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P1.03 - Poster Session/ Treatment of Locoregional Disease – NSCLC (ID 212)
- Event: WCLC 2015
- Type: Poster
- Track: Treatment of Locoregional Disease – NSCLC
- Presentations: 1
- Coordinates: 9/07/2015, 09:30 - 17:00, Exhibit Hall (Hall B+C)
P1.03-016 - Clinical Outcome of Hybrid-Volumetric Arc Therapy (H-VMAT) for Advanced Inoperable Non-Small Cell Lung Cancer (NSCLC) (ID 1567)
09:30 - 17:00 | Author(s): L.L.K. Chan
H-VMAT is a mix of rotational arcs and static beams. Our previous published planning study indicates that H-VMAT is superior in dosimetric outcomes: improved conformity with better sparing of lung and spinal cord, compared to VMAT alone or conformal radiotherapy (CRT). While there are many planning studies, reports on clinical outcomes in IMRT especially VMAT for NSCLC are relatively sparse.
This retrospective study included inoperable stage IIA-IIIB NSCLC patients treated with H-VMAT or IMRT between late 2009 and 2013. Patients underwent simulation using 4D-CT. PET-CT data were fused with simulation images to enhance target delineation. H-VMAT composing of 2 hemi-arcs plus 2 static fields or 5-9 fields IMRT technique was used. Precision of treatment delivery was ensured by on-board kilovoltage imaging, mainly cone-beam CT. Survival outcomes, dosimetric data, patient characteristics and complication profiles were analysed.
A total of 71 patients were included. Patients characteristics and dosimetric parameters were tabulated in table one. The median follow-up was 2.5 years for alive subjects. The median prescribed dose was 60Gy. Three patients did not complete the planned treatment. The estimated 5-year overall survival (OS) was 19.2% (Figure 1a). Patients receiving sequential chemotherapy or chemo-radiotherapy fared much better than RT alone (Figure 1b). The 3-year disease-free survival was 12.7% in RT alone group and 17.0% in chemo-radiotherapy group. Two grade 3 esophagitis and three ≥grade 3 radiation pneumonitis were noted. Two treatment death were considered related to radiation pneumonitis, with superimposed chest infection. Compared to an unmatched historic cohort treated in 2004-08 using CRT, a trend of improvement in OS was observed (Figure 1c). Multivariate analysis demonstrated that GTV-volume and use of chemotherapy were important predictors in OS (both p <0.01).
Patient demographics and dosimetric data (n=71)Figure 1
Age median (range) 68 (34-89) Gender male: female 52: 19 Histology Adenocarcinoma 29 Squamous cell carcinoma 22 Not otherwise specified 15 Others 5 PET-CT Staging 65(91.5%) Group Stage (7th Ed.) IIA 3 (4.2%) IIB 9 (12.7%) IIIA 46 (64.8%) IIIB 13 (18.3%) RT Technique H-VMAT/ IMRT 60/ 11 Chemotherapy With vs. Without 43 : 28 PTV D~mean~ median/ Gray (range) 62.2 (61.2-77.3) GTV volume median/ cc (range) 91.3 (12.6-312.2) PTV volume median/ cc (range) 359.6 (99.5-1070.5) V20 (Lung-CTV) median/ % (range) 22.8 (3.7-34.9) Max Cord Dose median/ Gray (range) 41.3 (14.8-44.8)
H-VMAT/ IMRT together with chemotherapy resulted in favourable OS and low incidence of esophageal and pulmonary toxicities.
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