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Congying Xie
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P2.01 - Advanced NSCLC (ID 618)
- Event: WCLC 2017
- Type: Poster Session with Presenters Present
- Track: Advanced NSCLC
- Presentations: 1
- Moderators:
- Coordinates: 10/17/2017, 09:00 - 16:00, Exhibit Hall (Hall B + C)
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P2.01-071 - Efficacy of Thoracic Radiotherapy in Oligometastatic Non-Small-Cell Lung Cancer Harboring Wild-Type EGFR After First-Line Chemotherapy (ID 9650)
09:00 - 16:00 | Presenting Author(s): Congying Xie
- Abstract
Background:
Evidence from retrospective and small prospective trials suggested that local therapy might be beneficial for patients with oligometastatic non-small-cell lung cancer (NSCLC). The purpose of this study is to analyze the efficacy of thoracic radiotherapy in oligometastatic NSCLC patients harboring wild-type EGFR that did not progress after first-line chemotherapy in Asian population.
Method:
We retrospectively reviewed 181 stage IV NSCLC patients harboring wild-type EGFR with three or fewer metastatic lesions after first-line chemotherapy with an Eastern Cooperative Oncology Group(ECOG) performance status(PS) score of 2 or less. All the patients treated with first-line therapy of four to six cycles of platinum doublet therapy and did not progress. Patients were classified into two regimens: 89 patients received thoracic radiotherapy (arm A) with volumetric modulated arc therapy (VMAT) technology, 92 patients received maintenance treatment or observation only (arm B). Maintenance treatment used only one chemotherapy drug including gemcitabine or pemetrexed or docetaxel, and observation was defined as close surveillance without cytotoxic treatment. The progression-free survival (PFS) was defined as the interval from the date of treatment to the earliest date of disease progression or death. The overall survival (OS) was defined as the interval from the date of treatment to the date of death. PFS and OS were estimated by the Kaplan-Meier method and were compared by the log-rank test.
Result:
The median PFS of the thoracic radiotherapy arm was significantly longer than that of the maintenance treatment arm (7.5 vs. 4.3 months, p = 0.006). The median OS of the thoracic radiotherapy arm also slightly longer than that of maintenance treatment or observation arm (13.0 vs. 10.0 months, p=0.031). Multivariate analysis indicated that thoracic radiotherapy were independent predictors of PFS. Thoracic radiotherapy, ECOG PS (0-1) ,histology adenocarcinoma and no brain metastasis were correlated with longer OS.
Conclusion:
The thoracic radiotherapy could improve PFS and OS in oligometastatic unresectable NSCLC patients harboring wild-type EGFR that did not progress after first-line chemotherapy.
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P2.14 - Radiotherapy (ID 715)
- Event: WCLC 2017
- Type: Poster Session with Presenters Present
- Track: Radiotherapy
- Presentations: 2
- Moderators:
- Coordinates: 10/17/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)
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P2.14-008 - Partial and Full Arc VMAT in Lung Cancer SBRT with Different Definitions of Internal Target Volume Based on 4D CT (ID 9127)
09:30 - 16:00 | Author(s): Congying Xie
- Abstract
Background:
Three dimensional conformal radiation therapy (3DCRT) with 10-15 static fields is the most common technique used to create the desired conformal dose distribution for SBRT. The main drawback of 3DCRT planning is the lengthy treatment time relating to patient setup and radiation delivery resulted from many fields needed to create an acceptable treatment plan. The capability of VMAT to increase the sparing of organs at risk (OARs) without compromising conformal dose distributions in a shorter treatment time compared to IMRT and 3DCRT has been demonstrated for both conventional fractional radiotherapy and SBRT in the treatment of lung cancer. The purpose of this study is to investigate the feasibility of partial arc volumetric modulated arc therapy (VMAT) in lung cancer stereotactic body radiotherapy (SBRT), as well as the volumetric and dosimetric effects of different internal target volume (ITV) definitions with 4D CT.
