Dataset Information

Stereotactic ablative radiotherapy for ultra-central lung tumors: prioritize target coverage or organs at risk?

ABSTRACT: Lung stereotactic ablative radiotherapy (SABR) is associated with low morbidity, however there is an increased risk of treatment-related toxicity in tumors directly abutting or invading the proximal bronchial tree, termed 'ultra-central' tumors. As there is no consensus regarding the optimal radiotherapy treatment regimen for these tumors, we performed a modeling study to evaluate the trade-offs between predicted toxicity and local control for commonly used high-precision dose-fractionation regimens.Ten patients with ultra-central lung tumors were identified from our institutional database. New plans were generated for 3 different hypofractionated schemes: 50 Gy in 5 fractions, 60 Gy in 8 fractions and 60 Gy in 15 fractions. For each regimen, one plan was created that prioritized planning target volume (PTV) coverage, potentially at the expense of organ at risk (OAR) tolerance, and a second that compromised PTV coverage to respect OAR dose constraints. Published radiobiological models were employed to evaluate competing treatment plans based on estimates for local control and the likelihood for toxicity to OAR.The risk of esophageal or pulmonary toxicity was low (

SUBMITTER: Murrell DH

PROVIDER: S-EPMC5880025 | biostudies-literature | 2018 Apr

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Stereotactic ablative radiotherapy for ultra-central lung tumors: prioritize target coverage or organs at risk?

Murrell Donna H DH Laba Joanna M JM Erickson Abigail A Millman Barbara B Palma David A DA Louie Alexander V AV

Radiation oncology (London, England) 20180402 1

<h4>Background</h4>Lung stereotactic ablative radiotherapy (SABR) is associated with low morbidity, however there is an increased risk of treatment-related toxicity in tumors directly abutting or invading the proximal bronchial tree, termed 'ultra-central' tumors. As there is no consensus regarding the optimal radiotherapy treatment regimen for these tumors, we performed a modeling study to evaluate the trade-offs between predicted toxicity and local control for commonly used high-precision dose ...[more]

PMID: 29606150

Similar Datasets

Project description:Prostate is the most common non-cutaneous cancer diagnosed among men in North America. Fortunately most prostate cancers are screen detected and non-metastatic on diagnosis. Treatment options for men with localized prostate cancer include surgery ± postoperative radiation or radiation ± androgen deprivation therapy (ADT). Brachytherapy ± external beam radiation treatment (EBRT) appears to have superior long-term disease control over EBRT alone likely because of higher biologic effective dose delivered. Stereotactic ablative body radiation (SABR) is a novel, non-invasive, high-precision EBRT technique that allows safe delivery of biologic doses similar to brachytherapy with similar or lower side effects [measured using toxicity or quality of life (QOL) scales]. Efficacy for SABR appears to be similar to brachytherapy including positive biopsy rates 2-3 years post treatment, biochemical failure (BF) rates out to 10-year and incidence of metastases. SABR dose escalation reduces biopsy positivity and prostate-specific antigen (PSA) nadirs but increases genitourinary (GU) and gastrointestinal (GI) toxicity-no effect on BF has been realized yet. The overall treatment time (OTT) varies in many protocols. Phase 2 randomized data shows that QOL is better in the acute setting with a weekly course of treatment compared to an every other day treatment regimen with no difference in late setting. Follow-up data are immature and likely underpowered to determine efficacy differences. SABR is cheaper and uses less resource than any other radiation technique. Given the healthcare resource challenges (including financial resources), SABR would be a welcomed addition if studies show non-inferiority to other radiation techniques. For patients with de novo or metastatic disease on relapse, there is much enthusiasm regarding the use of SABR in the setting of oligometastatic prostate cancer. SABR appears to be feasible to deliver, well tolerated and may delay the next line of therapy. However, until adequately powered randomized studies confirm a benefit, such an approach cannot be considered standard of care treatment at this time. Enrollment of eligible prostate cancer patients onto SABR clinical trials should be encouraged.

Project description:PurposeTo explore the benefit of adaptive magnetic resonance-guided stereotactic body radiotherapy (MRgSBRT) for treatment of lung tumors in different locations with a focus on ultracentral lung tumors (ULT).Patients & methodsA prospective cohort of 21 patients with 23 primary and secondary lung tumors was analyzed. Tumors were located peripherally (N = 10), centrally (N = 2) and ultracentrally (N = 11, planning target volume (PTV) overlap with proximal bronchi, esophagus and/or pulmonary artery). All patients received MRgSBRT with gated dose delivery and risk-adapted fractionation. Before each fraction, the baseline plan was recalculated on the anatomy of the day (predicted plan). Plan adaptation was performed in 154/165 fractions (93.3%). Comparison of dose characteristics between predicted and adapted plans employed descriptive statistics and Bayesian linear multilevel models. The posterior distributions resulting from the Bayesian models are presented by the mean together with the corresponding 95% compatibility interval (CI).ResultsPlan adaptation decreased the proportion of fractions with violated planning objectives from 94% (predicted plans) to 17% (adapted plans). In most cases, inadequate PTV coverage was remedied (predicted: 86%, adapted: 13%), corresponding to a moderate increase of PTV coverage (mean +6.3%, 95% CI: [5.3-7.4%]) and biologically effective PTV doses (BED10) (BEDmin: +9.0 Gy [6.7-11.3 Gy], BEDmean: +1.4 Gy [0.8-2.1 Gy]). This benefit was smaller in larger tumors (-0.1%/10 cm³ PTV [-0.2 to -0.02%/10 cm³ PTV]) and ULT (-2.0% [-3.1 to -0.9%]). Occurrence of exceeded maximum doses inside the PTV (predicted: 21%, adapted: 4%) and violations of OAR constraints (predicted: 12%, adapted: 1%, OR: 0.14 [0.04-0.44]) was effectively reduced. OAR constraint violations almost exclusively occurred if the PTV had touched the corresponding OAR in the baseline plan (18/19, 95%).ConclusionAdaptive MRgSBRT is highly recommendable for ablative treatment of lung tumors whose PTV initially contacts a sensitive OAR, such as ULT. Here, plan adaptation protects the OAR while maintaining best-possible PTV coverage.

Dataset Information

Stereotactic ablative radiotherapy for ultra-central lung tumors: prioritize target coverage or organs at risk?

Publications

Stereotactic ablative radiotherapy for ultra-central lung tumors: prioritize target coverage or organs at risk?

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets