Study Of Stereotactic Body Radiation Therapy Research Articles

Phase I/II study of stereotactic body radiotherapy boost in patients with cervical cancer ineligible for intracavitary brachytherapy.

Stereotactic body radiotherapy (SBRT) boost is a promising treatment for cervical cancer patients who are ineligible for intracavitary brachytherapy (ICBT). The aim of this multicenter, single-arm, phase I/II study was to prospectively evaluate the efficacy and toxicity of SBRT boost. ICBT-ineligible patients with untreated cervical cancer were enrolled. Patients underwent whole-pelvic radiotherapy (45Gy in 25 fractions) with SBRT boost to the primary lesion. In the phase I dose-escalation cohort (3 + 3 design), patients were treated with SBRT boost of 21 or 22.5Gy in three fractions. Although dose-limiting toxicity was not confirmed, a dose of 21Gy was selected for the phase II cohort because it was difficult to reproduce the pelvic organs position in two patients during the phase I trial. The primary endpoint was 2-year progression-free survival. Twenty-one patients (phase I, n = 3; phase II, n = 18) were enrolled between April 2016 and October 2020; 17 (81%) had clinical stage III-IV (with para-aortic lymph node metastases) disease. The median (range) follow-up was 40 (10-84) months. The initial response was complete response in 20 patients and partial response in one patient. The 2-year locoregional control, progression-free survival, and overall survival rates were 84%, 67%, and 81%, respectively. Grade ≥ 3 toxicity was confirmed in one patient each in the acute (diarrhea) and late (urinary tract obstruction) phases. These findings suggested that a SBRT boost is more effective than the conventional EBRT boost and can be an important treatment option for ICBT-ineligible patients with cervical cancer. This study was registered at the University Hospital Medical Information Network Clinical Trials Registry (UMIN000036845).

Multicenter Retrospective Study of Stereotactic Body Radiotherapy for Patients with Previously Untreated Initial Small Hepatocellular Carcinoma.

The effectiveness of stereotactic body radiation therapy (SBRT) for hepatocellular carcinoma (HCC) has been shown in many studies and its therapeutic effect is similar to radiofrequency ablation (RFA). However, many of these studies were done in combination with transcatheter chemoembolization (TACE), for recurrent HCC, or on a small scale. To better understand the specific outcomes of SBRT for HCC, we conducted a multicenter retrospective analysis of SBRT for previously untreated initial HCC at Japanese Society of Clinical Oncology (JCOG) member hospitals. Patientswho underwent SBRT for HCC at JCOG member hospitals between July 2013 and December 2017 and met the following eligibility criteria were included: (1) initial HCC; (2) ≤ 3 nodules, ≤ 5 cm in diameter; (3) a Child-Pugh (CP) score of A or B; and (4) unsuitability for or refusal of standard treatment, such as surgery, transplantation, RFA and TACE. We evaluated the overall survival (OS), recurrence-free survival (RFS) which was defined as the first instance of intra-hepatic recurrence after SBRT, disease-specific survival (DSS) using Kaplan-Meier analysis. Using Grey's test, patients who died of other diseases were analyzed as competing risks to estimate the cumulative incidence of local recurrence (CLR). Adverse events directly related to SBRT also analyzed using Common Terminology Criteria for Adverse Events version 5.0 (CTCAE v5.0). Seventy-three patients with 79 lesions from 14 hospitals were analyzed. The median age was 77 years (range; 50-89 years), and the median tumor size was 23 mm (range; 6-50 mm). The median radiation dose was 40 Gy (range; 35-60 Gy) in five fractions (range; 4-8). The median follow-up period was 45 months (range; 0-103 months). There were three cases where follow-up was not possible due to unexpected events unrelated to SBRT, while the remaining 70 patients were successfully followed for at least six months. The 2 and 3year OS, RFS, DSS, and CLR rates were 84.3% (95% CI: 75.8-92.8%) and 69.9% (95% CI: 58.7-81%), 67.5% (95% CI: 56.0-79.0%) and 57.9% (95% CI: 45.2-70.5%), 95.1% (95% CI:89.7-100%)/87.6% (95% CI:78.8-96.3%), and 11.4% (95% CI: 5.3-20.0%) and 20.0% (95% CI: 11.2-30.5%), respectively. Four cases (5.5%) of adverse events of grade 3 or higher were reported: one case of grade 3 laboratory toxicities, one case of grade 3 liver failure, one case of grade 3 portal tumor thrombosis, and one case of grade 4 duodenal ulcer. No grade 5 toxicities were observed. The results of our study demonstrate that SBRT for HCC is highly effective in achieving local control and is safe to administer. In addition, survival outcomes are favorable. SBRT is a promising treatment modality, especially for small HCCs for that is not suitable for standard treatment.

A pilot study of stereotactic body radiotherapy combined with pelvic radiotherapy and GTVp boost based on multiparameter magnetic resonance image in patients with high-risk prostate cancer.

