Use Of Stereotactic Body Radiotherapy Research Articles

Multisite stereotactic body radiotherapy for metastatic non-small-cell lung cancer: Delaying the need to start or change systemic therapy?

ObjectivesThe purpose of this study was to review the clinical outcomes following the use of stereotactic body radiotherapy (SBRT) in patients with metastatic non-small-cell lung cancer (NSCLC) from a large academic institution. Materials and methodsMetastatic NSCLC patients treated with extracranial SBRT were identified from an institutional database. Treatment indications were: (1) oligometastases, (2) oligoprogression, and (3) local control of dominant tumors. Endpoints included overall survival (OS), progression-free survival (PFS), time to starting/changing systemic therapy (SCST), and local failure (LF). Univariate and multivariable analyses were performed to look for predictive factors. Results108 patients with 165 tumors were treated. SBRT was delivered for oligometastases in 66 patents, for oligoprogression in 20 patients, and for local control in 22 patients. Median OS and PFS for all patients were 27.3 months and 4.4 months, respectively, with treatment indication being the only predictive factor on multivariable analysis (patients with oligometastases having the highest median OS and PFS of 39.3 months and 7.6 months respectively). Cumulative incidence of SCST was only 21.5% at 1 year after SBRT, with larger tumor size and positivity for EGFR/ALK mutation being predictive of higher rates of SCST on multivariable analysis. LF was 15.6% at 1 year, with larger tumor size and exposure to previous systemic therapy being predictive of higher rates of LF on multivariable analysis. ConclusionPatients treated with SBRT for oligometastases have better OS and PFS than those treated for oligoprogression or for local control of dominant tumors. Use of SBRT may delay the need for SCST. Larger tumors and previous exposure to systemic therapy were predictive of higher rates of LF.

Stereotactic Body Radiotherapy for Oligometastatic Prostate Cancer Detected via Prostate-specific Membrane Antigen Positron Emission Tomography

BackgroundThe management of oligometastatic prostate cancer (PCa) remains controversial, especially following the introduction of prostate-specific membrane antigen (PSMA) positron emission tomography (PET) imaging. ObjectiveTo assess whether stereotactic body radiotherapy (SBRT) provides a potential for cure in a selected group of patients with oligometastatic PCa in the PSMA-PET era. Design, setting, and participantsThis was a prospective, single-centre study of patients with oligometastatic PCa undergoing SBRT from November 2014 to July 2016. We included patients with relapsed PCa receiving SBRT with PSMA-PET-confirmed oligometastases (n=1–3) confined to lymph nodes (LNs) or bone without androgen deprivation therapy. SBRT schedules included 20Gy/1# or 24Gy/2# to bone metastases, and 50Gy/5# or 30Gy/3# to LNs. Outcome measurements and statistical analysisThe primary endpoint was biochemical failure (BF) defined as a prostate-specific antigen (PSA) level of nadir + 0.2 ng/ml following SBRT. Results and limitationsFifty-seven patients were eligible, of whom 50 (88%) had undergone radical prostatectomy. The median time from definitive treatment to SBRT was 5.6 yr. A total of 73 lesions were treated: 44 patients had one metastasis, while 13 had two or three. Thirty-seven patients (65%) had LN-only disease, while 18 (31%) had bone-only metastasis. Median follow up was 16 mo. The median biochemical disease-free survival (bDFS) for the cohort was 11 mo, with 31.9% bDFS at 15 mo. All patients with BF (n=43) underwent a repeat PSMA-PET scan, which revealed no in-field failures. Median bDFS was not affected by prostate-specific antigen (PSA) at diagnosis, Gleason score, time from diagnosis to SBRT, site (bone vs LN), PSA doubling time before SBRT, or number of metastases. Failures were somewhat less common in patients with low PSA before SBRT. Toxicity was rare: no patients developed grade ≥2 late toxicity. ConclusionsSBRT delivered very high rates of local control with minimal toxicity. However, distant recurrences occurred in most patients by 15 mo and did not appear to be predicted by known prognostic factors. Patient summaryIn this report, we looked at outcomes after the use of stereotactic body radiotherapy for patients with prostate cancer spread to one to three lymph nodes or bones as detected by positron emission tomography scans. We demonstrated high rates of control of the treated lesions with low toxicity, but by 15 mo more than two-thirds of patients had developed recurrent cancer outside the treated area.

