Outcomes Of Stereotactic Body Radiotherapy Research Articles

Stereotactic ablative radiotherapy for oligometastatic prostate cancer.

The present study assessed clinical outcomes of stereotactic body radiotherapy (SBRT) in oligometastatic prostate cancer patients. Between 2017 and 2020, 37 lesions (12 osseous and 25 nodal targets) detected with conventional and/or functional imaging, were treated in 29 patients (pts), in different clinical settings: de novo oligometastatic (2 pts), oligorecurrent castration-sensitive (19 pts), castration-resistant (6 pts) prostate cancers and oligoprogressive disease during systemic therapy (2 pts). SBRT was delivered with volumetric modulated arc therapy up to a total dose of 21 Gy given in 3 fractions for bone and 30 Gy in 5 fractions for nodal metastases. A total of 34% of pts received hormonal therapy. We evaluated biochemical control [prostate serum antigen (PSA) increase < 10%)], progression free-survival (PFS) (time from SBRT to biochemical progression), local control (LC) (time from SBRT to in-field radiologic progression), hormone/systemic therapy-free survival, acute and late toxicities. At 3 months, biochemical response was observed in 20/29 pts (69%). At a median follow-up of 17 months (range 6-33), 8/20 (40%) of the 3-month responders remained free from progression. Two-year PFS and LC were 37% and 70%, respectively. In-field progression occurred in 3/37 (8%) lesions. Hormone/systemic therapy was delayed by an average of 11.6 months (range 3-28). No significant difference in PFS based on the type of lesion or concomitant endocrine therapy was observed and no toxicity > grade 2 was reported. SBRT for oligometastatic prostate cancer offers a good biochemical/local control and tangible delay of hormone/systemic therapy without major toxicities.

Impact of Time-to-Treatment on Lung SBRT Outcomes: Histology Matters!

<h3>Purpose/Objective(s)</h3> "Time-to-treatment" (TTT) is considered an indicator of quality care that has been postulated to affect lung cancer outcomes. The process by which an early stage medically inoperable lung cancer patient (pt) is deemed appropriate for lung stereotactic body radiation therapy (SBRT) typically involves a multi-disciplinary assessment over extended time. This study analyzed a large single institution registry to explore the impact of TTT on SBRT outcomes. <h3>Materials/Methods</h3> From an IRB-approved lung SBRT registry, we identified 1573 pts treated definitively for early-stage lung cancer between 2003 and 2020. TTT was defined as elapsed months between date of diagnosis (date of biopsy or date of PET CT in cases of radiographic diagnosis) and SBRT start date. Fine-Gray's Test was employed to evaluate the effect of TTT on local control (LC) and freedom from disease progression (FFP), and the long rank test was used for overall survival (OS). Cumulative incidence rates with death as competing event were calculated for LC and FFP. Actuarial analysis as used to calculate OS rates. <h3>Results</h3> Median follow-up was 22.9 months. Median age at SBRT start in years was 74.5 (range 35-98), median KPS was 80 (range 40-100), 52.3% of pts were female and 84.0% were white. Median tumor size and median PET SUV max were 2.2 cm (range 0.4-10.5) and 7.5 (range 0.8-56), respectively; 88.3% of pts were stage I. Of 75.7% pts with biopsies, 30.6% were adenocarcinomas (AC), 27.8% had squamous carcinoma (SqC). Median SBRT dose was 50 Gy in 5 fractions (40.5% cases). The 2-year rates of LC, FFP and OS for all pts were 6.5%, 76.3%, and 62.6%, respectively. Median TTT was 1.7 months (range 0.2-18.1). Using a cut-off of 1.5 months to compare patients receiving upfront vs delayed treatment, there was no difference in LC (p=0.5644), FFP (p=0.1976) or OS (p=0.3018) between the two groups. Of 1038 pts with histologic diagnosis, TTT was associated with OS but not LC or FFP for SqC pts (p=0.0422), and with no AC outcomes. An association of TTT with FFP for pts aged 70-79 (p=0.0302) was seen but otherwise no significant differences were noted in TTT outcomes for pts stratified by T stage, age in decades or KPS. Pt and tumor characteristics were balanced between cut-off cohorts. <h3>Conclusion</h3> Although TTT per se was not associated with altered lung SBRT outcomes in this cohort of nearly 1600 early-stage inoperable lung cancer pts, increasing TTT was found to have a negative association with OS for SqC pts on subset analysis. Previous studies have suggested impaired LC for SqC with SBRT although this was not seen in either of the TTT cut-off cohorts. Further work is warranted to determine how TTT may affect SBRT outcomes in the SqC population.

Development of a Support Vector Machine-Based Tool for Survival Prediction after Stereotactic Body Radiotherapy for Liver Metastases Using Multi-Institutional Data