This pilot study aimed to explore the preliminary effects and safety of stereotactic body radiotherapy (SBRT) combined with preventive pelvic radiotherapy and primary gross tumor volumes (GTVp) boost in patients with high-risk prostate cancer based on multiparameter magnetic resonance image (mpMRI). Tumors were contoured as GTVp based on mpMRI. The prostate and proximal seminal vesicles were considered as the clinical target volume1. The pelvic lymphatic drainage area constituted clinical target volume 2. Radiation doses were 40Gy or 45Gy/5fractions to planning target volume of primary tumor, 37.5Gy/5f to prostate, seminal vesicle, and positive pelvic lymph nodes, and 25Gy/5f to pelvic synchronously. The treatment was delivered 3 times per week. Volumetric modulated arc radiotherapy and intensity-modulated radiotherapy were used to complete SBRT. The genitourinary (GU) and gastrointestinal (GI) toxicities were evaluated. Quality of life data was also captured. A total of 15 patients were enrolled in this study with a median age of 78 (56-87) from 2017 to 2020. All patients received SBRT. At 3 months after radiotherapy, the proportion of PSA < 0.006 ng/mL was 66.7% (10/15). The 2-year biochemical relapse-free survival was 93.3%. The incidence of grade 1 acute GU side effects was 80% (12/15); the incidence of acute grade 1 GI toxicity was 66.7% (10/15); and no grade 2 or higher acute GU and GI side effects was observed. Two patients presented with temporary late grade 2 GI toxicity. International Prostatic System Score increased rapidly after a transient increase at 1 week (P = .001). There were no significant differences in EORTC quality of life scores in all domains except global health status. In this pilot study, it was revealed that SBRT combined with preventive pelvic radiotherapy and GTVp boost based on mpMRI image was effective and well tolerated for patients with high-risk prostate cancer.

A Pilot Study of Stereotactic Body Radiotherapy and 177Lu-PSMA-617 for Oligometastatic Hormone Sensitive Prostate Cancer

Stereotactic body radiotherapy (SBRT) is increasingly used for oligorecurrent prostate cancer (OPC). Despite excellent local control, distant metastasis free survival rates are more modest. We hypothesized SBRT outcomes could be optimized with improved staging imaging and integration of a well-tolerated targeted radiopharmaceutical therapy (RLT) for microscopic disease. We report initial results of a prospective, single-institution pilot (NCT05079698) of a novel, PSMA-based theranostic strategy for OPC. Men with castrate sensitive OPC and 1-3 sites of PSMA PET avid disease ("index lesions") and no PSMA non-avid sites were eligible. No androgen deprivation therapy was permitted. Subjects first received 2 cycles of 177Lu-PSMA-617 RLT (7.47±0.14 GBq) spaced 6 weeks apart. In vivo dosimetry was performed during cycle 1. Four weeks post-cycle 2, patients were restaged with 68Ga-PSMA PET for an interim (post-RLT) response assessment. Index lesions were then consolidated with SBRT (9 Gy x 3) irrespective of post-RLT PET response. The primary outcome was feasibility defined as successful completion of protocol-mandated therapy without intercurrent distant failure on post-RLT PET. Six men were treated with nine total index lesions (5 nodal, 3 osseous, 1 visceral). The study met its primary endpoint; all completed required interventions and no distant progression was seen on interim PSMA PET. Treatment was well tolerated; no grade 3+ toxicities, 2/6 had grade 2 toxicities (transient anemia and hyperbilirubinemia) and 5/6 had grade 1 toxicities. Median baseline lesion-level PSMA SUVmax was 16.8±8.7. Median interim SUVmax was 6.2±2.5 and declined for all but one lesion post-RLT (median -65%). Median SUVmax at 3-mos post-SBRT was 3.3±2.5 and decreased for all evaluable lesions (median -80%). Median baseline PSA was 2.01 ng/mL (range: 0.72-4.56) which declined in 5/6 post-RLT. The 6th patient experienced biochemical rise with interim PET showing only greater avidity in the known index lesion and SBRT was completed per protocol. All 4 evaluable patients with at least one post-SBRT follow-up have improved PSA at last visit (range 5.5-12 mos from cycle 1), and 2/4 have undetectable PSA. Composite dosimetry, correlatives and quality of life studies are forthcoming. Our pilot study demonstrates the feasibility of a novel PSMA anchored theranostic strategy combining SBRT with targeted RLT for OPC. Preliminary data suggests promising outcomes, including the possibility of achieving an undetectable biochemical disease state without hormone therapy.