Long-term outcomes of stereotactic body radiotherapy for low- and intermediate-risk prostate adenocarcinoma: A multi-institutional consortium study.

84 Background: While a growing body of evidence supports the use of stereotactic body radiotherapy (SBRT) for the treatment of low- and intermediate-risk prostate adenocarcinoma (PCa), some trepidation exists regarding its long-term efficacy and safety. Methods: Men with low- and intermediate-risk PCa, as defined per the National Comprehensive Cancer Network guidelines, who were enrolled on various institutional phase II trials of SBRT between 2000-2012 were included in a multi-institutional consortium. Biochemical relapse (BCR) was defined as PSA > “nadir +2” or initiation of androgen deprivation therapy (ADT). Toxicity data were scored according to the CTCAE v 3.0 or Radiation Therapy Oncology Group scoring systems. Results: A total of 1644 men were eligible for analysis, with a median followup of 7.2 years. 297 patients (18.1%) had at least 9 years of followup. Fractionation schemes ranged from 33.50-40 Gy in 4-5 fractions. 892 patients had low-risk disease and 752 had intermediate-risk disease. 59 patients (3.6%) received short-term ADT. 100 patients (6.0%) experienced BCR, and 7 (0.4%) experienced distant metastases. No patients died of PCa. By Kaplan-Meier analysis, 5- and 10-year BCR-free survival rates were 98% and 94% in the low-risk group and 96% and 90% in the intermediate-risk group (p < 0.05 by log-rank test). 5- and 10-year overall survival rates were 93% and 86% in the low-risk group and 95% and 91% in the intermediate-risk group (p > 0.05 by log-rank test). Five patients (0.3%) experienced grade 3 acute genitourinary (GU) toxicities, including urinary retention, hematuria, and frequency. 30 (2%) experienced grade 3 late GU toxicity, including urinary strictures, hematuria, and retention. One late grade 4 GU toxicity (hemorrhagic urethritis) and one late grade 4 gastrointestinal toxicity (fistula-in-ano) were seen. Conclusions: To the best of our knowledge, this is the largest analysis of long-term outcomes following SBRT for PCa. The results indicate that SBRT has an efficacy and toxicity profile that compares favorably to more widespread forms of treatment, such as conventionally-fractionated external beam radiotherapy and brachytherapy.

Modeling the target dose fall-off in IMRT and VMAT planning techniques for cervical SBRT

There has been growing interest in the use of stereotactic body radiotherapy (SBRT) technique for the treatment of cervical cancer. The purpose of this study was to characterize dose distributions as well as model the target dose fall-off for intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) delivery techniques using 6 and 10 MV photon beam energies. Fifteen (n = 15) patients with non-bulky cervical tumors were planned in Pinnacle3 with a Varian Novalis Tx (HD120 MLC) using 6 and 10 MV photons with the following techniques: (1) IMRT with 10 non-coplanar beams (2) dual, coplanar 358° VMAT arcs (4° spacing), and (3) triple, non-coplanar VMAT arcs. Treatment volumes and dose prescriptions were segmented according to University of Texas Southwestern (UTSW) Phase II study. All plans were normalized such that 98% of the planning target volume (PTV) received 28 Gy (4 fractions). For the PTV, the following metrics were evaluated: homogeneity index, conformity index, D2cc, Dmean, Dmax, and dose fall-off parameters. For the organs at risk (OARs), D2cc, D15cc, D0.01cc, V20, V40, V50, V60, and V80 were evaluated for the bladder, bowel, femoral heads, rectum, and sigmoid. Statistical differences were evaluated using a Friedman test with a significance level of 0.05. To model dose fall-off, expanding 2-mm-thick concentric rings were created around the PTV, and doses were recorded. Statistically significant differences (p < 0.05) were noted in the dose fall-off when using 10 MV and VMAT3-arc, as compared with IMRT. VMAT3-arc improved the bladder V40, V50, and V60, and the bowel V20 and V50. All fitted regressions had an R2 ≥ 0.98. For cervical SBRT plans, a VMAT3-arc approach offers a steeper dose fall-off outside of the target volume. Faster dose fall-off was observed in smaller targets as opposed to medium and large targets, denoting that OAR sparing is dependent on target size. These improvements are further pronounced with the use of 10-MV photons.

