatment‐related toxicities. We additionally conducted a propensity score matching (PSM) analysis.A total of 477 patients were available for analysis. Among them, 54 patients received SBRT without prior treatment to the target lesion (SBRT‐alone group), whereas 423 patients received SBRT for viable HCC after TACE (TACE‐SBRT group). The 3‐year LC rates did not differ between the two groups (SBRT‐alone group, 88.6% vs. TACE‐SBRT group, 89.6%, P = 0.918). The 3‐year rates of overall survival, out‐of‐field intrahepatic recurrence‐free survival and recurrence‐free survival were also not significantly different (P = 0.479, 0.290 and 0.273, respectively). Even after PSM, LC and survival rates at 3 years were not significantly different.SBRT alone demonstrated comparable local control and survival outcomes to SBRT following incomplete TACE. SBRT alone may be considered an alternative treatment option for a single recurrent HCC smaller than 5 cm when curative treatments or TACE are not feasible. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effective dose and patterns of recurrence after stereotactic body radiation therapy (SBRT) for hepatic metastases that arise from colorectal cancer.Methods and Materials: A cohort of 70 patients with 103 colorectal liver metastases were treated with SBRT at a single institution. The prescribed doses were 45 to 60 Gy in 3 to 4 fractions, but these were modified according to the tolerance of the adjacent normal tissue. To allow for dose comparisons, a biological equivalent dose was calculated.Results: The median follow-up period was 34.2 months (range, 5.3-121.8 months). The 2-year overall survival and progression-free survival rates were 75% and 35%, respectively. In subgroups, the 2-year local control rates for biological equivalent dose ≤80 Gy (group 1), 100 to 112 Gy (group 2), and ≥132 Gy (group 3) were 52%, 83%, and 89%, respectively. Cox proportional hazards model revealed a significant difference between groups (hazard ratio 0.44, P=.03 for group 2; hazard ratio 0.17, P=.17 for group 3; P=.01 for total). The major pattern of failure was a new liver metastasis out of the SBRT field. There was no grade ≥3 toxicity.Conclusions: Stereotactic body radiation therapy of liver metastases derived from colorectal cancer offers a locally effective treatment without significant complications. Longer local control can be expected if higher doses are used. Further studies will be needed to compare the efficacies of SBRT with those of surgical resection or radiofrequency ablation. [ABSTRACT FROM AUTHOR]