Effect of hypofractionated radiotherapy, PD-1 immunotherapy, and anti-angiogenic therapy on abscopal responses and the tumor microenvironment.

e14609 Background: Hypofractionated radiotherapy (HFRT) of the primary tumor can induce abscopal effects in metastatic cancer, which could be enhanced by adding PD-1 immunotherapy (IO) and low-dose radiotherapy (LDRT) of distant disease. However, this strategy remains with suboptimal efficacy. Translational research has shown that LDRT primarily modulates the immune microenvironment of tumors in the irradiated area, a mechanism shared by anti-angiogenic therapy (AAT). Therefore, this study aimed to compare the efficacy (abscopal responses and cytokine levels in the tumor microenvironment) between HFRT+IO+AAT and HFRT+IO+LDRT. Methods: Bilateral mouse tumor models were divided into seven groups for various treatments (Table 1). After treatment, blood and tumor samples of mice were collected for analysis. We evaluated clinical effects of HFRT+IO+AAT in 4 patients with unirradiated lung metastases in a currently-accruing phase Ib study of stereotactic body radiotherapy (SBRT) plus anlotinib (AAT) with or without toripalimab (PD-1 IO) in driver mutation-negative non-small cell lung cancer (NCT05021328). Results: The results of animal studies are shown in Table 1. HFRT to the primary tumor combined with AAT and IO enhanced the abscopal response in secondary tumor compared to HFRT, HFRT+IO, HFRT+AAT, IO+AAT, as well as HFRT+LDRT+IO. The most noteworthy secondary tumor control was observed in mice receiving HFRT+IO+AAT. The enhanced abscopal responses were associated with increased infiltration of CD8+ effector T cells, increased expression of IFN-γ and levels of TNF-α. From the prospective trial population, 4 unirradiated lung lesions in the HFRT+IO+AAT cohort decreased by an average of 48% in size (n=3 partial response, n=1 stable disease). No grade 3 treatment-related toxicity was observed. Conclusions: HFRT+IO+AAT is a promising therapeutic combination that may optimize abscopal responses, potentially even further than HFRT+LDRT+IO. This new “triple therapy” was safe and efficacious in patients and deserves further study. [Table: see text]

Multicenter retrospective study of stereotactic body radiotherapy for patients with previously untreated initial small hepatocellular carcinoma.

We aimed to verify the therapeutic efficacy and safety of stereotactic body radiotherapy (SBRT) for previously untreated initial small hepatocellular carcinoma (HCC) in a multicenter, retrospective study. Patients who underwent SBRT for HCC at the Japanese Society of Clinical Oncology (JCOG) member hospitals in Japan between July 2013 and December 2017 and met the following eligibility criteria were included: (1) initial HCC; (2) ≤3 nodules, ≤5cm in diameter; (3) Child-Pugh score of A or B; and (4) unsuitability for or refusal of standard treatment. We analyzed the overall survival, recurrence-free survival, and cumulative incidence of local recurrence rate, and adverse events directly related to SBRT. Seventy-three patients with 79 lesions from 14 hospitals were analyzed. The median age was 77years (range: 50-89years), and the median tumor size was 23mm (range: 6-50mm). The median radiation dose was 40Gy (range: 35-60Gy) in five fractions (range: 4-8). The median follow-up period was 45months (range: 0-103months). The 3-year overall survival, recurrence-free survival, and cumulative incidence of local recurrence rates were 69.9% (95% CI: 58.7%-81%), 57.9% (95% CI: 45.2%-70.5%), and 20.0% (95% CI: 11.2%-30.5%), respectively. Four cases (5.5%) of adverse events of grade 3 or higher were reported: three cases of grade 3 and one case of grade 4 (duodenal ulcer). No grade 5 toxicities were observed. SBRT is a promising treatment modality, particularly for small HCCs, as they are not suitable for standard treatment.

Final Analysis of Consolidative Use of Radiotherapy to Block (CURB) Oligoprogression Trial - A Randomized Study of Stereotactic Body Radiotherapy for Oligoprogressive Metastatic Lung and Breast Cancers

Final Analysis of Consolidative Use of Radiotherapy to Block (CURB) Oligoprogression Trial - A Randomized Study of Stereotactic Body Radiotherapy for Oligoprogressive Metastatic Lung and Breast Cancers

A Cost-Effectiveness Study of Stereotactic-Body Radiation Therapy Compared to Surgery in Patients with Early Non-Small Cell Lung Cancer, from the Perspective of the Brazilian Private Health-Care System

