Common Fractionation Schemes Research Articles

Effectiveness of palliative hemostatic radiotherapy for hemoptysis: a prospective single-arm observation study.

Palliative radiotherapy (RT) is commonly used for malignancy-associated hemoptysis. This study aims to determine RT control probability, durability, and influencing factors. This single-institution prospective observational study included patients ≥18 years old with any lung malignancy and active hemoptysis. Hemoptysis severity was captured and monitored via Common Terminology Criteria for Adverse Events (CTCAE) and an in-house developed Patient-Reported Outcome Measure (PROM) tool. Patients were interviewed at enrollment, 2 weeks, 3 months, and 6 months post-treatment. Descriptive statistics, the Kaplan-Meier (KM) method, the Wilcoxon signed-rank test, and Cox regression models were used. From April 2016 to November 2018, 41 patients were enrolled. One patient withdrew consent and was excluded. The median age was 68 years. Most patients were male (67%) with stage 4 (87.5%), lung primary (85%) disease, and Eastern Cooperative Oncology Group (ECOG) performance status ≥2 (55%). The most common fractionation scheme (72.5%) was 2,000 cGy in 5 fractions. Eight patients (20%) passed away before 2-week assessment. Median follow-up was 6.1 months (range, 0.9-6.2 months). The 6-month overall survival (OS) rate was 26% [95% confidence interval (CI): 13-41%]. The 6-month bleeding-related survival (BRS) was 95% (95% CI: 80-99%), and the 6-month freedom from hemoptysis rate was 37% (95% CI: 18-57%). No patient received re-irradiation for their hemoptysis. On univariate analysis, ECOG status (P=0.01) and prior radiation (P=0.006) were strongly associated with freedom from hemoptysis survival. Hemostatic RT remains an effective modality for controlling hemoptysis. The short interval high mortality rate post-RT challenges whether fractionated palliative RT should be used for this patient population. Conducting a large clinical trial with a hemoptysis PROM tool is necessary to identify hemostatic durability and influencing factors properly.

Efficacy and Safety of Multifraction Stereotactic Radiation Therapy with Volumetric Modulated Arc Therapy Technique for Multiple Brain Metastases

Multifraction stereotactic radiotherapy (MF-SRT) with volumetric modulated arc therapy (VMAT) is the standard treatment option for patients with multiple brain metastases. VMAT has superior physical accessibility and economic accessibility compared with advanced radiotherapy technologies such as Tomo or Proton radiotherapy. However, existing studies has mainly focused on comparing the dosimetric parameters between distinct radiotherapy techniques. Moreover, single fraction stereotactic radiosurgery is preferentially recommended for treatment of brain metastases with maximum diameter <2cm compared with MF-SRT. There is a lack of clinical results of its efficacy and subgroup analyses according to diameter. Thus, we first report the detailed analysis of clinical results of SRT using VMAT for brain metastases. This study is a retrospective analysis of SRT for multiple brain metastasis using VMAT. The clinical efficacy of VMAT was evaluated by local control (LC) in 6-months, 1-year, and 2-year. A total of 63 patients with 214 brain metastases were enrolled. The most common fractionation schemes were 40 Gy/8F and 48 Gy/12F. In all, LC rates at 6-month, 1-year, and 2-year were 95.5%, 90.6%, and 76.8%, respectively. Using univariate and multivariate analyses according to stratification factors including maximum diameter, GTV volume, dose per fraction, fractions, inner structure, and BED (α/β = 10), we found that no factors were associated with 6-month LC, 1-year LC, and 2-year LC. 1-year LC rates for maximum diameter ≥1 and <2, ≥2 and <3, and ≥3 cm were 89.2%, 90.7%, and 95.7%, respectively. The 1-year LC rates for tumors with GTV <3, ≥3 and <5, ≥5 and <10, and ≥10 cc were 87.0%, 91.7%, 94.7%, and 96.6%, respectively. Interestingly, 1year-LC in GTV ≥3 cc tends to higher than those in GTV <3 cc, but there was no significant difference (94.4% vs 87%, P = 0.162). Brain radionecrosis (RN) was the most significant toxicity occurring in 10 (4.7%) out of the 214 treated brain metastases. Among 6 patients with RN, 4 (66.7%) had been treated with tyrosine kinase inhibitors. The use of MF-SRT with VMAT for multiple brain metastases showed a comparable clinical efficacy to other techniques described in the literature. And the LC rate for maximum diameter <2cm treated with MF-SRT VMAT was comparable to single fraction stereotactic radiosurgery as previously reported. The treatment-related toxicity was acceptable.