<h3>Purpose/Objective(s)</h3> Stereotactic body radiotherapy (SBRT) has been increasingly used as well-tolerated, effective treatment for metastatic liver lesions. Machine learning can predict outcomes and aid in developing treatment regimens; however, few studies have attempted to predict liver SBRT outcomes and most have been limited to a single institution. Support vector machine (SVM) algorithms can address complex classification by mapping data into multi-dimensional space. This study aims to develop an SVM-based model to predict survival after SBRT for liver metastases using multi-institutional data. <h3>Materials/Methods</h3> The Comprehensive Liver Pooled SBRT Outcomes (CaLiPSO) is an international consortium of four high-volume SBRT academic centers. Patients who received SBRT for liver metastases were identified from the CaLiPSO database; baseline demographic, clinical, and dosimetric data were collected. Outcomes of interest were overall survival at 12, 18, and 24 months (12mo-OS, 18mo-OS, and 24mo-OS). We investigated a SVM algorithm using a Gaussian kernel and 10-fold cross-validation schema. Performance was measured by accuracy defined as the ratio of correct classifications to samples and by computing the area under the receiving operator characteristic curve (AUC of ROC). Training was performed using a programming environment. <h3>Results</h3> A total of 132 patients with metastatic liver lesions treated with SBRT were included in this study, 77 females (58.3%) and 55 males (41.7%) with median age of 65 years (range 27-88). The median 2-Gy Equivalent Dose (EQD2) was 60 Gy. At the time of SBRT, 62 patients (47.0%) had extrahepatic disease and 70 (53.0%) did not. The number of patients alive at 12, 18, and 24 months were 64 (48.5%), 52 (39.4%), and 41 (31.1%), respectively. Patients were randomly divided into training (n=92) and testing (n=40) sets. Predictive factors included in the SVM were age, EQD2, planning target volume (PTV), and percentage of normal liver volume. Training set AUCs were above 0.95; results for the testing set are listed in Table 1. Performance at 18 and 24 months had AUC of 0.74 and 0.68, respectively, and was improved compared to at 12 months. <h3>Conclusion</h3> Using clinical and dosimetric variables, promising results were obtained for accurate prediction of liver SBRT outcomes. To our knowledge, this is the first SVM-based tool for SBRT outcome prediction in liver metastases validated using international, multi-institutional data for over 100 patients. This tool can help improve care and facilitate appropriate treatment escalation; it can be implemented online for the radiation oncology community as it uses commonly collected data and is easy to compute. The tool can be further refined and validated with larger cohorts in prospective trials.

Efficacy of Stereotactic Body Radiation Therapy for Hepatocellular Carcinoma by Underlying Liver Disease Etiology

<h3>Purpose/Objective(s)</h3> The use of stereotactic body radiation therapy (SBRT) for hepatocellular carcinoma (HCC) has been steadily increasing. Recently, it was reported that patients with HCC have a differential response to immune-checkpoint inhibitor based on the background liver disease etiology. Whether outcomes of SBRT are affected by underlying liver disease etiology is currently unknown. We therefore reviewed outcomes of SBRT with special focus on tumor size, BED, and underlying liver disease etiology. <h3>Materials/Methods</h3> This study is a retrospective review of HCC patients treated with SBRT at one institution between 2009 and 2021. Patients with tumor thrombus or extrahepatic disease were excluded. Kaplan-Meier curves and Cox regression models were used to describe freedom from local progression (FFLP) and overall survival (OS) rates and examine potential prognostic factors. <h3>Results</h3> One-hundred and sixty-four patients met study entry criteria. Median gross tumor volume (GTV) size was 9.3 cc (range 0.3 to 762.4 cc). 67% of patients had a history of hepatitis C, and 9% had a history of hepatitis B. 71% of patients received our institutional standard SBRT dose of 50 Gy in 5 fractions (biological effective dose [BED] 100 Gy). Other patients received lower doses ranging from 30 to 47.5 Gy in three to five fractions (BED range 48 to 93 Gy) if necessary to preserve normal liver tissue. Median follow-up time was 43 months (interquartile range [IQR] 36 to 52 months). Seventeen in-field failures and 67 deaths have occurred. 3- and 5-year FFLP rates were 84% and 75%, and 3- and 5-year OS rates were 65% and 48%, respectively. History of hepatitis C was associated with better FFLP (HR=0.36 (95% CI:0.14, 0.94), p=0.038). Treatment with 50 Gy was associated with better FFLP compared to treatment with lower doses for patients with hepatitis C (HR=0.15 (95%CI: 0.04, 0.63), p=0.01) but not for other patients (HR=3.1 (95%CI: 0.38, 24.7), p=0.29). <h3>Conclusion</h3> SBRT for HCC yields excellent local control, particularly for patients with hepatitis C. In hepatitis C patients, dose escalation beyond a BED of 100Gy may be more important for local control than in non-hepatitis C patients. More studies are necessary to better understand if HCC etiology should be considered when planning SBRT.

Mature Outcomes of Stereotactic Body Radiotherapy for Spinal Metastases with 30 Gy in 4 Fractions