<h3>Purpose/Objective(s)</h3> The standard of care for operable stage I non-small cell lung cancer (NSCLC) is lobectomy with mediastinal lymph node dissection. Stereotactic body radiotherapy (SBRT) has shown promising results in non-operable patients. Previous randomized trials, comparing those technologies, were closed early due to poor accrual, but pooled results have indicated that they are, at least, equally effective. Further trials were opened, and results are waited for the following years to come. The objective of this study was to evaluate the cost-effectiveness of SBRT, compared to lobectomy, in operable stage I NSCLC. <h3>Materials/Methods</h3> A Markov model was built based on the pooled analysis of two previous prospective randomized trials. Costs, in reais (BRL), were extracted from the database of a Brazilian nationwide health care provider (Capesesp). Utility values, recurrence, and death probabilities were adapted from the literature. The analysis was conducted from the Brazilian healthcare private system perspective. A 10 years' time horizon was used in the study. A yearly discount rate of 5% was applied, according to Brazilian regulatory authorities' recommendations. Deterministic (DSA) and probabilistic sensitivity analysis (PSA) were performed to evaluate the influence on the results of the assumptions that were made. <h3>Results</h3> SBRT and lobectomy total costs were 93,207.00 and 115,776.00 BRL and utilities were 2.72 and 2.55 QALYs (quality-adjusted life-years), respectively, showing that SBRT was dominant over surgery, with an incremental cost-effectiveness ratio (ICER) of -134,445.27 BRL. The DSA, performed based on every made assumption, showed that results depended mainly on the probability of progression after lobectomy, on the cost of chemotherapy, prescribed for patients that presented progression after both curative treatments, and on the probability of recurrence after SBRT. PSA revealed that SBRT had a considerably higher probability of being cost-effective, compared to lobectomy. <h3>Conclusion</h3> our results indicate that for patients with stage I, operable, NSCLC, SBRT is probably dominant over lobectomy. Sensitivity analysis has shown that those results are robust and not modified by the assumptions that were made during the construction of the model. It raises the importance of the open trials comparing those technologies, once SBRT can be a viable cost-saving option, in our environment, if its effectiveness is proven to be, at least, comparable to surgery.

KEYNOTE-867: Phase 3, Randomized, Placebo-Controlled Study of Stereotactic Body Radiotherapy (SBRT) with or without Pembrolizumab in Patients with Unresected Stage I or II Non–Small-Cell Lung Cancer (NSCLC)

<h3>Purpose/Objective(s)</h3> Anti–PD-(L)1-directed therapy following radiotherapy or following concurrent chemoradiation is associated with significantly longer PFS and OS in patients with advanced or metastatic NSCLC, including those with locally advanced inoperable tumors. KEYNOTE-867 (NCT03924869) evaluates the efficacy and safety of SBRT with or without pembrolizumab in patients with unresected stage I or II NSCLC. <h3>Materials/Methods</h3> In this phase 3, randomized, placebo-controlled study, approximately 530 adult patients with previously untreated, unresected, histologically/cytologically confirmed stage I or II (T1 to limited T3, N0, M0) NSCLC are randomized 1:1 to receive thoracic SBRT to primary tumors for ≤2 wk (Table) and either pembrolizumab 200 mg or placebo every 3 wk for 17 cycles (approximately 1 year) or until disease recurrence, development of unacceptable AEs, SBRT not started for any reason, or study withdrawal. Randomization is stratified by disease stage (I vs II), ECOG PS (0 or 1 vs 2), geographic region (East Asia vs non-East Asia), and reason for not receiving surgery (medically inoperable vs refused surgery). Imaging assessment by blinded independent central review (BICR) occurs at 12 wk (≥10 wk after SBRT completion), followed by every 16 wk for 3 y, and then every 6 mo. Primary endpoints are event-free survival (EFS) by BICR and OS. Secondary endpoints include time to death or distant metastases and safety; exploratory endpoints are time to subsequent treatment, disease-specific survival, and time to recurrence/progression on subsequent line of therapy. AEs are monitored throughout the trial until 30 d after last dose (90 for serious AEs) and graded according to NCI CTCAE version 4.0. EFS and OS are analyzed by the nonparametric Kaplan-Meier method, treatment differences by stratified log-rank test, and hazard ratios by stratified Cox proportional hazard model with Efron's method of tie handling. Enrollment started on June 17, 2019, and is ongoing at 169 sites in North America, South America, Europe, Asia and Australasia. <h3>Results</h3> TBD <h3>Conclusion</h3> TBD

A Prospective Study of Stereotactic Body Radiotherapy (SBRT) with Concomitant Whole-Pelvic Radiotherapy (WPRT) for High-Risk Localized Prostate Cancer Patients Using 1.5 Tesla Magnetic Resonance Guidance: The Preliminary Clinical Outcome.