Reirradiation with stereotactic body radiotherapy for primary or secondary lung malignancies: Tumor control probability and safety analyses

BackgroundReirradiation with stereotactic body radiotherapy (SBRT) for patients with primary or secondary lung malignancies represents an appealing definitive approach, but its feasibility and safety are not well defined. The purpose of this study was to investigate the tumor control probability (TCP) and toxicity for patients receiving reirradiation with SBRT. Patients and MethodsEligible patients with recurrence of primary or secondary lung malignancies from our hospital were subjected to reirradiation with SBRT, and PubMed- and Embase-indexed articles were reviewed. The patient characteristics, pertinent SBRT dosimetric details, local tumor control, and toxicities were extracted. The logistic dose–response models were compared for TCP and overall survival (OS) in terms of the physical dose and three-, four-, and five-fraction equivalent doses. ResultsThe data of 17 patients from our hospital and 195 patients extracted from 12 articles were summarized. Reirradiation with SBRT yielded 2-year estimates of 80% TCP for doses of 50.10 Gy, 55.85 Gy, and 60.54 Gy in three, four, and five fractions, respectively. The estimated TCP with common fractionation schemes were 50%, 60%, and 70% for 42.04 Gy, 47.44 Gy, and 53.32 Gy in five fractions, respectively. Similarly, the 2-year estimated OS was 50%, 60%, and 70% for 41.62 Gy, 46.88 Gy, and 52.55 Gy in five fractions, respectively. Central tumor localization may be associated with severe toxicity. ConclusionsReirradiation with SBRT doses of 50–60 Gy in 3–5 fractions is feasible for appropriately selected patients with recurrence of peripheral primary or secondary lung malignancies, but should be carefully considered for centrally-located tumors due to potentially severe toxicity. Further studies are warranted for optimal dose/fractionation schedules and more accurate selection of patients suitable for reirradiation with SBRT.

Radiotherapy of the Primary Tumor and All Metastatic Lesions in Oligometastatic Prostate Cancer

<h3>Purpose/Objective(s)</h3> The aim of this study was to evaluate the survival in oligometastatic prostate cancer patients treated with radiotherapy (RT) for both primary tumor and all metastatic lesions. <h3>Materials/Methods</h3> This was a single-center cohort study. Oligometastatic prostate cancer patients with RT for both primary tumor and all metastatic lesions were included. Kaplan–Meier method, log rank test and cox regression were used to calculate OS and PFS. PFS included PSA failure, local or distant failure assessed by imaging. <h3>Results</h3> This study analyzed 395 patients from 10/2011 to 1/2022 with median follow-up of 42 months. 264 patients (66.8%) were hormone sensitive (HSPC) and 131patients (33.2%) were castrate resistant (CRPC) at the time of RT. 212 patients (53.7%) were synchronous oligometastatic status, 58 patients (14.7%) were metachronous oligometastatic status, and 105 patients (26.6%) were oligoprogressive status. PSMA-PETCT was used for 238 men (60.3%). Before radiotherapy, 12 patients (3.0%) did not receive androgen deprivation therapy (ADT), 252 patients (63.8%) were treated with luteinizing hormone releasing hormone analogue (LHRHa) with or without bikaluamide. 131 patients (33.2%) were treated with LHRHa combined with novel ADT (abiraterone, enzalutamide, apalutamide, etc.), including 3 patients treated with enzalutamide, 2 patients treated with apalutamine, and the rest treated with abiraterone. The most common fractionation scheme of the primary tumor was 2.8Gy for 25 fractions (81.5%). The median BED₃ was 135.3Gy (IQR:128.3-135.3Gy). A total of 247 (62.5%) patients were treated with whole pelvic RT (WPRT). A total of 718 metastatic lesions were treated with RT. The median BED₃ was 121.3Gy (IQR:113.3-131.3Gy). For the whole cohort, the PFS and OS were 62.5% and 92.7% at 3 year, 53.1% and 81.7% at 5 years. Median PFS for men with HSPC was not reached compared with 10 months in men with CRPC. On univariable analysis, HSPC, shorter interval between diagnosis and RT, lower pre-RT PSA, lower Gleason score, lower metastatic burden/volume, use of WPRT, ADT type, chemotherapy were associated with improved PFS. <h3>Conclusion</h3> Our study suggests that RT for the primary tumor and all metastatic lesions has better survival than clinical studies of prostate radiotherapy alone, especially for patients with HSPC, shorter interval between diagnosis and RT and lower metastatic burden/volume.

Planning Tumor Volume and Local Control Following Stereotactic Body Radiation Therapy of Early-Stage NSCLC