<h3>Purpose/Objective(s)</h3> At our institution, 30 Gy in 4 spine stereotactic body radiotherapy (SBRT) fractions is typically delivered for larger volume when multiple segments are included in the treatment volume and/or for the retreatment of spinal metastases. We report MRI-based local failure (LF) and vertebral compression fracture (VCF) rates for patients (pts) treated with 30 Gy/4Fx of spine SBRT. <h3>Materials/Methods</h3> A retrospective analysis of all pts with spine metastases treated with 30 Gy/4Fx from 2010 to 2021 from an institutional registry was performed. Demographic, clinical, dosimetric, and radiological data were summarized, and the primary endpoint was the MRI-based LF rate. Secondary endpoints included the incidence of VCF and overall survival (OS). Kaplan Meier was used to calculate LF and VCF per segment and OS per patient. <h3>Results</h3> Were included 116 pts with 245 treated segments in this analysis. The median number of consecutive segments in the treatment volume was 3 (1-7), and the median clinical target volume (CTV) was 126 cc (range, 10-863). Kidney (25%), lung (20%), breast (19%), prostate (19%), and colon (10%) cancer were the most common primary histologic types. 38% of pts had oligometastatic disease and 24% spine metastases only. 15% (17/116) of the patients were treated with postoperative SBRT. 31% of segments were re-irradiated for conventional palliative radiation, and 26% prior SBRT, failures. 25% of segments had a baseline VCF, 46% epidural disease, and 53% paraspinal tumor extension. The median follow-up per patient was 18.5 (range, 0.1-61) and per segment 10.7 mos (range, 0.1-59). The LF rates at 12 and 24 mos were 10.7% (95% CI 7.1-15.2) and 16% (95% CI 11.5-21.2), and for VCF were 7.3% (95% CI 4.4-11.2) and 11.2% (95% CI 7.5-15.8), respectively. 60% of failures had an epidural, and 23% a paraspinal, component. Age <68y (HR=0.43, 95% CI 0.19-0.95, p=0.038), volume of CTV <72cc (HR=0.09, 95% CI 0.01-0.70, p=0.021), and prior surgical stabilization (HR=0.25, 95% CI 0.07-0.81, p=0.021) were protective predictors for VCF on multivariable analyses (MVA). In particular, the VCF rate at 24 mos was 1.8% for pts with CTV volume <72 vs 14.6% for ≥72cc. Median OS was 20.3 mos (95% CI 14.8-27.1). Low grade or no epidural disease (HR=0.42, 95% CI 0.21-0.84, p=0.014), paraspinal disease (HR=3.07, 95% CI 1.68-5.62, p<0.001) and kidney primary cancer (HR=2.43, 95% CI 1.08-5.44, p=0.031) were predictors for OS on MVA, with a trend for oligometastatic disease (HR=0.56, 95% CI 0.31-1.02, p=0.059). No radiation-induced myelopathy was observed. <h3>Conclusion</h3> This first report for 30 Gy/4Fx as a novel fractionation for spine SBRT suggests high rates of local control and a low rate of VCF, particularly for those target volumes with a CTV<72 cc. However, our rate of VCF in very large treatment volumes (≥72cc) is comparable to the SBRT-induced VCF literature, where optimal management remains an active area of investigation.

Clinical Outcomes of Prostate SBRT Using Non-Adaptive MR-Guided Radiotherapy (MRgRT)

<h3>Purpose/Objective(s)</h3> Stereotactic body radiation therapy (SBRT) is widely used for localized prostate cancer and implementation of MR-guided radiotherapy (MRgRT) has the advantage of smaller target margins and improved sparing of organs at risk. Here we evaluate outcomes and time required to treat using non-adaptive MRgRT for prostate SBRT at our institution. <h3>Materials/Methods</h3> From 9/2019 to 10/2021, 77 consecutive patients were treated with MRgRT prostate SBRT. Patients included low (4%), favorable intermediate (40%), unfavorable intermediate (49%) and high risk (7%). Short-term ADT was used in 32% of patients. Our clinical pathway allowed maximum prostate gland volume of 60cc. Target volumes included prostate gland and proximal seminal vesicles with an isotropic 3mm margin. Treatment was prescribed to 36.25 Gy in 5 fractions every other day with urethral sparing to maximum dose of 35 Gy. SpaceOAR gel was used in 17% of patients Time on the Linac was recorded as beam on time (BOT) plus total treatment time (TTT) including gating. Analyzed outcomes included PSA response and patient reported outcomes scored by the American Urological Association (AUA) questionnaire and toxicity per CTCAE v5. Repeated-measure analysis and Bonferroni correction were used to test changes in PSA and toxicity. <h3>Results</h3> Median follow up was 9.5 months (range 1.1 – 23.1). Median pre-treatment PSA was 6.5 (range 2.2 – 19.6) and median AUA score was 6 (1 – 25) with a median prostate size of 32.6 cc (range 17 – 70). At first follow up, median change in PSA was -5.23 ng/mL (Delta range +0.02– -19.3ng/ml) with a median AUA of 10 (range 1 – 26). At second follow up, median change in PSA was -6.33 ng/mL (range +1.48– -19.31ng/mL) and median AUA of 7 (range 0 – 33). At third follow up, median change in PSA was -6.09ng/mL (range -1.84 – -14.9ng/mL) and median AUA was 6.5 (1 – 25). There was a significant decrease in PSA between pre-treatment and first through fourth follow up (p=0.003). The greatest difference was between pretreatment PSA and PSA at 4^thfollow-up (decrease in PSA by 5.9 ng/ml, p<.001). Toxicity as measured by CTCAE v5 decreased from 53% at first follow up to 23% at second follow up and 1% at third follow up. Common toxicities included grade 2 urethritis, tenesmus and one grade 3 proctitis. No grade ≥4 toxicity was seen. Our MR-Linac underwent an upgrade in 11/2020 allowing for faster treatment times. For patients treated prior to the upgrade, mean BOT was 4.89 min with a TTT of 12.50 min whereas for those treated after mean BOT was 4.52 min with a TTT of 10.68 min. <h3>Conclusion</h3> A benefit of MRgRT is the potential for treatment adaptation, however it comes at the cost of increased resource utilization and reduced clinical efficiency. Our experience with non-adaptive MRgRT prostate SBRT maintains clinical efficiency as well as efficacy. Taken together these results suggest a non-adaptive approach may allow more patients to access an effective and safe treatment, while also maximizing resource utilization.