Local High-Dose Radiotherapy Induces Systemic Immunomodulating Effects of Potential Therapeutic Relevance in Oligometastatic Breast Cancer.

Local irradiation of cancer through radiotherapy can induce spontaneous regression of non-directly irradiated lesions, suggesting the involvement of systemic antitumor immune responses. In oligometastatic breast cancer (BC) patients, the use of stereotactic body radiotherapy (SBRT) favors the local control of treated lesions and may contribute to break local tolerance and release tumor-associated antigens (TAAs), improving host antitumor immunity. We performed a detailed immunomonitoring of BC patients undergoing SBRT to verify its ability to “switch on” the anti-tumor immunity both systemically, in peripheral blood, and locally, employing in vitro BC models. Twenty-one BC patients with ≤6 metastases were treated with 3 daily doses of 10 Gy with SBRT. Blood samples for immune profiling were collected before and after treatment. One month after treatment a third of patients displayed the boosting or even the de novo appearance of polyfunctional CD4+ and CD8+ T cell responses against known BC TAAs (survivin, mammaglobin-A, HER2), through intracellular staining in flow cytometry. Half of patients showed increased numbers of activated natural killer (NK) cells, measured with multispectral flow cytometry, immediately after the first dose of SBRT. Interestingly, high levels of activated NK cells at diagnosis correlated with a longer progression-free survival. BC in vitro models, treated with the same SBRT modality, showed enhanced expression of MHC class-I and class-II, major histocompatibility complex class I-related chain A/B, and Fas molecules, and increased release of pro-inflammatory cytokines, such as IL-1β and TNF-α. Consistently, we noticed enhanced production of perforin by CD4+ T cells when patients’ lymphocytes were cultured in the presence of irradiated BC cell line, compared to untreated targets. Besides immunogenic effects, SBRT also enhanced the percentages of circulating regulatory T cells, and increased indoleamine 2,3 dioxygenase and PD-L1 expression in BC in vitro models. These results suggest that SBRT may boost host antitumor immune responses also in an advanced disease setting such as oligometastatic BC, by inducing immunomodulating effects both locally and systemically. However, the concomitant induction of immunosuppressive pathways suggests that a combination with immunotherapy could further enhance the in situ vaccination ability of radiotherapy, possibly further improving the curative potential of SBRT in this subset of patients.

Stereotactic radiotherapy for prostate cancer: A review and future directions.

Prostate cancer affects over 200000 men annually in the United States alone. The role of conventionally fractionated external beam radiation therapy (RT) is well established as a treatment option for eligible prostate cancer patients; however, the use of stereotactic body radiotherapy (SBRT) in this setting is less well defined. Within the past decade, there have been a number of studies investigating the feasibility of SBRT as a potential treatment option for prostate cancer patients. SBRT has been well studied in other disease sites, and the shortened treatment course would allow for greater convenience for patients. There may also be implications for toxicity as well as disease control. In this review we present a number of prospective and retrospective trials of SBRT in the treatment of prostate cancer. We focus on factors such as biochemical progression-free survival, prostate specific antigen (PSA) response, and toxicity in order to compare SBRT to established treatment modalities. We also discuss future steps that the clinical community can take to further explore this new treatment approach. We conclude that initial studies examining the use of SBRT in the treatment of prostate cancer have demonstrated impressive rates of biochemical recurrence-free survival and PSA response, while maintaining a relatively favorable acute toxicity profile, though long-term follow-up is needed.