Simple SummaryMagnetic resonance (MR)-guided stereotactic body radiotherapy (MRgSBRT) with concomitant whole-pelvic nodal radiotherapy (WPRT) represents a novel radiotherapy paradigm for high-risk prostate cancer (HR-PC), potentially improving online image guidance and clinical outcomes. This is the first prospective study aims to report the preliminary clinical experiences and treatment outcome of 1.5 Tesla adaptive MRgSBRT with concomitant WPRT in HR-PC patients (72.5 ± 6.8 years). Forty-two consecutive localized HR-PC patients were treated by online adaptive MRgSBRT (8 Gy(prostate)/5 Gy(WPRT) × 5 fractions) combined with androgen deprivation therapy (ADT) and followed up (median: 251 days, range: 20–609 days). The maximum cumulative acute gastrointestinal (GI)/ genitourinary (GU) grade 1 and 2 toxicity rates were 19.0%/81.0% and 2.4%/7.1%, respectively. The subacute (>30 days) GI/GU grade 1 and 2 toxicity rates were 21.4%/64.3% and 2.4%/2.4%, respectively. No grade 3 toxicities were reported. Patient-reported quality of life (QoL) showed insignificant changes in urinary, bowel, sexual, and hormonal domain scores during the follow-up period. All patients had early post-MRgSBRT biochemical responses, while biochemical recurrence (prostate-specific antigen nadir + 2 ng/mL) occurred in one patient at month 18. The early results suggested favorable treatment-related toxicities and encouraging patient-reported QoLs, but long-term follow-up is still needed. Background: Conventionally fractionated whole-pelvic nodal radiotherapy (WPRT) improves clinical outcome compared to prostate-only RT in high-risk prostate cancer (HR-PC). MR-guided stereotactic body radiotherapy (MRgSBRT) with concomitant WPRT represents a novel radiotherapy (RT) paradigm for HR-PC, potentially improving online image guidance and clinical outcomes. This study aims to report the preliminary clinical experiences and treatment outcome of 1.5 Tesla adaptive MRgSBRT with concomitant WPRT in HR-PC patients. Materials and methods: Forty-two consecutive HR-PC patients (72.5 ± 6.8 years) were prospectively enrolled, treated by online adaptive MRgSBRT (8 Gy(prostate)/5 Gy(WPRT) × 5 fractions) combined with androgen deprivation therapy (ADT) and followed up (median: 251 days, range: 20–609 days). Clinical outcomes were measured by gastrointestinal (GI) and genitourinary (GU) toxicities according to the Common Terminology Criteria for Adverse Events (CTCAE) Scale v. 5.0, patient-reported quality of life (QoL) with EPIC (Expanded Prostate Cancer Index Composite) questionnaire, and prostate-specific antigen (PSA) responses. Results: All MRgSBRT fractions achieved planning objectives and dose specifications of the targets and organs at risk, and they were successfully delivered. The maximum cumulative acute GI/GU grade 1 and 2 toxicity rates were 19.0%/81.0% and 2.4%/7.1%, respectively. The subacute (>30 days) GI/GU grade 1 and 2 toxicity rates were 21.4%/64.3% and 2.4%/2.4%, respectively. No grade 3 toxicities were reported. QoL showed insignificant changes in urinary, bowel, sexual, and hormonal domain scores during the follow-up period. All patients had early post-MRgSBRT biochemical responses, while biochemical recurrence (PSA nadir + 2 ng/mL) occurred in one patient at month 18. Conclusions: To our knowledge, this is the first prospective study that showed the clinical outcomes of MRgSBRT with concomitant WPRT in HR-PC patients. The early results suggested favorable treatment-related toxicities and encouraging patient-reported QoLs, but long-term follow-up is needed to confirm our early results.

Phase 3, randomized, placebo-controlled study of stereotactic body radiotherapy (SBRT) with or without pembrolizumab in patients with unresected stage I or II non–small cell lung cancer (NSCLC): KEYNOTE-867.

TPS8597 Background: Anti–PD-(L)1-directed therapy following radiotherapy or following concurrent chemoradiation is associated with significantly longer PFS and OS in patients with advanced or metastatic NSCLC, including those with locally advanced inoperable tumors. KEYNOTE-867 (NCT03924869) evaluates the efficacy and safety of SBRT with or without pembrolizumab in patients with unresected stage I or II NSCLC. Methods: In this phase 3, randomized, placebo-controlled study, approximately 530 adult patients with previously untreated, unresected, histologically/cytologically confirmed stage I or II (T1 to limited T3, N0, M0) NSCLC are randomized 1:1 to receive thoracic SBRT to primary tumors for ≤2 wk (Table) and either pembrolizumab 200 mg or placebo every 3 wk for 17 cycles (approximately 1 year) or until disease recurrence, development of unacceptable AEs, SBRT not started for any reason, or study withdrawal. Randomization is stratified by disease stage (I vs II), ECOG PS (0 or 1 vs 2), geographic region (East Asia vs non-East Asia), and reason for not receiving surgery (medically inoperable vs refused surgery). Imaging assessment by blinded independent central review (BICR) occurs at 12 wk (≥10 wk after SBRT completion), followed by every 16 wk for 3 y, and then every 6 mo. Primary endpoints are event-free survival (EFS) by BICR and OS. Secondary endpoints include time to death or distant metastases and safety; exploratory endpoints are time to subsequent treatment, disease-specific survival, and time to recurrence/progression on subsequent line of therapy. AEs are monitored throughout the trial until 30 d after last dose (90 for serious AEs) and graded according to NCI CTCAE version 4.0. EFS and OS are analyzed by the nonparametric Kaplan-Meier method, treatment differences by stratified log-rank test, and hazard ratios by stratified Cox proportional hazard model with Efron's method of tie handling. Enrollment started on June 17, 2019, and is ongoing at 168 sites around the world. Clinical trial information: NCT03924869. [Table: see text]

A phase II study of stereotactic body radiotherapy (SBRT) combined with sintilimab in patients with recurrent or oligometastatic hepatocellular carcinoma (HCC).