Treatment of Thymic Oligometastastic or Oligoprogressive Lesions with Hypofractionated Radiation Therapy or Stereotactic Body Radiation Therapy

<h3>Purpose/Objective(s)</h3> Recent large clinical trials have demonstrated an improvement in local failure-free survival (LFFS) and progression free survival (PFS) with hypofractionated radiation therapy (HFRT) and stereotactic body radiation therapy (SBRT) in select patients with oligometastatic (OM) and oligoprogressive (OP) disease. However, little is known about the outcomes of HFRT and SBRT in patients with OM or OP disease from thymic malignancies. Therefore, the purpose of this analysis was to characterize the outcomes of such patients treated at our institution. <h3>Materials/Methods</h3> We retrospectively reviewed patients with OM or OP thymic malignancies treated with HFRT or SBRT between 2009-2021. We defined OM as 5 or fewer sites of metastatic disease at the time of RT and OP as 5 or fewer sites of metastatic disease increasing in radiological size. Patients treated with 20 or fewer fractions of radiation were included. Survival outcomes were defined from the end of RT. Analyses were done using the <i>lifelines</i> module in Python. <h3>Results</h3> We analyzed 48 patients treated to 81 lesions. The median age was 54 years old (range: 24-82 years), 63% were male and 79% were white. Patients had thymoma (54%), thymic carcinoma (38%), or atypical thymic carcinoid (8%). At the time of initial diagnosis, patients were stage I-II (21%), III (12.5%), IVA (23%) or IVB (42%). The majority of patients (65%) received systemic therapy prior to radiation therapy. Of the 81 lesions treated, 67 (83%) were OM lesions and 14 (17%) were polymetastatic, but OP lesions. Treatment sites included bone (37%), pleura (25%), lymph nodes (20%), lung (10%), brain (5%) and other (4%). Most patients were treated in 3 fractions (N=31; 8-10 Gy x 3 fractions), 5 fractions (N=28; 5-7 Gy x 5 fractions (N=20) or 8-10 Gy x 5 fractions (N=8)), or 15 fractions (N=11; 2.5-4 Gy x 15 fractions). The median biological effective dose (BED) was 51.3 Gy. Median follow up was 16 months. The 2-year/5-year rates of LFFS and PFS were 83%/76% and 32%/17%, respectively. The 2-year/5-year/10-year rates of overall survival (OS) were 92%/80%/61%. Patients with thymic carcinoma or atypical carcinoid had similar LFFS vs. those with thymoma (2-year LFFS: 85% vs. 82%, p=0.31), but they had shorter PFS (2-year PFS: 5% vs. 39%, p=0.01), and OS was not significantly different (2-year OS: 86% vs. 96%, p=0.25). Patients (N=14 patients treated to 19 lesions) treated with a BED > 60 Gy did not experience any local failure at 2 years (2-yr LFFS=100%). <h3>Conclusion</h3> Patients with OM or OP thymic malignancies treated with HFRT or SBRT had high rates of LFFS, PFS and OS. Despite having a more aggressive disease, patients with thymic carcinoma still experienced favorable LFFS with HFRT or SBRT. Patients treated with regimens with BED greater than 60 Gy had excellent LFFS. These results suggest that with long OS and PFS times, consideration should be given to SBRT/HFRT regimens to maximize local control in these patients with favorable prognoses.

Outcomes of SBRT for Symptomatic Benign Tumors of the Spine

<h3>Purpose/Objective(s)</h3> Benign spinal tumors (BSTs) are rare, present across the age spectrum, and may be associated with significant neurologic morbidity. While conservative medical management may be sufficient, many patients experience progression requiring escalated interventions, including surgery. Stereotactic body radiotherapy (SBRT) may be an additional effective management approach for BSTs in the upfront or adjuvant setting. We report our institutional experience of SBRT in management of BSTs. <h3>Materials/Methods</h3> Patients with symptomatic BSTs treated at a single institution with SBRT from 2010-2020 were retrospectively reviewed. Treatment outcomes including symptom and radiographic response were recorded from the electronic health record and presented with descriptive statistics and analyzed by chi-square and univariate logistic regression. <h3>Results</h3> In total, 31 patients with 36 symptomatic BSTs receiving SBRT were identified. Median age at presentation was 57 (IQR: 43-63). Pain was the primary symptom at presentation (92%), followed by paresthesias (28%) and weakness (19%). Histologies were schwannoma (39%), meningioma (33%), hemangioma (22%), and other (6%). Treated spine levels were cervical (44%), thoracic (36%), lumbosacral (19%). 47% of patients had prior surgery at the treated site. Median SBRT prescription dose was 25 Gy (range: 18-40 Gy in 3-5 fractions) treated on consecutive days. Median PTV was 6.0 cc (IQR: 3.5-19.4 cc). Median thecal sac max (0.03 cc) dose was 26.2 Gy (range 0.4-30.2). Interval imaging cadence following treatment was q3-6 months. Median radiographic f/u was 28 months (IQR 9-60). 58% of patients reported durable symptom improvements. 44% of patients experienced acute toxicity from treatment including fatigue, esophagitis, regional pain flare (all grade≤2). One patient developed symptomatic radiation-induced mid-thoracic level myelitis at 6 mo following SBRT with neurologic improvement following protracted (>3 mo) steroid administration with taper. 50% of patients demonstrated radiographic response at last follow-up while 3% showed progression and 47% remained stable. There was no significant association between treatment response or acute/late toxicity and lesion location, dose, or prior surgery. <h3>Conclusion</h3> SBRT for BST, as definitive therapy or for salvage following surgery, was largely effective and safe, with limited high-grade toxicity. Most patients demonstrated symptomatic and/or radiographic response following spine-lesion directed SBRT.