Inter-observer agreement in GTV delineation of bone metastases on CT and impact of MR imaging: A multicenter study

Background and purposeThe use of Stereotactic Body Radiotherapy (SBRT) for bone metastases is increasing rapidly. Therefore, knowledge of the inter-observer differences in tumor volume delineation is essential to guarantee precise dose delivery. The aim of this study is to compare inter-observer agreement in bone metastases delineated on different imaging modalities. Material and methodsTwenty consecutive patients with bone metastases treated with SBRT were selected. All patients received CT and MR imaging in treatment position prior to SBRT. Five observers from three institutions independently delineated gross tumor volume (GTV) on CT alone, CT with co-registered MRI and MRI alone. Four contours per imaging modality per patient were available, as one set of contours was shared by 2 observers. Inter-observer agreement, expressed in generalized conformity index [CIgen], volumes of contours and contours center of mass (COM) were calculated per patient and imaging modality. ResultsMean GTV delineated on MR (45.9±52.0cm3) was significantly larger compared to CT–MR (40.2±49.4cm3) and CT (34.8±41.8cm3). A considerable variation in CIgen was found on CT (mean 0.46, range 0.15–0.75) and CT–MRI (mean 0.54, range 0.17–0.71). The highest agreement was found on MRI (mean 0.56, range 0.20–0.77). The largest variations of COM were found in anterior–posterior direction for all imaging modalities. ConclusionsLarge inter-observer variation in GTV delineation exists for CT, CT–MRI and MRI. MRI-based GTV delineation resulted in larger volumes and highest consistency between observers.

A randomized phase II/III study comparing stereotactic body radiotherapy (SBRT) versus conventional palliative radiotherapy (CRT) for patients with spinal metastases (NCT02512965).

TPS10129 Background: Innovative radiotherapy technology and modern imaging capabilities enable the use of Stereotactic Body Radiotherapy (SBRT) to treat patients with spinal metastases to optimize tumour control and palliation compared to standard conventional radiotherapy. No randomized clinical trial evidence exists directly comparing the two treatment strategies. Methods: SC.24 is a Canadian Cancer Trials Group randomized phase II/III study comparing standard conventional radiotherapy (20 Gy/5fr) to SBRT (24 Gy/2fr) in patients with solid tumours and MRI documented, painful spinal metastases suitable for RT. The primary accrual objective for the phase II portion of the study was met in January 2017 and the study continues as a randomized phase III study with a primary outcome measure of complete pain response at 3 months post radiotherapy. Secondary objectives include: measurement of complete pain response at 6 months; radiation site progression free survival at 3 and 6 months; adverse event profile, health related QOL and compliance with RT QA measures. Biobanking for future correlative studies is included in study design. Statistical design: The statistical assumptions for the phase III study include estimated complete pain response rates of 10% and 30% for the CRT and SBRT treatment arms respectively. Using a two sided alpha = 0.05 and power = 80% the sample size for the phase III study is 152, taking into account a 5% drop out rate. Conduct to Date: Study activation: July 2015. Accrual to date: 58. Supported by CCSRI grant 021039 Clinical trial information: NCT02512965.

Salvage pulmonary resection after stereotactic body radiotherapy: A feasible and safe option for local failure in selected patients

ObjectiveFor inoperable patients with pulmonary malignancy, stereotactic body radiotherapy is a reasonable therapeutic option. Despite good early tumor control, local failure occurs in up to 10% of patients by 3 years. Because management of local recurrence after stereotactic body radiotherapy is unclear, we evaluated use of surgery as a salvage option. MethodsA retrospective review was conducted of consecutive patients from a single institution who underwent salvage resection of primary and metastatic pulmonary malignancies previously treated with stereotactic body radiotherapy. In addition, a literature search was conducted to identify previous reports of pulmonary resection for local stereotactic body radiotherapy failures, to allow cumulative analyses with previously published cases. ResultsA total of 21 patients met inclusion criteria. The median time between stereotactic body radiotherapy and salvage surgery was 16.2 months (range, 6.4-71.5). Postoperative complications occurred in 7 patients (18.9%), in whom atrial arrhythmias and prolonged air leaks (>5 days) were most frequent (n = 2 each, 5.4%). There was no local recurrence after salvage surgery. Distant failure occurred in 5 of 21 patients (23.8%) at a median of 36.2 months, and median disease-free survival was 19.2 months. The 30- and 90-day mortality was 4.8% (1 patient). Cumulative analysis included 37 patients from 4 institutions and comprised 26 (78.8%) primary non–small cell lung cancers and 11 (29.7%) lung metastases. Median overall survival after salvage surgery was 46.9 months, and 3-year survival was 71.8%. ConclusionsAfter local failure of stereotactic body radiotherapy, salvage resection remains a viable option for operable patients, with acceptable morbidity and survival. As use of stereotactic body radiotherapy continues to expand, further studies to evaluate the optimal management for local failure are needed.

