Eileen M Harder1, Henry S Park2, Zhe Jay Chen2, Roy H Decker2. 1. Department of Therapeutic Radiology, Yale University School of Medicine, Yale Cancer Center, New Haven, Connecticut. Electronic address: eileen.harder@yale.edu. 2. Department of Therapeutic Radiology, Yale University School of Medicine, Yale Cancer Center, New Haven, Connecticut.
Abstract
PURPOSE: Radiation pneumonitis (RP) may be severe after stereotactic body radiation therapy. Our purpose was to identify pulmonary and cardiac dosimetric parameters that predicted for post-stereotactic body radiation therapy grade ≥2 RP. METHODS AND MATERIALS: A total of 335 patients with ≥3 months' follow-up were included. Normal pulmonary volume was total lungs minus gross tumor volume. Pulmonary maximum dose, mean lung dose (MLD), and the percent of lung receiving ≥x Gy for 5 to 50 Gy in 5-Gy increments were collected. Cardiac maximum dose, mean dose, volume of lung receiving ≥0.1 Gy (V0.1), V0.25 to V1, and V2.5 to V12.5 were recorded. Multivariable logistic regression with manual backward stepwise elimination was used to identify the best dosimetric predictors of toxicity. Optimal dose-volume cutoffs were isolated with recursive partitioning analysis (RPA). RESULTS: The grade ≥2 RP rate was 18.8%. Pulmonary V5 to V50, MLD, and cardiac V0.1 to V2.5 were significantly associated with toxicity on univariate analysis. On multivariable logistic regression, V10 was the strongest dosimetric predictor of grade ≥2 RP (odds ratio, 1.052; 95% confidence interval, 1.014-1.092; P = .007). RPA identified a 21.6% risk of grade ≥2 RP with V10 ≥6.14% (vs 3.8% with <6.14). MLD was the most significant predictor of grade ≥3 RP (odds ratio, 1.002; 95% confidence interval, 1.000-1.003; P = .031). RPA identified a 25.0% risk of grade ≥3 RP with MLD ≥7.84 Gy (vs 8.0% when <7.84 Gy). CONCLUSIONS: With a grade ≥2 RP rate of 18.8%, lung V10 was the best predictor of grade ≥2 toxicity. MLD was the best predictor of grade ≥3 RP.
PURPOSE: Radiation pneumonitis (RP) may be severe after stereotactic body radiation therapy. Our purpose was to identify pulmonary and cardiac dosimetric parameters that predicted for post-stereotactic body radiation therapy grade ≥2 RP. METHODS AND MATERIALS: A total of 335 patients with ≥3 months' follow-up were included. Normal pulmonary volume was total lungs minus gross tumor volume. Pulmonary maximum dose, mean lung dose (MLD), and the percent of lung receiving ≥x Gy for 5 to 50 Gy in 5-Gy increments were collected. Cardiac maximum dose, mean dose, volume of lung receiving ≥0.1 Gy (V0.1), V0.25 to V1, and V2.5 to V12.5 were recorded. Multivariable logistic regression with manual backward stepwise elimination was used to identify the best dosimetric predictors of toxicity. Optimal dose-volume cutoffs were isolated with recursive partitioning analysis (RPA). RESULTS: The grade ≥2 RP rate was 18.8%. Pulmonary V5 to V50, MLD, and cardiac V0.1 to V2.5 were significantly associated with toxicity on univariate analysis. On multivariable logistic regression, V10 was the strongest dosimetric predictor of grade ≥2 RP (odds ratio, 1.052; 95% confidence interval, 1.014-1.092; P = .007). RPA identified a 21.6% risk of grade ≥2 RP with V10 ≥6.14% (vs 3.8% with <6.14). MLD was the most significant predictor of grade ≥3 RP (odds ratio, 1.002; 95% confidence interval, 1.000-1.003; P = .031). RPA identified a 25.0% risk of grade ≥3 RP with MLD ≥7.84 Gy (vs 8.0% when <7.84 Gy). CONCLUSIONS: With a grade ≥2 RP rate of 18.8%, lung V10 was the best predictor of grade ≥2 toxicity. MLD was the best predictor of grade ≥3 RP.
Authors: Christopher H Chapman; Christopher McGuinness; Alexander R Gottschalk; Sue S Yom; Adam A Garsa; Mekhail Anwar; Steve E Braunstein; Atchar Sudhyadhom; Paul Keall; Martina Descovich Journal: J Appl Clin Med Phys Date: 2018-04-26 Impact factor: 2.102
Authors: Noah S Kalman; Geoffrey D Hugo; Jenna M Kahn; Sherry S Zhao; Nuzhat Jan; Rebecca N Mahon; Elisabeth Weiss Journal: Adv Radiat Oncol Date: 2018-05-25