Evaluation of treatment results of stereotactic body radiotherapy for spinal metastases: A single center experience

Aim: To assess oncological outcomes and adverse events of patients receiving single or multi-fraction stereotactic body radiotherapy (SBRT) for spine metastases. &#x0D; Material and Method: Patients with any pathologically proven solid tumor histology who had SBRT to the spine for recurrent or metastatic disease between the years 2010 and 2021 at our department were identified from institutional database. Patient, tumor and treatment characteristics, and follow-up medical records were retrospectively reviewed. Local control (LC) and overall survival (OS) rates were calculated, and adverse events were evaluated.&#x0D; Results: A total of 47 patients were treated to 50 spine metastases. Median age was 53 years for all patients. Histologies included breast cancer (45%), non-small cell lung cancer (NSCLC; 21%), prostate cancer (15%) and other types (19%). Median follow-up was 16 months for all patients. Of 47 patients, six (13%) developed local failure and 15 (32%) died without local failure. One and two-year actuarial LC rates were 90.1% and 83.6%, respectively. One and two-year OS rates were 75.1% and 62.7%, respectively. Twenty-two (47%) patients had pain before SBRT. Fifteen (68%) of them had complete or partial pain response at 3 months after SBRT. Vertebral compression fracture, which was grade 1 in severity according to the Common Terminology Criteria for Adverse Events (CTCAE [v.4.03]), was observed in only one (2%) patient and it occurred 46 months after SBRT. No cases of treatment-related radiation myelopathy or any≥grade 3 RT induced acute or late toxicities occurred. &#x0D; Conclusion: This study supports that SBRT to the spine results in high LC without any significant toxicity. The results of ongoing phase 3 trials will highlight whether this high LC benefit reflects to survival in oligometastatic disease.

Stereotactic Radiotherapy for Adrenal Metastases: A Multi-Institutional Review of Patient Characteristics and Outcomes – Turkish Society for Radiation Oncology SBRT Group Study (Trod SBRT 10-004)

Introduction: This study aimed to report the outcomes of stereotactic body radiotherapy (SBRT) for adrenal metastasis in a retrospective multi-institutional cohort. Methods: The outcomes of 124 patients with 146 adrenal metastases who underwent SBRT within 11 years (2008–2019) were retrospectively evaluated. Survival outcomes were analyzed by the Kaplan-Meier method. Patient, tumor, and treatment characteristics and their effects on survival, local control (LC), and toxicity outcomes were analyzed by log-rank and multivariate Cox regression methods. Results: The median age was 60 years. The most frequent primary tumor site was the lung, followed by the gastrointestinal system and breast. The adrenal gland was the only metastatic site in 49 (40%) patients. Median biologically effective dose (BED)10 was 61 Gy. The overall LC rate was 83%, and it was positively correlated with the BED10 and fraction dose. The 1- and 2-year local recurrence-free survival, overall survival (OS), and progression-free survival (PFS) rate was 79% and 69%, 83% and 60%, and 31% and 12%, respectively. OS significantly improved with non-lung cancer and <4-cm lesion and PFS with a fraction dose ≥8 Gy, BED10 >65 Gy, and an isolated adrenal metastasis. Fourteen patients reported an acute toxicity, and late toxicity was observed in 3 patients, including one grade 5. Conclusion: A satisfactory LC rate was achieved for adrenal metastasis via SBRT. A higher BED10 and fraction dose were positive prognostic factors for tumor control. However, the main problem is DM in these patients, and systemic treatment options are needed to be improved.

EP02.02-010 Histology Impacts Time-to-Treatment on Lung SBRT Outcomes

Time-to-treatment (TTT) is considered an indicator of quality care that has been postulated to affect lung cancer outcomes. The process by which an early stage medically inoperable lung cancer patient (pt) is deemed appropriate for lung stereotactic body radiation therapy (SBRT) typically involves a multi-disciplinary assessment over extended time. This study analyzed a large single institution registry to explore the impact of TTT on SBRT outcomes.

34: Outcomes of Stereotactic Body Radiotherapy for Metastases to the Head and Neck

34: Outcomes of Stereotactic Body Radiotherapy for Metastases to the Head and Neck

Stereotactic Body Radiotherapy for Renal Cell Carcinoma: Oncological and Renal Function Outcomes

AimsTo evaluate oncological and renal function outcomes of stereotactic body radiotherapy (SBRT) for medically inoperable patients with localised renal cell carcinoma. Materials and methodsConsecutive patients treated with curative intent SBRT (30–45 Gy in five fractions or 42 Gy in three fractions) were included. Data on local control (Response Evaluation Criteria in Solid Tumors [RECIST] v1.1), distant metastasis, impact on estimated glomerular filtration rate (eGFR) and proportional ipsilateral and contralateral renal functions (measured through renal scans) were collected. Univariate and multivariable analyses were conducted to determine association of variables with oncological and renal function outcomes. ResultsSeventy-four patients were analysed. The median follow-up was 27.8 months (interquartile range 17.6–41.7). Fifty-seven per cent had tumours ≥ T1b. One-, 2- and 4-year cumulative incidence of local failure was 5.85, 7.77 and 7.77%, respectively. The cumulative incidence of distant metastasis at 2 years was 4.24%. On multivariable analysis, a lower planning target volume (PTV) mean dose (P = 0.019) and a larger PTV (P = 0.005) were significantly associated with the risk of developing local failure. A lower PTV maximum dose (P = 0.039) was significantly associated with the risk of developing distant metastasis. The median change in global eGFR (ml/min) from pre-SBRT levels was –7.0 (interquartile range –14.5 to –1.0) at 1 year and –11.5 (interquartile range –19.5 to –4.0) at 2 years. The proportion of ipsilateral (differential) renal function decreased over time from 47% of overall renal function pre-SBRT to 36% at 2 years, whereas the proportion of contralateral renal function correspondingly improved. On multivariable analysis, a higher volume of uninvolved renal cortex (P < 0.0001) was significantly associated with a smaller decrease in eGFR over time. ConclusionIn this large institutional cohort, oncological outcomes of renal cell carcinoma treated with SBRT were favourable and a longitudinal decline in renal function in the ipsilateral kidney and compensatory increase in the contralateral kidney were observed. Clinical and dosimetric factors were significantly associated with oncological and renal function outcomes.