4071 Background: SBRT is an emerging treatment option for oligometastatic cancer disease. Preclinical studies have shown the synergistic effects between the radiotherapy and immunotherapy. Early clinical data also suggested that immunotherapy might augment the local effects of radiotherapy and decrease metastatic recurrence. This study aimed to evaluate the efficacy and safety of SBRT combined with sintilimab (a PD-1 antibody) in patients with recurrent or oligometastatic HCC. Methods: In this single arm, phase II study (NCT03857815), eligibility criteria included Pts with recurrent or oligometastatic HCC (defined as ≤5 metastatic/recurrent lesions), Child-Pugh class A, ECOG PS ≤ 1. Pts received sintilimab 200 mg IV Q3W for up to 12 months, progressive disease, unacceptable toxicity, or withdrawal. SBRT to all lesions was started at cycle 1 day 1. Primary endpoint was progression free survival (PFS) per RECIST 1.1. Secondary endpoints included safety, objective response rate (ORR), disease control rate (DCR) and overall survival (OS). Results: At data cutoff (Dec 28th, 2021), 25 pts with 32 lesions were treated with SBRT + Sintilimab. SBRT was delivered at a median dose of 54 Gy (range 48-60) in 6 fractions (range 6-10) and the median follow-up time was 16.9 months (range 3.9-32.1). In those 25 evaluable pts, median age was 64 years (range 37-77), 24 (96%) were male, 24 (96%) were HBV+, 6 (24%) had extrahepatic metastasis, most pts had prior ≥2 local therapies. The confirmed ORR was 96% (24/25) according to RECIST 1.1 with 18pts CR and 6pts PR. 6-mo and 12-mo PFS rate was 100% and 70% (95%CI, 52.3%-93.6%), respectively.12-mo local control rate was 100%. Median PFS and OS was still not mature. Treatment-related adverse events (TRAEs) occurred in 14 pts (56%). Most common TRAEs were rash (16%), platelet count decreased (12%), myositis (8%). Grade 3 TRAEs (myositis) occurred in 1pt (4%). There were no grade 4-5 TRAEs. TRAEs led to discontinuation in 6 pts (24%). SAE were myocarditis (1pt Grade1), viral hepatitis (1pt Grade 3, treatment-independent) and upper gastrointestinal haemorrhage (1pt Grade 3, PD related). Conclusions: The combination of SBRT with Sintilimab was tolerable and showed an encouraging ORR of 96% in pts with recurrent or oligometastatic HCC. Longer follow up is required to further evaluate the efficacy and safety. Clinical trial information: NCT03857815.

A phase II trial of stereotactic body radiotherapy in 4 fractions for patients with localized prostate cancer

Purpose/objective(s)To report results from our phase II study of stereotactic body radiotherapy (SBRT) delivering 36 Gy in 4 fractions for patients with localized prostate cancer.Materials/methodsWe enrolled 55 patients treated with SBRT delivering 36 Gy in 4 fractions between 2015 to 2018. All patients were categorized as low-risk (n = 4), intermediate-risk (n = 31) or high-risk (n = 20) according to National Comprehensive Cancer Network criteria. Median age was 73 years (range 54–86 years). Two-thirds of patients (n = 37) had received androgen-deprivation therapy for 3–46 months (median, 31 months). Median duration of follow-up was 36 months (range 1–54 months). We used Radiation Therapy Oncology Group and National Cancer Institute—Common Toxicity Criteria version 4 for toxicity assessments. Quality of life (QOL) outcomes were also evaluated using the Expanded Prostate Cancer Index Composite (EPIC).ResultsProtocol treatments were completed for all patients. Six patients experienced biochemical failures. Among these six patients, three patients experienced clinical failure. One patient showed bone metastasis before biochemical failure. One patient died of gastric cancer. The 3-year biochemical control rate was 89.8%. Acute grade 2 genitourinary (GU) and gastrointestinal (GI) toxicities were observed in 5 patients (9%) and 6 patients (11%), respectively. No grade 3 or higher acute toxicities were observed. Late grade 2 GU and GI toxicities were observed in 7 patients (13%) and 4 patients (7%), respectively. Late grade 3 GU and GI toxicities were observed in 1 patient (1.8%) each. EPIC scores decreased slightly during the acute phase and recovered within 3 months after treatment.ConclusionOur phase II study showed that SBRT delivering 36 Gy in 4 fractions was safe and effective with favorable QOL outcomes, although this regimen showed slightly more severe toxicities compared to current standards.