A national analysis of wedge resection versus stereotactic body radiation therapy for stage IA non–small cell lung cancer

ObjectiveLobectomy is considered optimal therapy for early-stage non–small cell lung cancer, but sublobar wedge resection and stereotactic body radiation therapy are alternative treatments. This study compared outcomes between wedge resection and stereotactic body radiotherapy. MethodsOverall survival of patients with cT1N0 and tumors ≤2 cm who underwent stereotactic body radiotherapy or wedge resection in the National Cancer Data Base from 2008 to 2011 was assessed via a Kaplan-Meier and propensity score–matched analysis. A center-level sensitivity analysis that used observed/expected mortality ratios was conducted to identify an association between center use of stereotactic body radiotherapy and mortality. ResultsOf the 6295 patients included, 1778 (28.2%) underwent stereotactic body radiotherapy, and 4517 (71.8%) underwent wedge resection. Stereotactic body radiotherapy was associated with significantly reduced 5-year survival compared with wedge resection in both unmatched analysis (30.9% vs 55.2%, P < .001) and after adjustment for covariates (31.0% vs 49.9%, P < .001). Stereotactic body radiotherapy also was associated with worse overall survival than wedge resection after 2 subgroup analyses of propensity-matched patients (P < .05 for both). Centers that used stereotactic body radiotherapy more often as opposed to surgery for patients with cT1N0 patients with tumors <2 cm were more likely to have an observed/expected mortality ratio > 1 for 3-year mortality (P = .034). ConclusionsIn this national analysis, wedge resection was associated with better survival for stage IA non–small cell lung cancer than stereotactic body radiotherapy.

Stereotactic body radiotherapy vs. TACE or RFA as a bridge to transplant in patients with hepatocellular carcinoma. An intention-to-treat analysis

There is limited information on the use of stereotactic body radiotherapy (SBRT) as a bridge to liver transplantation for hepatocellular carcinoma and no study comparing its efficacy to transarterial chemoembolization (TACE) and radiofrequency ablation (RFA). We aimed to ascertain the safety and efficacy of SBRT on an intention-to-treat basis compared with TACE and RFA as a bridge to liver transplantation in a large cohort of patients with hepatocellular carcinoma. Outcomes between groups were compared from the time of listing and from the time of transplant. Between July 2004 and December 2014, 379 patients were treated with either SBRT (n=36, SBRT group), TACE (n=99, TACE group) or RFA (n=244, RFA group). The drop-out rate was similar between groups (16.7% SBRT group vs. 20.2% TACE group and 16.8% RFA group, p=0.7); 30 patients were transplanted in the SBRT group, 79 in the TACE group and 203 in the RFA group. Postoperative complications were similar between groups. Patients in the RFA group had more tumor necrosis in the explant. The 1-, 3- and 5-year actuarial patient survival from the time of listing was 83%, 61% and 61% in the SBRT group vs. 86%, 61% and 56% in the TACE group, and 86%, 72% and 61% in the RFA group, p=0.4. The 1-, 3- and 5-year survival from the time of transplant was 83%, 75% and 75% in the SBRT group vs. 96%, 75% and 69% in the TACE group, and 95%, 81% and 73% in the RFA group, p=0.7. In conclusion, SBRT can be safely utilized as a bridge to LT in patients with HCC, as an alternative to conventional bridging therapies. Patients with liver cancer included in the waiting list for liver transplantation are at risk of tumor progression and death. Stereotactic body radiotherapy may be a good alternative to conventional therapies to reduce this risk.