Spine Stereotactic Body Radiotherapy to Three or More Contiguous Vertebral Levels.

BackgroundWith survival improving in many metastatic malignancies, spine metastases have increasingly become a source of significant morbidity; achieving durable local control (LC) is critical. Stereotactic body radiotherapy (SBRT) may offer improved LC and/or symptom palliation. However, due to setup concerns, SBRT is infrequently offered to patients with ≥3 contiguous involved levels. Because data are limited, we sought to evaluate the feasibility, toxicity, and cancer control outcomes of spine SBRT delivered to ≥3 contiguous levels.MethodsWe retrospectively identified all SBRT courses delivered between 2013 and 2019 at a tertiary care institution for postoperative or intact spine metastases. Radiotherapy was delivered to 14–35 Gy in 1–5 fractions. Patients were stratified by whether they received SBRT to 1–2 or ≥3 contiguous levels. The primary endpoint was 1-year LC and was compared between groups. Factors associated with increased likelihood of local failure (LF) were explored. Acute and chronic toxicity was assessed. In-depth dosimetric data were collected.ResultsOverall, 165 patients with 194 SBRT courses were identified [54% were men, median age was 61 years, 93% had Karnofsky Performance Status (KPS) ≥70, and median follow-up was 15 months]. One hundred thirteen patients (68%) received treatment to 1–2 and 52 to 3–7 (32%) levels. The 1-year LC was 88% (89% for 1–2 levels vs. 84% for ≥3 levels, p = 0.747). On multivariate analysis, uncontrolled systemic disease was associated with inferior LC for patients with ≥3 treated levels. No other demographic, disease, treatment, or dosimetric variables achieved significance. Rates of new/progressive fracture were equivalent (8% vs. 9.5%, p = 0.839). There were no radiation-induced myelopathy or grade 3+ acute or late toxicities in either group. Coverage of ≥95% of the planning target volume with ≥95% prescription dose was similar between groups (96% 1–2 levels vs. 89% ≥3 levels, p = 0.078).ConclusionsFor patients with ≥3 contiguous involved levels, spine SBRT is feasible and may offer excellent LC without significant toxicity. Prospective evaluation is warranted.

Stereotactic body radiotherapy boost in patients with cervical cancer

Our aim was to evaluate the oncological outcomes of stereotactic body radiotherapy (SBRT) boost in patients with cervical cancer. The data of 21 patients who received SBRT boost after definitive radiotherapy (RT) or chemoradiotherapy (CRT) between March 2012 and April 2019 were retrospectively evaluated. External beam radiotherapy (EBRT) was applied to patients with a total dose of 50.4 Gy in 28 fractions. Kaplan–Meier method was used for survival analysis (IBM SPSS 23 software) and p < .05 value was considered significant. After definitive RT or CRT, there was a complete response in 9 (43%) patients, partial response in 11 (52%) patients and stable disease in 1 (5%) patient. The median follow-up period was 28 months (range, 7.5–88 months). Two-years cancer-specific survival rate was 80%. While 2-year LC rate was 75% in patients with residual tumour size <4 cm, it was 50% when there was ≥4 cm residual tumour after definitive CRT (p = .1). The treatment was well-tolerated and no acute or late toxicity was observed. Although brachytherapy (BRT) is an essential part of the treatment in locally advanced cervical cancer, SBRT may be used in patients with small residual disease who are not candidate for BRT. IMPACT STATEMENT Cervical cancer is one of the most common cancers in the world, and external beam radiotherapy (EBRT) and brachytherapy (BRT) are the main treatment options. However, in rare cases where BRT is not feasible, it has been questioned whether stereotactic body radiotherapy (SBRT) as an alternative to BRT. What is already known on this subject? Nowadays, BRT still appears to be the gold standard treatment. However, studies with a small number of patients and short follow-up periods in the literature show that SBRT can be a good alternative in cases where BRT cannot be performed. What do the results of this study add? Our study is one of the series with the largest number of patients in the literature and with the longest follow-up period. In this area where there is no prospective study, we think that retrospective data with high patient numbers are enlightening. What are the implications of these findings for clinical practice and/or further research? Our study shows that SBRT is an alternative option in cases with small residual disease where BRT cannot be applied, and it provides a basis for a prospective randomised study.

Applying Artificial Neural Networks to Develop a Decision Support Tool for Tis-4N0M0 Non-Small-Cell Lung Cancer Treated With Stereotactic Body Radiotherapy.