Consolidative Use of Radiotherapy to Block (CURB) Oligoprogression ― Interim Analysis of the First Randomized Study of Stereotactic Body Radiotherapy in Patients With Oligoprogressive Metastatic Cancers of the Lung and Breast

<h3>Purpose/Objective(s)</h3> We hypothesize that there is an oligoprogressive state in metastatic cancer, in which disease control can be improved with local therapy to progressive lesions only. This study therefore evaluated the impact of stereotactic body radiotherapy (SBRT) to sites of oligoprogression in patients with metastatic non-small-cell lung cancer (NSCLC) and breast cancer with 1-5 progressive lesions. <h3>Materials/Methods</h3> We enrolled patients with metastatic NSCLC or breast cancer who received ≥ 1 line of systemic therapy and had oligoprogressive lesions amenable to SBRT. There was no upper limit of non-progressive lesions. Oligoprogression was defined as Response Evaluation or Positron Emission Tomography Response Criteria in Solid Tumors documented progression ≤ 5 individual lesions. Stratification factors included number of progressive sites (1 vs. 2-5), prior systemic therapy (immunotherapy vs. other), primary tumor (NSCLC vs. breast), and tumor marker status (driver mutation and hormone receptor status). Patients were randomized 1:1 between SBRT to all progressive sites plus palliative standard of care (SOC) vs. palliative SOC only. Systemic therapy was per physician's discretion. The primary endpoint was progression-free survival (PFS). We used a randomized phase II design with a one-sided alpha of 0.05 and a power of 0.80, yielding a target accrual of 160 patients. PFS was compared using one-sided stratified log-rank test. One interim analysis was planned. <h3>Results</h3> From January 2019 to May 2021, 102 patients were randomized - 58 NSCLC (30 in the SBRT arm) and 44 breast (22 in each arm). Median age was 67. Most patients (75%) had > 1 site of oligoprogression and 47% had > 5 total metastatic lesions. Fifty-five (54%) patients received immunotherapy. The majority of NSCLC (86%) did not harbor an actionable driver mutation and 32% of breast cancer were triple negative. Baseline factors were balanced between arms. At a median follow-up of 51 weeks, 71 patients progressed and 30 died. Median PFS was 22 weeks in the SBRT arm vs. 10 weeks in the palliative SOC arm (p=0.005). This was driven entirely by the PFS benefit from SBRT in the NSCLC patients (44 weeks with SBRT vs. 9 weeks with SOC; p=0.004). No difference in median PFS was seen in the breast cohort (18 weeks with SBRT vs. 17 weeks with SOC; p=0.5). In multivariable Cox model inclusive of stratification factors, age, sex, lines of systemic therapy, and change of systemic therapy, the PFS benefit of SBRT remained substantial in the NSCLC cohort (Hazard Ratio: 0.38; 95% CI: 0.18-77; p=0.007). Grade ≥2 adverse events occurred in 8 patients in the SBRT arm, including 1 grade 3 pneumonitis. <h3>Conclusion</h3> Inthis pre-planned interim analysis of the first and largest randomized trial of radiotherapy for oligoprogressive metastatic NSCLC and breast cancer, we demonstrated the benefit of SBRT to sites of oligoprogression on overall PFS, meeting the primary endpoint. The mechanism of the differential benefits between NSCLC and breast cohorts merits further evaluation.

Phase II study of stereotactic body radiotherapy with hydrogel spacer for prostate cancer: acute toxicity and propensity score-matched comparison

BackgroundThe efficacy of a hydrogel spacer in stereotactic body radiotherapy (SBRT) has not been clarified. We evaluated the safety and efficacy of SBRT in combination with a hydrogel spacer for prostate cancer.MethodsThis is a prospective single-center, single-arm phase II study. Prostate cancer patients without lymph node or distant metastasis were eligible. All patients received a hydrogel spacer insertion, followed by SBRT of 36.25 Gy in 5 fractions with volumetric modulated arc therapy. The primary endpoint was physician-assessed acute gastrointestinal (GI) toxicity within 3 months. The secondary endpoints were physician-assessed acute genitourinary (GU) toxicity, patient-reported outcomes evaluated by the EPIC and FACT-P questionnaires, and dosimetric comparison. We used propensity score-matched analyses to compare patients with the hydrogel spacer with those without the spacer. The historical data of the control without a hydrogel spacer was obtained from our hospital’s electronic records.ResultsForty patients were enrolled between February 2017 and July 2018. A hydrogel spacer significantly reduced the dose to the rectum. Grade 2 acute GI and GU toxicity occurred in seven (18%) and 17 (44%) patients. The EPIC bowel and urinary summary score declined from the baseline to the first month (P < 0.01, < 0.01), yet it was still significantly lower in the third month (P < 0.01, P = 0.04). For propensity score-matched analyses, no significant differences in acute GI and GU toxicity were observed between the two groups. The EPIC bowel summary score was significantly better in the spacer group at 1 month (82.2 in the spacer group and 68.5 in the control group).ConclusionsSBRT with a hydrogel spacer had the dosimetric benefits of reducing the rectal doses. The use of the hydrogel spacer did not reduce physician-assessed acute toxicity, but it improved patient-reported acute bowel toxicity.Trial registration: Trial registration: UMIN-CTR, UMIN000026213. Registered 19 February 2017, https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000029385.

