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MINI 33 - Radiotherapy and Complications (ID 164)
- Event: WCLC 2015
- Type: Mini Oral
- Track: Treatment of Locoregional Disease – NSCLC
- Presentations: 1
MINI33.04 - Acute Radiation Pneumonitis in Lung Cancer Treated with Volumetric Modulated Arc Therapy (ID 2634)
18:30 - 20:00 | Author(s): L. Xu
Thoracic radiotherapy plays an important role in the treatment of lung cancer. However, the safety of thoracic radiotherapy delivery is restricted to the risk of radiation pneumonitis(RP), which is the major dose limiting toxicity for patients undergoing thoracic radiotherapy. Few studies to date have assessed risk factors associated with the development of RP in lung cancer patients treated with volumetric modulated arc therapy (VMAT). This study aimed to report the RP incidence and clinical and dosimetric risk factors associated with RP in lung cancer patients treated with VMAT at a single institution.
In this retrospective study, lung cancer patients treated with VMAT from 2013 through 2015 were reviewed. RP was graded according to Common Terminology Criteria for Adverse Events (CTCAE) version.4.0. Clinical factors and dosimetric parameters were evaluated using logistic multivariate regression for estimating the correlation with RP. The results were considered statistically significant when the p-value was<0.05.
Thoracic radiotherapy with VMAT was administered in 77 lung cancer patients. Of these patients, 58 were men and 19 were women, with a median age of 60 years (range 22-84 years); 25 patients received concurrent chemoradiotherapy, and the median radiation dose was 60Gy (range 45-64Gy). VMAT plans were performed with single arc in 9 patients, double in 55 patients, triple in 4 patients, and the mean (±SD) delivery time was 189.1s±42.0s. VMAT allowed us to respect most planning objectives on target volumes and organs at risk, for PTV V~95% ~= 96.8 ± 6.1%; for lung V~5~ = 41.3 ± 8.7%, V~10~ = 29.9 ± 7.1%, V~20~ = 20.9 ± 5.7%, mean dose=1150.9±277.6Gy. With regard to acute RP after thoracic radiotherapy, 10.4% were grade 1 (G1), 16.9% G2, 9.1% G3, 2.6% G5. The overall incidence rate of symptomatic RP (grade ≥ 2 by CTCAE) was 28.6% in the entire cohort. Based on the clinical data and dosimetric parameters analysis, factors predictive of symptomatic RP were lung volume receiving ≥10Gy (V~10~) [OR: 1.39, 95% CI 1.07–1.80, p=0.014], PS score[OR:5.44, 95% CI 1.29–23.08, p=0.021], concurrent chemotherapy[OR:3.85, 95% CI 1.07–13.86, p=0.039]and CRP changing level[OR:1.06, 95% CI 1.01–1.12, p=0.014].
VMAT, a novel technique, provides a viable option for the thoracic radiotherapy of lung cancer with acceptable toxicities. However, for patients with higher V~10~, poorer PS score, greater increasing level of CRP and undergoing concurrent chemotherapy, VAMT technique should be administrated with cautions. Several molecular biomarkers have been reported that correlated with the development of RP, which will be tested in our further analysis.