<h3>Purpose/Objective(s)</h3> Stereotactic body radiation therapy (SBRT) is often used to treat primary early-stage non-small cell lung carcinoma (NSCLC) as an alternative to surgical management. The planning methods used for delivering SBRT differs across institutions with various planning target volume (PTV) margins utilized. The purpose of this study is to evaluate the impact of PTV margin and other factors on local control following SBRT. <h3>Materials/Methods</h3> A total of 283 patients with single lesion early-stage NSCLC treated with SBRT at our institution between 2017-2019 were included in this retrospective analysis. The median age was 75 years, with 57% female gender. Of the treated tumors, 68.6% were peripheral while 31.4% were central. Adenocarcinoma was the most common histology at 35.3% followed by 27.2% squamous cell carcinoma with other/unknown histology in the remaining 37.5% of patients. Mean gross tumor volume (GTV) was 9.7 cc (0.3-92.1) and mean PTV was 33.5 cc (5.3-170). The most common fractionation scheme used was 54 Gy in 3 fractions followed by 48 Gy in 4 fractions with mean biologically effective dose at α/β=10 (BED10) of 149.5 Gy. Local recurrence was based on recurrence of the treated lesion on follow-up imaging, defined as either significant enlargement not consistent with post-treatment radiation fibrosis or significant residual FDG-avidity if a PET/CT scan was obtained. Univariate analysis was performed via Kaplan-Meier analysis to analyze the association of local control with GTV volume, ratio of PTV to GTV volume, BED10, histology, and tumor location. <h3>Results</h3> The median follow-up was 1.6 years. Overall, 30 of the 283 patients (10.6%) developed a local recurrence. Kaplan-Meier analysis of local control and patients with a PTV to GTV ratio greater than the median of 4.74 showed statistically significant better local control at 3-years of 90.9% versus 67.7% (p=0.004). Local control was also significantly associated with GTV volume with 3-year local control of 91.9% for tumors <5 cc versus 67.7% for those >5 cc (p=0.007). The BED10 was significantly associated with local control with a 3-year local control of 82.2% for >150 Gy BED10 versus 78.3% for 100-150 Gy BED10 (p=0.016). Local control was not associated with histology (p=0.146) or central versus peripheral location (p=0.25). <h3>Conclusion</h3> Larger PTV to GTV ratio, smaller tumor volume, and a BED10 of greater than 150 Gy were significantly associated with better local control in patients treated with SBRT for early-stage NSCLC. These factors should be considered when treatment planning for SBRT in these patients.

Spine Stereotactic Body Radiotherapy for Prostate Cancer Metastases and the Impact of Hormone Sensitivity Status on Local Control.

Stereotactic body radiotherapy (SBRT) is used to deliver ablative dose of radiation to spinal metastases. To report the first dedicated series of spine SBRT specific to prostate cancer (PCa) metastases with outcomes reported according to hormone sensitivity status. A prospective database was reviewed identifying patients with PCa treated with spine SBRT. This included those with hormone-sensitive PCa (HSPC) and castrate-resistant PCa (CRPC). The primary end point was MRI-based local control (LC). A total of 183 spine segments in 93 patients were identified; 146 segments had no prior radiation and 37 had been previously radiated; 27 segments were postoperative. The median follow-up was 31 months. At the time of SBRT, 50 patients had HSPC and the remaining 43 had CRPC. The most common fractionation scheme was 24-28 Gy in 2 SBRT fractions (76%). LC rates at 1 and 2 years were 99% and 95% and 94% and 78% for the HSPC and CRPC cohorts, respectively. For patients treated with de novo SBRT, a higher risk of local failure was observed in patients with CRPC (P = .0425). The 1-year and 2-year overall survival rates were significantly longer at 98% and 95% in the HSPC cohort compared with 79% and 65% in the CRPC cohort (P = .0005). The cumulative risk of vertebral compression fracture at 2 years was 10%. Favorable LC rates were observed after spine SBRT for PCa metastases; strategies to improve long-term LC in patients with CRPC require further investigation.

Radiotherapy of the Primary Tumor and All Metastatic Lesions in Synchronous Oligometastatic Prostate Cancer

The aim of this study was to evaluate the survival in synchronous oligometastatic prostate cancer patients treated with radiotherapy (RT) for both primary tumor and all metastatic lesions.This was a single-center cohort study. Synchronous oligometastatic (≤5) prostate cancer patients with RT for both primary tumor and all metastatic lesions were included. Kaplan-Meier method, log rank test and cox regression were used to calculate OS and PFS. PFS included PSA failure, local or distant failure assessed by imaging.This study analyzed 60 patients from 10/2011 to 12/2017 with median follow-up of 48 months. All patients had metastatic disease at the time of initial diagnosis and all patients received androgen deprivation therapy (ADT). Forty-four (73%) patients were hormone sensitive (HSPC) and 16 (27%) patients were castrate resistant (CRPC) at the time of RT. PSMA PET/CT was used for 7 (12%) men. The most common fractionation schemes of the primary tumor were 2 Gy for 35-38 fractions (67%) and 2.7-2.8 Gy for 13 fractions (22%). The median BED3 was 126 Gy (range, 100-128 Gy). A total of 37 (62%) patients were treated with whole pelvic RT (WPRT). A total of 87 metastatic lesions were treated with RT. The median BED3 was 120 Gy for metastatic lesions (range, 63-139 Gy). For the whole cohort, the PFS and OS were 51.4% and 47.4% at 4 years. Median PFS for men with HSPC was 78 months compared with 11 months in men with CRPC. Median OS for men was 45 months in men with CRPC. On univariable analysis, HSPC, shorter interval between diagnosis and RT, lower pre-RT PSA, lower Gleason score, lower metastatic burden/volume, use of WPRT were associated with improved PFS.Our study suggests that RT for the primary tumor and all metastatic lesions plus systemic therapy has better survival than clinical studies of prostate radiotherapy alone, especially for patients with HSPC, shorter interval between diagnosis and RT and lower metastatic burden/volume.