Treatment outcomes of stereotactic body radiation therapy using a real-time tumor-tracking radiotherapy system for hepatocellular carcinomas.

To report the outcomes of stereotactic body radiotherapy using a real-time tumor-tracking radiotherapy system for hepatocellular carcinoma patients. From January 2005 to July 2018, 63 patients with 74 lesions with a maximum diameter ≤52mm were treated by stereotactic body radiotherapy using a real-time tumor-tracking radiotherapy system. No patient with a Child-Pugh Score ≥9 was included, and 85.6% had a score of 5 or 6. Using the biological effective dose (BED) with an α/β ratio of 10 (BED10 ), the median dose in BED10 at the reference point was 76.8Gy (range 60-122.5Gy). Overall survival (OS) and local control rates were assessed using the Kaplan-Meier method. With a median follow-up period of 24.6months (range 0.9-118.4months), the 1-year and 2-year OS rates were 86.8% (95% confidence interval [95% CI] 75.8-93.3) and 71.1% (57.8-81.6), respectively. The 2-year OS was 89.6% in patients with the baseline modified albumin-bilirubin (mALBI) grade =1, and 61.7% in patients with grade ≥2a. In the multivariate analysis, the mALBI grade (=1 vs. ≥2a) was a significant factor for OS (p=0.028, 95% CI 1.11-6.18). The 1-year and 2-year local control rates were 100% (100-100%) and 92.0% (77.5-97.5%). The local control rates were significantly higher in the BED10 ≥100Gy group than in the BED10 <100Gy group (2-year 100% vs. 86.5%, p=0.049) at the reference point. This retrospective study of stereotactic body radiotherapy using real-time tumor-tracking radiotherapy for hepatocellular carcinoma showed favorable outcomes with lower incidence of toxicities, especially in patients treated with BED10 ≥100Gy to the reference point.

Multicenter prospective study of stereotactic body radiotherapy for previously untreated solitary primary hepatocellular carcinoma: The STRSPH study.

To prospectively evaluate the efficacy and safety of stereotactic body radiotherapy (SBRT) for patients with previously untreated solitary primary hepatocellular carcinoma (HCC). The main eligibility criteria included the following: (1) primary solitary HCC; (2) no prior treatment for HCC; (3) Child-Turcotte-Pugh score of seven or less; and (4) unsuitability for or refusal of surgery and radiofrequency ablation (RFA). The prescribed dose of SBRT was 40Gy in five fractions. The primary endpoint was 3-year overall survival (OS); the secondary endpoints included local progression-free survival (LPFS), local control (LC), and adverse events. The accrual target was 60 patients, expecting a 3-year OS of 70% with a 50% threshold. Between 2014 and 2018, 36 patients were enrolled; enrollment was closed early because of slow accrual. The median tumor size was 2.3cm. The median follow-up at the time of evaluation was 20.8months. The 3-year OS was 78% (95% confidence interval [CI]: 53%-90%). The 3-year LPFS and LC proportion were 73% (95% CI: 48%-87%) and 90% (95% CI: 65%-97%), respectively. Grade 3 or higher SBRT-related toxicities were observed in four patients (11%), and grade five toxicities were not observed. This study showed acceptably low incidence of SBRT-related toxicities. LC and OS after SBRT were comparable for previously untreated solitary HCC for patients unfit for resection and RFA. Although a definitive conclusion cannot be drawn by this study, the promising results indicate that SBRT may be an alternative option in the management of early HCC.

P05.01 Multicenter Retrospective Study of Stereotactic Body Radiotherapy in Non-Small Cell Lung Cancer in South Korea (KROG 17-09)

P05.01 Multicenter Retrospective Study of Stereotactic Body Radiotherapy in Non-Small Cell Lung Cancer in South Korea (KROG 17-09)

PO-0993: Multicenter study of stereotactic body radiotherapy in non-small cell lung cancer (KROG 17-09)

PO-0993: Multicenter study of stereotactic body radiotherapy in non-small cell lung cancer (KROG 17-09)

Phase I Study of Stereotactic Body Radiotherapy followed by Ipilimumab with Nivolumab vs. Nivolumab alone in Unresectable Hepatocellular Carcinoma

Phase I Study of Stereotactic Body Radiotherapy followed by Ipilimumab with Nivolumab vs. Nivolumab alone in Unresectable Hepatocellular Carcinoma