Trends and clinico-sociodemographic determinants of stereotactic body radiotherapy use for localized prostate cancer: A National Cancer Database study.

e545 Background: Stereotactic body radiotherapy (SBRT) represents an emerging and cautiously guideline-approved definitive therapy option for prostate cancer, though long-term data on efficacy and toxicity is still pending. Herein, we sought to determine contemporary national SBRT trends and clinico-sociodemographic determinants associated with its use in prostate cancer. Methods: The National Cancer Data Base (NCDB) was queried to identify 181,544 patients diagnosed with localized prostate cancer from 2004-2012 who received external beam radiotherapy. Multivariable logistic regression adjusted for sociodemographic and clinical factors was used to identify independent determinants of SBRT use. Results: Rate of SBRT use for localized prostate cancer increased from 0.05% in 2004 to 4.87% in 2012 ( Ptrend&lt; 0.001). SBRT was more likely to be delivered at academic centers, to patients with Medicare, and to patients who were white, younger, healthier, from wealthier and more educated zipcodes, and who had lower risk disease features (all P&lt; 0.001). Relative to Whites, men from more affluent zipcodes, or men with low stage or grade prostate cancer, Blacks, Hispanics, and men from less affluent zipcodes and men with high stage or grade prostate cancer were less likely to receive SBRT after multivariable adjustment, with adjusted hazard ratios of 0.66, 0.35, 0.33, 0.07, and 0.21, respectively (all P&lt; 0.001). Conclusions: The absolute national rate of SBRT use as definitive therapy for prostate cancer has increased nearly 100-fold over the last decade. Men who are White, younger, healthier, from more affluent zipcodes and with favorable disease characteristics are more likely to receive an emerging form of radiotherapy with unknown long-term efficacy and toxicity.

Use of stereotactic body radiotherapy for prostate cancer in the United States from 2004 through 2012.

Stereotactic body radiotherapy (SBRT) is a newer treatment option for patients with localized prostate cancer. The rates of diffusion of this technology across the United States are unknown. The goal of the current study was to describe the use of SBRT among patients with prostate cancer based on different risk groups (low, intermediate, or high risk) and by type of facility (community cancer program, comprehensive community cancer program, or academic program) in which patients were treated. Using the National Cancer Data Base, a national registry that contains approximately 70% of patients with cancer in the United States, the authors identified 274,466 men between the ages of 40 to 80 years who were diagnosed from 2004 to 2012 with localized prostate cancer and received radiation therapy (RT) as their initial treatment. The authors described the prevalence of SBRT use each year, and multivariable analysis was used to examine factors associated with the receipt of SBRT. In 2004, SBRT use was low (<1% in all patient groups), and was observed to increase steadily each year. By 2012, 8.8% of low-risk patients treated at academic centers with RT received SBRT. Uptake of SBRT was highest in patients with low-risk or intermediate-risk disease. Multivariable analysis demonstrated that year of diagnosis, type of center, risk group, and race were all significantly associated with the use of SBRT. To the authors' knowledge, the current study is the first report of the adoption of SBRT for localized prostate cancer across the United States. Diffusion was noted to be slowest at community cancer programs, reflecting potential barriers of cost or expertise for this new technology. Adoption of SBRT was found to be highest among patients with low-risk or intermediate-risk disease, in accordance with the bulk of patients included in published SBRT studies. Cancer 2016;122:2234-41. © 2016 American Cancer Society.

The use of stereotactic body radiotherapy as a bridge to liver transplantation for hepatocellular carcinoma.

418 Background: Approximately 30% of patients with hepatocellular carcinoma (HCC) on the wait list for liver transplant (LT) fall off the transplant list due to progressive HCC. Stereotactic Body Radiotherapy (SBRT) has been used as a “bridge” to LT in patients who are not amenable to RFA or TACE. Methods: Baseline patient characteristics, radiotherapy details and outcomes were reviewed in HCC patients who received SBRT as a bridge to LT. Results: Between July 2004 and Dec. 2014, 601 patients with HCC were listed for LT, of which 400 (66.5%) received bridging therapy. 38 patients, at high risk for HCC progression, were unsuitable for RFA or TACE, receiving SBRT as a bridging therapy. Median SBRT dose was 36Gy in 6 fractions (range 8.5-48Gy in 1 – 6 fractions), including 1 patient who was transplanted after receiving one fraction. 25 of 38 patients (67%) had all lesions treated (median number of lesions 2 {1-8}); 13 patients received SBRT only to the dominant lesion at highest risk of growing or rupturing. At the time of SBRT, 42% had HCC within Milan criteria, and median Child Pugh score was A6 (range A5-B8). 5 patients (13%) dropped off the transplant wait list due to development of metastatic disease (4) and macrovascular invasion with progressive disease (1). Median irradiated HCC volume was 60.5cc (range 7-216cc). Median liver volume (minus HCC) was 1491cc (737-2728cc). Median mean dose to the liver minus HCC was 11.2Gy (2.8-18.6Gy) and median effective liver volume irradiated was 28% (11-66%). 1 patient was admitted 2 months post SBRT with hepatic pain - possibly attributable to SBRT and another patient developed a rib fracture 8 months post SBRT (max rib dose 43Gy in 6 fractions). No other specific SBRT toxicity was noted. The 1-, 3- and 5-year disease free survival and actuarial survival of HCC patients treated with SBRT who went on to have transplant was 93%, 79% and 79%, and 89%, 76% and 76% respectively. Including patients who dropped off the transplant list, the intent-to-treat 1-, 3 - and 5-year survival was 89%, 65% and 65%. There was no reported increase in operative morbidity at the time of transplant in patients treated with SBRT. Conclusions: SBRT can be used safely and effectively in HCC patients as a bridge to liver transplant.