Effectiveness of surface mould brachytherapy in electron era.

e21562 Background: In India, skin cancers constitute about 1-2% of all diagnosed cancers.Surgery stays main modality of treatment with adequate surgical margin shown excellent local control rates - generally 95%.However, conditions where surgery is not feasible, brachytherapy is alternative approach.Advanced technology improved the ability to deliver safe and effective radiotherapy, resulting in renewed interest in this modality.Brachytherapy has many advantages: they can deposit a significantly higher dose within a tumor, with better sparing of adjacent normal structures over external beam radiotherapy or electron therapy, which sometimes require irradiating a large volume of tissue in order to provide adequately coverage, which in term increase toxicity. The purpose of our paper is to find out the clinical outcomes of skin tumors and superficial tumours of head and neck region treated with Surface mould brachytherapy (SMB), in terms of survival and toxicity.We report on our institution’s experience with using Co-60 based HDR SMB for the treatment of skin and head and neck superficial malignancies. Methods: A retrospective review of all patients treated with surface mould Co-60-based HDR brachytherapy at our center.A total of 23 patients, with 23 lesions, were treated during this period, and included in the analysis. A total of three of these lesions were treated with a palliative intent, and were included. The most common fractionation scheme was 35 Gy in 10 fractions given daily (52%, n = 12), though a range of doses were used, from 8/2 fractions to 36 Gy/12 fractions. Results: Median age at diagnosis was 52 (range = 28-91). The majority were Squamous cell (43%, n = 10) or Basal cell carcinomas (34%, n = 8). Most lesions were located in the head and neck region. The most commonly used RT dose was 3GyX10 fractions; all patients had individualized CT-based planning.The 5-year overall survival (OS) was 86 %( twenty patients). Three patients were died. Most deaths were from unrelated causes. Response was assessed in OPD 2-4 months post-treatment. Our complete response (CR) rate was 73.9% (seventeen patients), with partial response in three patients; two patients could not be assessed for response and one patient died due to other medical condition. We report a 2-year local control (LC) rate of 91.3%, and local recurrence was found in two patients. The procedure was well tolerated, with no grade 3 or more acute or late toxicities. There was one case of grade 3 ulcer (CTCAE). The 100% isodose line median depth was 0.5 cm, and median surface dose = 126.5%. The median V90 = 92.3%. Conclusions: Surface mould brachytherapy is a safe, effective modality for treatment of skin malignancies or tumors. Brachytherapy was overall well tolerated, with no grade 3-5 acute or late toxicities. This treatment is a good alternative option for those patients unwilling or unable to undergo surgery for their skin malignancies

Stereotactic Body Radiation Therapy for Spinal Metastases: Tumor Control Probability Analyses and Recommended Reporting Standards

We sought to investigate the tumor control probability (TCP) of spinal metastases treated with stereotactic body radiation therapy (SBRT) in 1 to 5 fractions. PubMed-indexed articles from 1995 to 2018 were eligible for data extraction if they contained SBRT dosimetric details correlated with actuarial 2-year local tumor control rates. Logistic dose-response models of collected data were compared in terms of physical dose and 3-fraction equivalent dose. Data were extracted from 24 articles with 2619 spinal metastases. Physical dose TCP modeling of 2-year local tumor control from the single-fraction data were compared with data from 2 to 5 fractions, resulting in an estimated α/β = 6 Gy, and this was used to pool data. Acknowledging the uncertainty intrinsic to the data extraction and modeling process, the 90% TCP corresponded to 20 Gy in 1 fraction, 28 Gy in 2 fractions, 33 Gy in 3 fractions, and (with extrapolation) 40 Gy in 5 fractions. The estimated TCP for common fractionation schemes was 82% at 18 Gy, 90% for 20 Gy, and 96% for 24 Gy in a single fraction, 82% for 24 Gy in 2 fractions, and 78% for 27 Gy in 3 fractions. Spinal SBRT with the most common fractionation schemes yields 2-year estimates of local control of 82% to 96%. Given the heterogeneity in the tumor control estimates extracted from the literature, with variability in reporting of dosimetry data and the definition of and statistical methods of reporting tumor control, care should be taken interpreting the resultant model-based estimates. Depending on the clinical intent, the improved TCP with higher dose regimens should be weighed against the potential risks for greater toxicity. We encourage future reports to provide full dosimetric data correlated with tumor local control to allow future efforts of modeling pooled data.

High-dose-rate brachytherapy for non-melanoma skin cancer using tailored custom moulds - a single-centre experience.

