Dataset Information

Dosimetric predictors of esophageal toxicity after stereotactic body radiotherapy for central lung tumors.

ABSTRACT:

Background and purpose

Stereotactic body radiotherapy (SBRT) to central lung tumors can cause esophageal toxicity, but little is known about the incidence or risk factors. We reviewed central lung SBRT patients to identify dosimetric factors predictive of esophageal toxicity.

Materials and methods

We assessed esophageal toxicity in 125 SBRT patients. Using biological equivalent doses with α/β=10 Gy (BED₁₀), dose-volume histogram variables for the esophagus (Dv and Vd) were assessed for correlation with grade ⩾2 acute toxicity.

Results

Incidence of grade ⩾2 acute toxicity was 12% (n=15). Highly significant logistic models were generated for D₅cc and Dmax (p<0.001). To keep the complication rate <20%, the model requires that D₅cc⩽26.3 BED₁₀. At 2 years, the probability of complication with BED₁₀D₅cc>14.4 Gy was 24%, compared to 1.6% if ⩽14.4 Gy.

Conclusions

This novel analysis provides guidelines to predict acute esophageal toxicity in lung SBRT. Dose to the hottest 5cc and Dmax of the esophagus were the best predictors of toxicity. Converting the BED₁₀ limits to physical doses, D₅cc to the esophagus should be kept less than 16.8, 18.1 and 19.0 Gy for 3, 4, and 5 fractions, respectively, to keep the acute toxicity rate <20%.

SUBMITTER: Wu AJ

PROVIDER: S-EPMC4254177 | biostudies-literature | 2014 Aug

REPOSITORIES: biostudies-literature

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Publications

Dosimetric predictors of esophageal toxicity after stereotactic body radiotherapy for central lung tumors.

Wu Abraham J AJ Williams Eric E Modh Ankit A Foster Amanda A Yorke Ellen E Rimner Andreas A Jackson Andrew A

Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology 20140723 2

<h4>Background and purpose</h4>Stereotactic body radiotherapy (SBRT) to central lung tumors can cause esophageal toxicity, but little is known about the incidence or risk factors. We reviewed central lung SBRT patients to identify dosimetric factors predictive of esophageal toxicity.<h4>Materials and methods</h4>We assessed esophageal toxicity in 125 SBRT patients. Using biological equivalent doses with α/β=10 Gy (BED₁₀), dose-volume histogram variables for the esophagus (Dv and Vd) were assesse ...[more]

PMID: 25064471

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Project description:PurposeStereotactic body radiation therapy (SBRT) in central lung tumors has been associated with higher rates of severe toxicity. We sought to evaluate toxicity and local control in a large cohort and to identify predictive dosimetric parameters.Methods and materialsWe identified patients who received SBRT for central tumors according to either of 2 definitions. Local failure (LF) was estimated using a competing risks model, and multivariate analysis (MVA) was used to assess factors associated with LF. We reviewed patient toxicity and applied Cox proportional hazard analysis and log-rank tests to assess whether dose-volume metrics of normal structures correlated with pulmonary toxicity.ResultsOne hundred twenty-five patients received SBRT for non-small cell lung cancer (n=103) or metastatic lesions (n=22), using intensity modulated radiation therapy. The most common dose was 45 Gy in 5 fractions. Median follow-up was 17.4 months. Incidence of toxicity ≥ grade 3 was 8.0%, including 5.6% pulmonary toxicity. Sixteen patients (12.8%) experienced esophageal toxicity ≥ grade 2, including 50% of patients in whom PTV overlapped the esophagus. There were 2 treatment-related deaths. Among patients receiving biologically effective dose (BED) ≥80 Gy (n=108), 2-year LF was 21%. On MVA, gross tumor volume (GTV) was significantly associated with LF. None of the studied dose-volume metrics of the lungs, heart, proximal bronchial tree (PBT), or 2 cm expansion of the PBT ("no-fly-zone" [NFZ]) correlated with pulmonary toxicity ≥grade 2. There were no differences in pulmonary toxicity between central tumors located inside the NFZ and those outside the NFZ but with planning target volume (PTV) intersecting the mediastinum.ConclusionsUsing moderate doses, SBRT for central lung tumors achieves acceptable local control with low rates of severe toxicity. Dosimetric analysis showed no significant correlation between dose to the lungs, heart, or NFZ and severe pulmonary toxicity. Esophageal toxicity may be an underappreciated risk, particularly when PTV overlaps the esophagus.

Dataset Information

Dosimetric predictors of esophageal toxicity after stereotactic body radiotherapy for central lung tumors.

Background and purpose

Materials and methods

Results

Conclusions

Publications

Dosimetric predictors of esophageal toxicity after stereotactic body radiotherapy for central lung tumors.

Similar Datasets

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