Practical patterns for stereotactic body radiotherapy to hepatocellular carcinoma in Korea: a survey of the Korean Stereotactic Radiosurgery Group

To investigate practical patterns for stereotactic body radiotherapy to hepatocellular carcinoma in Korea. In June 2013, the Korean Stereotactic Radiosurgery Group of the Korean Society for Radiation Oncology conducted a national patterns-of-care survey about stereotactic body radiotherapy to the liver lesion in hepatocellular carcinoma, consisting of 19 questions and 2 clinical scenarios. All 208 radiation oncologists (100%), who are regular members of Korean Society for Radiation Oncology, responded to this survey. Among these, 95 radiation oncologists were specialists for hepatology; 64 physicians did not use stereotactic body radiotherapy for hepatocellular carcinoma, and 31 physicians used stereotactic body radiotherapy. Most physicians (52%) performed stereotactic body radiotherapy to hepatocellular carcinoma in ≤5 cases per year. Physicians applied stereotactic body radiotherapy according to tumour size and baseline Child-Pugh class. All physicians agreed the use of stereotactic body radiotherapy to 2.8-cm hepatocellular carcinoma with Child-Pugh class of A, while 23 physicians (74%) selected stereotactic body radiotherapy for Child-Pugh class of B. Nineteen physicians (61%) selected stereotactic body radiotherapy to 5-cm hepatocellular carcinoma with Child-Pugh class of A, and only 14 physicians (45%) selected stereotactic body radiotherapy for Child-Pugh class of B. On the other hand, the preferred dose scheme was same as 60 Gy in three fractions. Among radiation oncologists in Korea, there was diversity in the practice for stereotactic body radiotherapy to the liver lesion in hepatocellular carcinoma. Additional prospective studies are necessary to standardize the practice and establish Korea-specific practice guidelines for hepatocellular carcinoma stereotactic body radiotherapy.

Outcomes of hypofractionated stereotactic body radiotherapy boost for intermediate and high-risk prostate cancer.

Background and purposeTreatment of intermediate and high-risk prostate cancer with a high BED has been shown to increase recurrence free survival (RFS). While high dose rate (HDR) brachytherapy, given as a boost is effective in delivering a high BED, many patients are not candidates for the procedure or wish to avoid an invasive procedure. We evaluated the use of stereotactic body radiotherapy (SBRT) as a boost, with dosimetry modeled after HDR-boost.Material and methodsFifty patients were treated with two fractions of SBRT (9.5-10.5 Gy/fraction) after 45 Gy external-beam radiotherapy, with 48 eligible for analysis at a median follow-up of 42.7 months.ResultsThe Kaplan-Meier estimates of biochemical control post-radiation therapy (95 % Confidence Interval) at 3, 4 and 5 years were 95 % (81–99 %), 90 % (72–97 %) and 90 % (72–97 %), respectively (not counting 2 patients with a PSA bounce as failures). RFS (defined as disease recurrence or death) estimates at 3, 4 and 5 years were 92 % (77–97 %), 88 % (69–95 %) and 83 % (62–93 %) if patients with PSA bounces are not counted as failures, and were 90 % (75–96 %), 85 % (67–94 %) and 75 % (53–88 %) if they were. The median time to PSA nadir was 26.2 months (range 5.8–82.9 months), with a median PSA nadir of 0.05 ng/mL (range <0.01–1.99 ng/mL). 2 patients had a “benign PSA bounce”, and 4 patients recurred with radiographic evidence of recurrence beyond the RT fields. Treatment was well tolerated with no acute G3 or higher GI or GU toxicity and only a single G3 late GU toxicity of urinary obstruction.ConclusionsSBRT boost is well-tolerated for intermediate and high-risk prostate cancer patients with good biochemical outcomes and low toxicity.