Aim of the studyThe aim of this retrospective study was to analyse tumour control, toxicity, and aesthetic outcome of patients affected by non-melanoma skin cancer (NMSC) treated with 192 Ir high-dose-rate (HDR)-brachytherapy (BT) at the Division of Radiotherapy, University of Pisa.Material and methodsFrom January 2014 to December 2019 we treated 37 patients (median age 79 years; range 31–91 years) affected by NMSC, with the following histological subtypes: 62.2% basal cell carcinoma and 37.8% squamous cell carcinoma. We analysed 40 lesions with a depth ≤ 5 mm, located in 40.0% scalp, 17.5% nose, 25.0% face, and 17.5% ear, all treated with 192 Ir-based HDR-BT, using tailored custom moulds, with a median of 5 catheters (range, 1–9) spaced 1 cm apart. The most common fractionation scheme was 40 Gy in 8 daily fractions; the biological effective dose was 60 Gy.ResultsThe median follow-up was 25 months (range, 3–70 months). The 2-year local control rate was 90%. Common terminology criteria for adverse event (CTCAE vs. 5.0) G1 toxicities were dermatitis (52%), pain (25%), and ulceration (22%). The only G2 acute toxicities were dermatitis and ulceration. The most common G1 late toxicities were fibrosis (17%), atrophy (15%), and hypopigmentation (12%). No G3 or higher acute or late toxicity was reported. Excellent cosmetic results were observed in 65.0% of the lesions; only 1 case (2.5%) reported a poor cosmetic result.ConclusionsSurface mould HDR-BT is a safe, effective, and well tolerated treatment modality for NMSC and can be considered a good alternative, especially for elderly patients who are often unfit for surgery.

Rates Of Radionecrosis In Re-Irradiation Of Brain Metastases Using Hypofractionated Stereotactic Radiotherapy

Improved overall survival rates among brain metastases (BM) patients have led to higher rates of salvage re-irradiation in patients with local failure. Hypofractionated stereotactic regimens are an attractive option due to the possibility of lower rates of radionecrosis (RN). This study aims to determine the incidence and risk factors of RN following re-irradiation with hypofractionated stereotactic radiotherapy (hSRT) and compares the results to the incidence of RN following re-irradiation with single fraction SRS reported in literature. Retrospective chart review was conducted on patients from a single institution who received re-irradiation using hSRT to BMs that previously received stereotactic radiotherapy. Patients who received additional whole brain radiation (WBRT), prior to, or after stereotactic radiotherapy were included. Patient, tumor, treatment characteristics, and follow-up data were collected. MRI and pathology of any lesions resected post-radiotherapy were reviewed to assess for the development of RN and the response to treatment. RN was confirmed through MRI or by surgical resection. Associations between RN and target volume, as well as number of months between stereotactic treatments were examined using logistic regression. Association between RN and use of additional WBRT was examined using relative risk and chi-square tests. A total of 110 metastatic brain lesions in 90 patients received hSRT reirradiation between August 2010 and December 2019. 26.7% (n = 24) of patients also received additional WBRT. The most common histologies were breast (n = 31), NSCLC (n = 30), and melanoma (n = 29). The median volume of lesions was 12.25cc (IQR 4.97 – 25.07cc). The most common fractionation scheme was 25 Gy in 5 fractions (72 lesions). The incidence of local failure was 11.6% and 17.4% at 6 and 12 months, respectively. Incidence of symptomatic RN was 6.15% and 15% at 6 and 12 months, respectively. There was no statistically significant association between symptomatic RN at 12-months and radiation dose (p = 0.40), target volume (p = 0.96), use of additional WBRT (p = 0.74), or number of months between SRT (p = 0.99). The incidence of symptomatic RN following re-irradiation with hSRT is lower compared to re-irradiation with single fraction SRS as reported in literature. hSRT provides an alternative salvage option for treating local failure of BMs to reduce risk of RN while achieving local control.

Effectiveness of Palliative Hemostatic Radiotherapy for Hemoptysis; A Prospective Single Arm Observational Study

Palliative external beam radiotherapy is commonly used for malignancy associated hemoptysis. Few studies have focused on the effectiveness of radiotherapy in a cohort of patients with uncontrolled bleeding. The purpose of this study is to determine radiotherapy control probability, durability and influencing factors. This is a single institution prospective observational study that included patients ≥18 years with any lung malignancy and active hemoptysis at time of presentation. Hemoptysis severity was captured and monitored via an in-house developed patient reported outcome tool. The tool captures bleeding description, amount and frequency within 1 week prior to presentation and assigns a cumulative score ranging from 0-12. Patients were interviewed at enrollment, 2 weeks, 3 months and 6 months post treatment. Definition of a complete response was a total score of 0, partial response was a decrease from baseline score but >0, and progression was an increase from baseline score. Descriptive statistics, Kaplan-Meier method, Wilcoxon signed-rank test and Cox regression models were used. From April 2016 to November 2018, 41 patients were enrolled. One patient withdrew consent and was excluded. Median age was 68 years. The majority of patients were male (67%) with stage 4 (87%), lung primary (85%) disease and ECOG performance status 2 (55%). Prior to enrollment, 15% of patients received a blood transfusion and 5% had a bleeding associated intervention. Median baseline bleeding score was 7 (IQR; 5-8). Most common fractionation scheme (72.5%) was 2000 cGy in 5 fractions. Median Planning Target Volume (PTV) was 364 cc. Median follow up was 6.1 months (range 0.9-6.2). Forty patients had scores available at baseline versus 32, 19 and 10 scores at 2 weeks, 3 and 6 months. Complete response was achieved in 17 (53%) of surviving patients at 2 weeks (z= -4.2, p<0.001), 15 (79%) at 3 months (z= -3.5, p<0.001) and 8 (80%) at 6 months (z= -2.6, p=0.004). Of the patients with complete hemoptysis response, 2 (20%) recurred at 3 months and 1 (16%) at 6 months. The 6-month OS was 26% (95% CI 0.13, 0.41). No patient received re-radiation for their hemoptysis. On univariate analysis, ECOG status (p=0.012) and prior radiation (p=0.006) were strongly associated with freedom from hemoptysis survival, while baseline hemoptysis score was borderline (p=0.072). Multivariate analysis was not performed due to small sample size. Hemostatic radiotherapy is an effective modality for controlling hemoptysis in a poor prognosis population with acceptable durability and no re-treatments required. However, a larger sample size is required to assess the impact of influencing factors.