Method:
Fourteen patients with primary and metastatic lung cancer underwent SBRT were enrolled in this study. Full and partial VMAT plans were generated with four different ITVs: ITVall, ITV~MIP~, ITV~AIP~ and ITV~2phases~, representing ITVs generated from all 10 respiratory phases, maximum intensity projection (MIP), average intensity projection (AIP), and 2 extreme respiratory phases. Volumetric and dosimetric differences, as well as MU and delivery time were investigated.
Result:
Full arc VMAT irradiated less dose 2 cm away from the PTV compared with partial arc VMAT (P=0.002), other than this, there was no significant difference on target coverage between partial and full arc VMAT plans. However, partial arc VMAT irradiated less MLD and V5 compared with full arc VMAT. Partial arc VMAT also achieved better protection on spinal cord, heart and esophagus compared with full arc VMAT. The average MU and delivery time of full arc VMAT plans were 240 and 1.6 min more than those of partial arc VMAT. No other significant difference was observed between these two planning schemes. There were no significant differences on target coverage and organ at risks (OARs) sparing among four ITVs. The average percent volume differences of ITV~MIP~, ITV~AIP~ and ITV~2phases~ to ITV~all~ were 8.6%, 13.4%, and 25.2%, respectively.
Conclusion:
Partial arc VMAT was feasible and more efficient for lung SBRT. Although ITV~MIP~, ITV~AIP~ and ITV~2phases~ were smaller than ITVall, no significant dosimetric differences resulted due to a relative small target volume of lung SBRT.
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P2.14-018 - Treatment Outcome and Lung Toxicities of Volumetric Modulated Arc Therapy in the Treatment of Inoperable Non-Small-Cell Lung Cancer Patients (ID 9140)
09:30 - 16:00 | Presenting Author(s): Congying Xie
- Abstract
Background:
Volumetric-modulated arc therapy (VMAT) has demonstrated the ability to deliver radiation dose precisely and accurately with a shorter delivery time and less MU compared to conventional intensity-modulated fixed-field treatment (IMRT) in the treatment of inoperable non–small-cell lung cancer (NSCLC). However, published data on clinical outcome and lung toxicities of VMAT in the treatment of NSCLC are scarce. The purpose of the present retrospective cohort study was to evaluate clinical outcome, acute and late pulmonary toxicities using VMAT (sequential/concurrent chemo) radiotherapy in inoperable NSCLC.
Method:
The clinical outcome, acute and late pulmonary toxicities of 134 consecutive inoperable NSCLC patients treated by VMAT with or without concurrent chemotherapy were retrospectively reviewed. Univariate and multivariate analysis on the dosimetric and characteristic factors associated with acute radiation pnuemonitis (RP) and pulmonary fibrosis were evaluated.
Result:
The average prescriptions dose to these patients were 5736.38±649.11 cGy (range from 5200 to 6400 cGy) with a median follow-up of 18.6 months (range, 2–45 months) for the enrolled 134 patients. The two-year progression-free survival (PFS) and overall survival (OS) for all patients was 18.2% and 38.4% with a median PFS and OS of 7.6 months and 18.6 months, respectively. There were 14 and 12 out of 134 patients experienced grade III/higher RP (10.45%) and pulmonary fibrosis (8.95%), respectively. Age, chemotherapy exposure, dose prescription, V10, V13, V20 and V30 were significantly associated with acute RP. Dose prescription was related to pulmonary fibrosis. Only V13 (p=0.02) and age (p=0.02) were independently associated with acute RP according to multivariate analysis. Based on regression analysis, the threshold for lung dosimetric metrics V10,V13,V20 andV30 were 50%,40%,28% and 18% in VMAT treatment of NSCLC to limit the RP rate <10%.
Conclusion:
VMAT can be delivered safely with acceptable acute and late toxicities for NSCLC. Lung dosimetric metrics were valuable in predicting acute RP. A threshold of 40% of Lung V13 in VMAT treatment of NSCLC was helpful to limit the RP rate <10%.