Efficient Protocol for the Identification of Hypoxic Cell Radiosensitisers.

An evolution in radiotherapy practice is leading to greater use of stereotactic body radiotherapy (SBRT), raising the prospect of increased hypoxic cell radioresistance. New clinical interest in nitroimidazole radiosensitisers, combined with appropriate biomarkers, signals a revival for radiosensitisers in the context of SBRT. Our interest in modifiers of radiation therapy led us to revisit this area and we have identified a new class of nitroimidazole radiosensitiser. We have developed an abbreviated screening protocol suitable for an academic drug discovery laboratory which allows expeditious triage of compounds with poor physicochemical and in vitro properties and combines in vitro radiosensitisation data with tumour pharmacokinetic data to efficiently select candidates for further evaluation.

Rebuttal from Ms Woodford and Dr Senthi.

Professor Nestle and Dr. Belderbos’ argument against the use of stereotactic body radiotherapy (SBRT) for central non-small cell lung cancer (NSCLC) centers on the fact there is little prospective high quality evidence to declare it safe. This is indeed true and highlights the importance of their multi-national phase II study (LungTech) and RTOG 0813 in guiding optimal patient care (1). However, there are aspects of their argument that should be discussed further, in particular data referenced from Cannon and Langendijk which may not be applicable to T2N0 central NSCLC.

Progression-free Survival Following Stereotactic Body Radiotherapy for Oligometastatic Prostate Cancer Treatment-naive Recurrence: A Multi-institutional Analysis

The literature on metastasis-directed therapy for oligometastatic prostate cancer (PCa) recurrence consists of small heterogeneous studies. This study aimed to reduce the heterogeneity by pooling individual patient data from different institutions treating oligometastatic PCa recurrence with stereotactic body radiotherapy (SBRT). We focussed on patients who were treatment naive, with the aim of determining if SBRT could delay disease progression. We included patients with three or fewer metastases. The Kaplan-Meier method was used to estimate distant progression-free survival (DPFS) and local progression-free survival (LPFS). Toxicity was scored using the Common Terminology Criteria for Adverse Events. In total, 163 metastases were treated in 119 patients. The median DPFS was 21 mo (95% confidence interval, 15–26 mo). A lower radiotherapy dose predicted a higher local recurrence rate with a 3-yr LPFS of 79% for patients treated with a biologically effective dose ≤100Gy versus 99% for patients treated with >100Gy (p=0.01). Seventeen patients (14%) developed toxicity classified as grade 1, and three patients (3%) developed grade 2 toxicity. No grade ≥3 toxicity occurred. These results should serve as a benchmark for future prospective trials. Patient summaryThis multi-institutional study pools all of the available data on the use of stereotactic body radiotherapy for limited prostate cancer metastases. We concluded that this approach is safe and associated with a prolonged treatment progression-free survival.

Stereotactic Body Radiotherapy for Prostate Cancer

The use of stereotactic body radiotherapy (SBRT) for localised prostate cancer is now supported by a substantial body of non-randomised data, with medium-term outcomes consistent with current standard radiotherapy. The ability to deliver profoundly hypofractionated treatment, combined with the relatively low α/β ratio of prostate cancer, may result in a more favourable therapeutic ratio, presenting an opportunity for isotoxic dose escalation. Furthermore, as treatment can be given in five attendances, SBRT has the potential both to reduce costs and improve patient quality of life. However, in a treatment landscape with many competing options of broadly similar efficacy, randomised trials are essential to define the relative benefits of this approach. SBRT also has an emerging application in oligometastatic prostate cancer, with promising early outcomes for delaying disease progression and deferring the need for androgen deprivation therapy.