Density-based fractionation of soil organic matter: effects of heavy liquid and heavy fraction washing

Physical fractionation methods used in soil organic matter (SOM) research commonly include density-based procedures with heavy liquids to separate SOM pools with varying turnover rates and functions. Once separated, the heavy SOM pools are often thoroughly rinsed with water to wash off any residues of the heavy liquids. Using four soils with contrasting properties, we investigated the effects of using either sodium polytungstate (SPT) or sodium iodide (NaI), two of the most commonly used heavy liquids, on the distribution of organic carbon (C) and total nitrogen (N) in free light, intra-aggregate light, and mineral-associated heavy SOM pools isolated by a common fractionation scheme. We also determined the effects of washing the mineral-associated heavy SOM fractions on the recovery of organic C and total N after separation. Because of its smaller viscosity compared to that of NaI, SPT consistently yielded greater intra-aggregate and smaller mineral-associated soil organic C contents. We also confirm that some commercial SPT products, such as the one used here, can contaminate organo-mineral heavy pools with N during density-based fractionation procedures. We do not recommend the repeated washing of heavy fractions separated with Na-based heavy liquids, as this can mobilize SOM.

Stereotactic Body Radiation Therapy to Multiple Sites of Intrathoracic Disease: A Multi-Institutional Analysis

There are limited data regarding the safety of stereotactic body radiotherapy (SBRT) to multiple sites of intrathoracic disease. We sought to assess rates of radiation pneumonitis (RP) and outcomes for patients treated with SBRT to multiple intrathoracic tumors. Thirty-eight patients with 84 synchronous (within 3 months) or metachronous lung nodules were treated with a total of 72 courses of SBRT between 2009 and 2017 at three tertiary hospitals. Clinical and dosimetric data were collected. Rates of RP (graded per CTCAE v4.0) and Kaplan-Meier estimates of oncological outcomes were calculated. Thirty-one patients were treated to 2 sites of disease, while six patients were treated to 3 sites, and one patient was treated to 4 sites. Nine patients received SBRT to two lesions simultaneously with one plan, while 13 and 9 patients received SBRT to synchronous or metachronous lesions, respectively. The median time interval between SBRT courses was 28.5 days (IQR: 18.5-43 days) for synchronous lesions and 14.7 months (IQR: 8.5-24.8) for metachronous lesions. Fifty-six (66.7%) of the treated lesions were primary lung cancers, while 28 (33.3%) were metastatic nodules (included for RP endpoint only). The most common fractionation scheme was 50 Gy in 5 fractions. Seventy-nine (94.0%) nodules received a biological effective dose of at least 100Gy. The median treated nodule size was 1.8 cm (IQR: 1.2-2.7). Median follow-up from the first SBRT course was 29.0 months. Grade 2 RP was diagnosed in 2 patients (5.2%) following the first SBRT course and 1 patient (2.6%) following the second SBRT course. Grade 3 RP was diagnosed in 2 patients following the second SBRT course (5.2%). Neither the number of treated sites nor the number of SBRT courses was associated with development of RP (P=0.48 and P=0.15, respectively) or grade of radiation pneumonitis (P=0.64 and P=0.16, respectively). Eighteen patients with a median age of 74 years (IQR: 67-80) received at least 2 courses of SBRT to a total of 40 primary Stage IA-IIB non-small cell lung cancers (NSCLC). At a median of 22.8 months (IQR: 14.0-40.9), the in-site recurrence rate was 5.6% (N=1), the ipsilateral lung recurrence rate was 27.8% (N=5), and the distant recurrence rate was 38.9% (N=7). The Kaplan-Meier estimate for 3-year freedom from in-site recurrence was 91.7% (95% CI: 77.3-100.0), 3-year freedom from locoregional recurrence was 63.1% (95% CI: 39.0-100.0), and 3-year overall survival was 62.5% (95% CI: 40.7-95.9). In this series of patients, more than one course of SBRT to synchronous or metachronous intrathoracic tumors was not associated with higher rates of RP. Excellent locoregional control was achieved among patients treated for early stage NSCLC. While larger studies are required, receipt of previous SBRT should not necessarily preclude consideration of further SBRT.