PURPOSEClear evidence indicating whether surgery or stereotactic body radiation therapy (SBRT) is best for non–small-cell lung cancer (NSCLC) is lacking. SBRT has many advantages. We used artificial neural networks (NNs) to predict treatment outcomes for patients with NSCLC receiving SBRT, aiming to aid in decision making.PATIENTS AND METHODSAmong consecutive patients receiving SBRT between 2005 and 2019 in our institution, we retrospectively identified those with Tis–T4N0M0 NSCLC. We constructed two NNs for prediction of overall survival (OS) and cancer progression in the first 5 years after SBRT, which were tested using an internal and an external test data set. We performed risk group stratification, wherein 5-year OS and cancer progression were stratified into three groups.RESULTSIn total, 692 patients in our institution and 100 patients randomly chosen in the external institution were enrolled. The NNs resulted in concordance indexes for OS of 0.76 (95% CI, 0.73 to 0.79), 0.68 (95% CI, 0.60 to 0.75), and 0.69 (95% CI, 0.61 to 0.76) and area under the curve for cancer progression of 0.80 (95% CI, 0.75 to 0.84), 0.72 (95% CI, 0.60 to 0.83), and 0.70 (95% CI, 0.57 to 0.81) in the training, internal test, and external test data sets, respectively. The survival and cumulative incidence curves were significantly stratified. NNs selected low-risk cancer progression groups of 5.6%, 6.9%, and 7.0% in the training, internal test, and external test data sets, respectively, suggesting that 48% of patients with peripheral Tis–4N0M0 NSCLC can be at low-risk for cancer progression.CONCLUSIONPredictions of SBRT outcomes using NNs were useful for Tis–4N0M0 NSCLC. Our results are anticipated to open new avenues for NN predictions and provide decision-making guidance for patients and physicians.

Stereotactic ablative body radiotherapy of ventricular tachycardia. Single italian centre experience

Abstract Funding Acknowledgements Type of funding sources: None. Background Ventricular tachycardia (VT) is a life-threatening condition. Usual management of VT is based on anti-arrhythmic drugs or catheter ablation. In this scenario, stereotactic body radiation therapy (SBRT) is arising as an attractive non-invasive alternative for the treatment of VT in some patients (pts). Purpose The aim of this study was to assess safety, feasibility and outcomes of SBRT in fragile pts admitted in our centre for VT storms. Methods Pts with implantable cardioverter-defibrillator (ICD), presenting with VT storms and not responsive to drugs or suitable for catheter ablation were enrolled for SBRT. All pts underwent a computed tomography (CT) and an 18F-fluorodeoxyglucose positron emission (FDG PET)-CT scan in order to detect a possible area of scar responsible of the VT. All pts had also an electrophysiological study and ventricular programmed stimulation inducing clinical VT while wearing a multi-electrodes ECG vest. Merging the CT scan imagines and the VT 3D reconstruction, we identified the possible circuit of the VT and its exit sites. Treatment planning was performed for a total dose of 21-25 Gy delivered in a single session. For the first year, follow-up (FU) were scheduled every 3 months since the SBRT treatment. Toxicity was prospectively assessed. Results From January 2020 to March 2021, we treated 6 (5 males) pts. Mean age was 78±4. NYHA class was II for 3 pts, 2 were class III and only one pts was class IV. Four pts had an ischaemic heart disease background, two had dilated cardiomyopathy (DCM). Mean ejection fraction (EF) was 31±6%. The mean FU was 17 months, with the longest of 23 months. Of these 6 pts, only one died because of end stage heart failure, no VT/VF were recorded on his ICD. This was the pts with DCM and class NYHA IV at the time of procedure. Of the 5 pts remaining, 2/5 reported new therapies delivered by their ICDs. One pts had a single ICD shock during acute urine tract infection and sepsis at one month since SBRT. ICD interrogation documented inappropriate shock on fast conducted atrial fibrillation. No VTs have been recorded after 7 months. The other pts was admitted after 5 months since SBRT. The ICD showed appropriate therapies on VTs. This pts had the biggest scar volume compared to the others (anterior wall of the left ventricle with aneurysmatic apex). On the other 3 pts, no VTs were recorded by ICDs. Of these 3 pts, interestingly, 2 had class NYHA III and the mean EF 28.6±3%. The overall outcome with no appropriate ICD shocks due to VTs is above 70%. No radiotherapy toxicity was documented. Conclusion To the best of our knowledge this is one of the biggest groups of pts treated with this technology and the longest FU so far, of a single centre in Italy. SBRT seems to be a safe and feasible approach to treat fragile pts with VTs when not suitable for standard catheter ablation or responsive to medications. It also shows a good outcome even in pts with more advanced heart failure.

MP55-16 FOCAL CRYOTHERAPY AND STEREOTACTIC BODY RADIOTHERAPY HAVE SIMILAR ONCOLOGIC AND FUNCTIONAL OUTCOMES IN TREATMENT OF LOW-TO-INTERMEDIATE UNILOBE PROSTATE CANCER

