Predictive factors for acute radiation pneumonitis in postoperative intensity modulated radiation therapy and volumetric modulated arc therapy of esophageal cancer

Abstract

BackgroundRadiation pneumonitis (RP) is a common side reaction in radiotherapy for esophageal cancer. There are few reports about RP in esophageal cancer patients receiving postoperative intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT). This study aims to analyze clinical or dosimetric factors associated with RP, and provides data for radiotherapy planning.MethodsWe reviewed 68 postoperative esophageal cancer patients who were treated with radiotherapy at the West China Hospital from October 2010 to November 2012 to identify any correlation between the clinical or dosimetric parameters and acute radiation pneumonitis (ARP) or severe acute radiation pneumonitis (SARP) by t-test, chi-square test, and logistic regression analysis.ResultsOf the 68 patients, 33 patients (48.5%) developed ARP, 13 of which (19.1%) developed SARP. Of these 33 patients, 8 (11.8%), 12 (17.6%), 11 (16.2%), and 2 (2.9%) patients were grade 1, 2, 3, and 4 ARP, respectively. Univariate analysis showed that lung infection during radiotherapy, use of VMAT, mean lung dose (MLD), and dosimetric parameters (e.g. V20, V30) are significantly correlated with RP. Multivariate analysis found that lung infection during radiotherapy, MLD ≥ 12 Gy, and V30 ≥ 13% are significantly correlated with an increased risk of RP.ConclusionLung infection during radiotherapy and low radiation dose volume distribution were predictive factors associated with RP and should be accounted for during radiation planning.

Organ at risks sparing with simultaneous integrated boost volumetric modulated arc therapy for locally advanced non-small lung cancer: an automated treatment planning study

“…Patients with high lung V 30 (exceed 14.2%) suffered 2.92-fold increased risk of RP compared to those with low V 30 (no more than 14.2%). Other two studies also considered lung V 30 as an independent predictor for the occurrence of symptomatic RP [19,21]. In our study, the SIB-VMAT plans achieved a sharp reduction in lung V 30 , with median decreased proportion of 8.7%, which would benefit a lot in the reduction of lung toxicities.…”

Intensity-modulated versus 3-dimensional conformal radiotherapy in the definitive treatment of esophageal cancer: comparison of outcomes and acute toxicity

“…It remains an attractive modality largely owing to the intimate anatomic relationship of the esophagus with both lungs and the heart. Indeed, several publications have posited a positive correlation between radiation dose to the lungs [ 14 – 18 ] and heart [ 19 – 22 ], with the risk of toxicities in these structures. Hence, the high conformality of IMRT could theoretically afford fewer toxicities to these organs-at-risk (OARs), especially in the setting of relative dose-escalation with dCRT, but supportive data are currently lacking.…”

<p>Sparing Organs at Risk with Simultaneous Integrated Boost Volumetric Modulated Arc Therapy for Locally Advanced Non-Small Cell Lung Cancer: An Automatic Treatment Planning Study</p>

“…Another two studies also considered lung V 30 as an independent predictor for the occurrence of symptomatic RP. 24,26 In our study, the SIB-VMAT plans achieved a sharp reduction in lung V 30 , with median decreased proportion of 8.7%, which would benefit a lot in the reduction of lung toxicities. Xia et al 27 compared the SIB-IMRT with C-IMRT plans, and found that the SIB-IMRT plans got lower mean dose, V 5 and V 20 of total lung.…”