Trends in Regimen for Palliative Radiation Therapy of Bone Metastases in Patients with Non-Small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) is among one of the most common solid malignancies associated with bone metastases (BM). Palliative radiation therapy (RT) is the standard of care to alleviate symptoms associated with BM. Multiple randomized trials have shown equivalent pain relief with single fraction or short-course RT compared to longer palliative RT courses. In this study, we reviewed the NCDB to report on trends of short- and long-course palliative RT for BM in patients with NSCLC. There were 10,271 patients with NSCLC and BM treated with palliative RT between 2004 and 2014 were identified in the NCDB. Fractionation scheme was defined as short-course [(SC-RT): 8 Gy in 1 fractions and 20 Gy in 5 fractions] versus long-course [(LC-RT): 30 Gy in 10 fractions and 37.5 Gy in 15 fractions]. Patients coded with metastases to the ‘spinal cord’ were excluded. Trends in use of SC-RT versus LC-RT in the years 2004-2014 were analyzed with Chi Square test and ANOVA. Patient demographics and disease characteristics were correlated with fractionation scheme using multivariable logistic regression. A total of 1933 (18.8%) patients were included in the SC-RT group and 8338 (81.2%) patients in the LC-RT group. Sites of BM were spine (57.2%), extremity (13.9%), hip/pelvis (21.9%) ribs (6.1%), and skull (0.9%). The use of SC-RT has increased from 12.2% in 2004 to 27.6% in 2014 (p<0.0001). Factors associated with increased use of SC-RT included: academic treatment facility [Odds ratio (OR): 0.58 (95% CI, 0.52-0.65); p<0.0001], living > 20 miles from treatment facility [OR: 0.69 (95% CI, 0.55-0.87); p=0.002], treatment to the rib [OR: 0.68 (95% CI, 0.55-0.84); p<0.0001], treatment in the year 2010 [OR: 0.63 (95% CI, 0.46-0.85); p=0.003], treatment in the year 2011 [OR: 0.55 (95% CI, 0.41-0.74); p<0.0001], treatment in the year 2012 [OR: 0.55 (95% CI, 0.41-0.74); p<0.0001], treatment in the year 2013 [OR: 0.43 (95% CI, 0.32-0.57); p<0.0001], and treatment in 2014 [OR: 0.37 (95% CI, 0.28-0.49); p<0.0001]. Increasing age trended toward association of SC-RT [OR: 0.99 (95% CI, 0.99-1.00); p=0.071] though did not reach statistical significance. Factors associated with increased utilization of LC-RT included living <5 miles to treatment facility [OR: 1.15 (95% CI, 1.01-1.30); p=0.029], treatment to the hip/pelvis [OR: 1.43 (95% CI, 1.21-1.67); p<0.0001], and treatment to the spine [OR: 2.51 (95% CI, 2.17-2.90); p<0.0001]. Our analysis reveals that LC-RT remains the most common fractionation scheme for palliative treatment of BM in NSCLC patients. Use of palliative short-course RT is increasing, and has more than doubled between 2004 and 2014. SC-RT is more common in academic facilities and for patients who live a large distance from a treatment facility. Although randomized evidence supports equivalent pain relief with SC-RT, its use remains under-utilized and requires further advocacy for palliative treatment of BM.

A survey of stereotactic radiation therapy in veterinary medicine.

Radiotherapy plays an important role in curative and palliative cancer treatment. As a novel radiation delivery technique, stereotactic radiotherapy utilizes three-dimensional-conformal treatment planning, high-precision beam delivery technology, and patient specific position verification to target tumors, often in one to five high-dose fractions. Currently, there is no consensus about best stereotactic radiotherapy practices in veterinary radiotherapy. The objective of this study was to document the breadth of perspectives, techniques, and applications of stereotactic radiotherapy in veterinary medicine. We conducted an online survey of American College of Veterinary Radiology members specializing in radiation oncology to assess how, when, and why stereotactic radiotherapy is being used. Both stereotactic radiotherapy users and nonusers completed the survey. The overall response and survey completion rates were 54% (67/123) and 87% (58/67), respectively. Overall, 55% of respondents reported providing stereotactic radiotherapy at their facility, with a median of 4.5 canine cases and one feline case per month. Delivery methods included C-arm linear accelerator with multi-leaf collimator, helical tomotherapy, and CyberKnife. Nonpituitary intracranial tumors, pituitary tumors, and sinonasal tumors were the most common cancers treated using stereotactic radiotherapy in both species. The most common fractionation scheme was three fractions of 10Gy/fraction. The results of this survey suggest common availability of stereotactic radiotherapy in veterinary radiation facilities. These results provide valuable information regarding current stereotactic radiotherapy practices in veterinary medicine, and may provide an initial step toward standardizing methods and establishing consensus guidelines.

Use of Helical TomoTherapy for the Focal Hypofractionated Treatment of Limited Brain Metastases in the Initial and Recurrent Setting.

