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P1.02 - Poster Session/ Treatment of Localized Disease – NSCLC (ID 209)
- Event: WCLC 2015
- Type: Poster
- Track: Treatment of Localized Disease - NSCLC
- Presentations: 1
- Coordinates: 9/07/2015, 09:30 - 17:00, Exhibit Hall (Hall B+C)
P1.02-035 - Radiographic Changes in Lung of Patients Treated with Stereotactic Ablative Body Radiation Therapy and the Dosimetric Correlations (ID 2807)
09:30 - 17:00 | Author(s): P. Kumar
To describe radiographic evidence of radiation pneumonitis (rRP) and fibrosis (rRF) and determine what dosimetric parameters correlate with rRP and rRF after stereotactic ablative radiation therapy (SABR) to the lung.
98 follow up CT scans from 32 patients treated by SABR were retrospectively reviewed for CT appearance of rRP and rRF determined by the Ikezoe (≤ 6 months) and Koenig (≥ 7 months) systems. The correlation of dosimetric parameters such as planning target volume (PTV) and the volume of lung receiving dose of radiation (V2.5, V5, V7, V10, V15, V20, V25, and V30) to rRP, rRF, and fibrotic volume (V~fibrosis~) were analyzed using Spearman’s rho.
The median follow up was 10 months (range 2 – 24 months). There was a 55% incidence of rRP and 59% incidence of rRF. The low dose parameters of V~2.5, ~V~5, ~V~7~, and V~10 ~(the volume of lung receiving more than 2.5, 5, 7, and 10 Gy of radiation, respectively) were correlated to the development of rRP (p < 0.05). There was only V~10 ~correlated statistic significantly to the incidence of rRF, with V~5~, V~7,~ and V~10~ trended towards significance. The median V~fibrosis~ was 119 cm with a range of 49 – 829 cm. The medians of the PTV and ITV were 52.6 cm and 12.6 cm~, ~respectively. The absolute fibrotic volume was correlated with the planning target volume (PTV), V~7 ~and V~10 ~(p < 0.05).
The development of rRP and rRF was associated with the volume of lung that received lower dose of radiation. The absolute fibrotic volume from SABR was correlated with PTV and the volume of lung receiving lower dose of radiation. This finding needs to be validated with more patients’ data and longer follow up.