You have accessJournal of UrologyCME1 May 2022MP55-16 FOCAL CRYOTHERAPY AND STEREOTACTIC BODY RADIOTHERAPY HAVE SIMILAR ONCOLOGIC AND FUNCTIONAL OUTCOMES IN TREATMENT OF LOW-TO-INTERMEDIATE UNILOBE PROSTATE CANCER Ashley Monaco, Jessica Sommer, Chinyere Okpara, Jonathan Haas, Anthony Corcoran, and Aaron Katz Ashley MonacoAshley Monaco More articles by this author , Jessica SommerJessica Sommer More articles by this author , Chinyere OkparaChinyere Okpara More articles by this author , Jonathan HaasJonathan Haas More articles by this author , Anthony CorcoranAnthony Corcoran More articles by this author , and Aaron KatzAaron Katz More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002634.16AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Minimal invasive treatment options such as focal cryotherapy (FC) and stereotactic body radiotherapy (SBRT) continue to evolve and grow in popularity. Comparative outcome data for these treatment options are sparse. This study compares oncologic and functional outcomes as well as complications following FC or SBRT for low-to-intermediate risk unilobe prostate cancer (PCa). METHODS: An IRB-approved database was reviewed for patients who underwent FC or SBRT for low-to-intermediate risk PCa as defined by D’Amico criteria. Patients with >1 year of follow-up, had prior PCa treatment, or PCa that was bilateral were excluded from this study. TF was defined as salvage treatment, a positive biopsy Gleason group (GG) of 2 or greater on post-treatment biopsy, or PCa metastasis. Functional outcomes were based on 2-year post treatment patient reported EPIC urinary, sexual, and bowel function surveys. Complications were categorized with the Clavien Dindo classification (CD). Descriptive statistics, univariate analyses, and Kaplan Meier curve were used to compare outcomes of SBRT and FC. P <0.05 was significant. RESULTS: 68 FC and 51 SBRT patients with a median age of 68 years (48-86) and a median follow-up time of 82 (14-135) months were included in this analysis. There was no difference in PCa risk (p=0.473), GG (p=0.2), or PSA (p=0.8) among the two cohorts at baseline. There was no difference between patients who experienced TF (19% vs. 18%; p=0.8; log-rank p=0.7), underwent salvage treatment (18% vs 18%; p=1.0), or had metastasis (2.9% vs. 9.8%; p=0.1) among FC and SBRT patients, respectively. At a minimum of 2-years post-treatment, urinary function (94 vs. 89; p=0.3), bowel function (96 vs. 96; p=0.4), and sexual function (50 vs. 32; p=0.6) were relatively similar among the FC and SBRT patients, respectively. 13 (19%) FC and 10 (20%) SBRT experienced treatment related complications (p=0.8) of which 4 (5.9%) FC and 6 (12%) were CD 1, 7 (10%) FC and 4 (7.8%) SBRT were CD 2, and 2 (2.9%) FC were CD 3A. CONCLUSIONS: Both FC and SBRT are associated with similar, excellent oncologic and functional outcomes 7-years following treatment. These results underscore the utility of FC and SBRT for management of unilobe low-to-intermediate risk PCa. Source of Funding: Department of Urology, NYU Langone Hospital – Long Island © 2022 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 207Issue Supplement 5May 2022Page: e944 Advertisement Copyright & Permissions© 2022 by American Urological Association Education and Research, Inc.MetricsAuthor Information Ashley Monaco More articles by this author Jessica Sommer More articles by this author Chinyere Okpara More articles by this author Jonathan Haas More articles by this author Anthony Corcoran More articles by this author Aaron Katz More articles by this author Expand All Advertisement PDF DownloadLoading ...

Screening of Prognostic Biomarkers for Stereotactic Body Radiation Therapy in Primary Liver Cancer.

ObjectiveSo far there are still no effective immediate-early markers for assessing the efficacy of Stereotactic Body Radiation Therapy (SBRT). To find effective biomarkers for accurate assessment of the efficacy of SBRT in patients with primary liver cancer, we conducted this study including retrospective part and prospective part.Material and Methods589 patients with primary liver cancer were included at Ruikang Hospital affiliated to Guangxi Medical University from January 2012 to December 2018. Follow-up was conducted, clinical information and a total of 17 patients with 51 blood samples (before SBRT, before discharge and 2 months after SBRT) were collected. mRNAs profiles on 2 patients with 6 blood samples were detected by high-throughput sequencing, followed by qPCR verification on 15 patients with 45 blood samples.ResultsThe commonly used serum biomarkers such as AFP, CEA, and CA125 shown low prognostic value in distinguishing survival group and death group, indicated by low AUC (less than .7) and Youden indexes (less than .5). Based on high-throughput sequencing of test group and qPCR detection of another verification group, we found 16 up-regulated and 12 downregulated genes after SBRT. Among them, ADIPOR1 and EPB42 showed significantly different between effective and ineffective group after SBRT, ROC suggested that based on the optimal threshold of .5838, ADIPOR1 shown a sensitivity of 100% and a specificity of 83.33% to distinguish effective from ineffective group. And EPB42 had a sensitivity of 75% and a specificity of 100% at the optimal threshold of 1.3817. In addition, GSEA showed that high expression of ADIPOR1 was mainly related to Mismatch repair, Circadian rhythm, Protein processing in endoplasmic reticulum, DNA replication, and Fanconi anemia pathways.ConclusionADIPOR1 in whole blood is a promising candidate to act as prognostic biomarker for predication of SBRT outcomes in primary liver cancer patients.

How to Improve SBRT Outcomes in NSCLC: From Pre-Clinical Modeling to Successful Clinical Translation.

Simple SummaryDespite major research and clinical efforts, lung cancer remains the leading cause of cancer-related death. Stereotactic body radiotherapy (SBRT) has emerged as a major treatment modality for lung cancer in the last decade. Additional research is needed to elucidate underlying mechanisms of resistance and to develop improved therapeutic strategies. Clinical progress relies on accurate preclinical modelling of human disease in order to yield clinically meaningful results; however, successful translation of pre-clinical research is still lagging behind. In this review, we summarize the major clinical developments of radiation therapy for non-small-cell lung cancer (NSCLC), and we discuss the pre-clinical research models at our disposal, highlighting ongoing translational challenges and future perspectives.Despite major research and clinical efforts, lung cancer remains the leading cause of cancer-related death. While the delivery of conformal radiotherapy and image guidance of stereotactic body radiotherapy (SBRT) have revolutionized the treatment of early-stage non-small-cell lung cancer (NSCLC), additional research is needed to elucidate underlying mechanisms of resistance and identify novel therapeutic combinations. Clinical progress relies on the successful translation of pre-clinical work, which so far has not always yielded expected results. Improved clinical modelling involves characterizing the preclinical models and selecting appropriate experimental designs that faithfully mimic precise clinical scenarios. Here, we review the current role of SBRT and the scope of pre-clinical armamentarium at our disposal to improve successful clinical translation of pre-clinical research in the radiation oncology of NSCLC.