Background: Whole-brain radiation therapy (WBRT), stereotactic radiosurgery (SRS), or both are commonly employed in the treatment of limited brain metastases in the initial or recurrent setting. Hypofractionated partial volume irradiation is also employed, however, published experience using helical TomoTherapy (HT) for this purposes is limited. We reviewed our institutional experience to assess patient selection factors, fractionation scheme, and outcomes associated with this technique.Methods: A retrospective chart review was performed to evaluate patients treated with partial volume hypofractionated HT-based IMRT for brain metastases at our institution.Results: Thirteen patients (7M/6F, median age 62, median KPS 90) with a limited (1–9) number of brain metastases in the primary or recurrent setting were identified. Primary malignancies included colorectal (3), NSCLC (5), RCC (1), breast (1), melanoma (1), uterine (1), and ovarian (1). The median time from initial diagnosis to brain metastases was 20.7 months (range 0–61.3). Treatment was delivered to intact metastases in six patients, to a single resection cavity in six patients, and to both in one patient. A total of 27 lesions were treated. The median number of intact metastases treated was two (range 1–9). Previous treatments included WBRT (5), WBRT + SRS (3), SRS alone (1), and none (4). The most common fractionation schemes were 25 Gy in five fractions and 27.5 Gy in five fractions to each lesion. At a median of 6 months follow up (range 1.26–20.13) after TomoTherapy, 10 patients were deceased, 2 were alive, and 1 was lost to follow up. Systemic progression occurred in seven patients and intracranial progression occurred in five. The median intracranial progression free survival and overall survival after TomoTherapy was 6.3 months. Freedom from local failure for treated lesions was 71% and 59% at 6 and 12 months.Conclusion: TomoTherapy-based hypofractionated radiotherapy to a limited number of metastatic lesions is associated with acceptable intracranial disease control and survival outcomes and represents a viable treatment option in the primary and recurrent setting for select patients.

RT-34 * USE OF HELICAL TOMOTHERAPY FOR HYPOFRACTIONATED TREATMENT OF LIMITED BRAIN METASTASES IN THE INITIAL AND RECURRENT SETTING: A SINGLE INSTITUTION EXPERIENCE

BACKGROUND: Whole brain radiation therapy (WBRT), stereotactic radiosurgery (SRS), or both are commonly employed in the treatment of limited brain metastases in the initial or recurrent setting. Hypofractionated partial volume irradiation is also employed, however published experience using helical TomoTherapy for this purposes is limited. We reviewed our institutional experience to assess patient selection factors, fractionation scheme, and outcomes associated with this technique. METHODS: A retrospective chart review was performed to evaluate patients treated with partial volume hypofractionated helical TomoTherapy-based IMRT for brain metastases at our institution. RESULTS: Thirteen patients (7M/6F, median age 62, median KPS 90) with a limited (1-9) number of brain metastases in the primary or recurrent setting were identified. Primary malignancies included colorectal (3), NSCLC (5), RCC (1), breast (1), melanoma (1), uterine (1) and ovarian (1). The median time from initial diagnosis to identification of brain metastases was 21 months (range 0-61.3 months). Treatment was delivered to intact metastases in 6 patients, to a single resection cavity in 6 patients, and to both in one patient. The median number of intact metastases treated was 2 (range 1-9). The most common fractionation schemes were 25 Gy in 5 fractions and 27.5 Gy in 5 fractions to each lesion. Previous treatments included WBRT (5), WBRT + SRS (3), SRS alone (1), and none (4). At a median of 6 months follow up (range 1.26-20.13 months) after TomoTherapy, 10 patients were deceased, 2 were alive, and one was lost to follow up. Systemic progression occurred in 7 patients and intracranial progression occurred in 5. The median intracranial progression free survival and overall survival after TomoTherapy was 6.3 months. CONCLUSIONS: TomoTherapy-based hypofractionated radiotherapy to a limited number of metastatic lesions is associated with favorable intracranial disease control and survival outcomes in the primary and recurrent setting for select patients.

Equivalent uniform dose for accelerated partial breast irradiation using the MammoSite applicator

IntroductionThis study aims to quantify the radiobiology of the MammoSite applicator and examine whether there is a relationship between equivalent uniform dose (EUD) and radiotherapy-associated toxicity. Methods and materialsA previously-published version of the linear quadratic (LQ) model, designed to address the impact of dose-gradients in brachytherapy applications, was used to determine the biological effective dose (BED), equivalent dose in 2 Gray per fraction (EQD2) and EUD for the most common fractionation scheme for the MammoSite catheter (34Gy in 10 fractions prescribed to 1cm from the balloon surface), using a range of balloon sizes in a series of patients treated with single or multiple dwell positions. Toxicity from the MammoSite catheter was assessed and statistical associations with the calculated EUDs were investigated. ResultsThe acute- and late-toxicity EUDs respectively range from 34.8–39.4Gy and 33.4–37.6Gy, with EUD decreasing as balloon diameter increases and/or the number of dwell positions increases. There was a positive association between EUD and hyperpigmentation and telangiectasia. ConclusionsFor APBI using the Mammosite applicator, EUD is higher than the marginal prescription dose and, for the dose-fractionation patterns considered here, was associated with acute and late skin toxicity. EUD is a potentially useful parameter to characterize non-uniform dose distributions related to brachytherapy treatments. Further evaluation in future studies is warranted.

Biologically Equivalent Dose Volume Parameter Comparison of Common Fractionation Schemes used in HDR Brachytherapy Treatment of Cervical Cancer Patients

Biologically Equivalent Dose Volume Parameter Comparison of Common Fractionation Schemes used in HDR Brachytherapy Treatment of Cervical Cancer Patients