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I. Poon
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P2.08 - Poster Session/ Thymoma, Mesothelioma and Other Thoracic Malignancies (ID 225)
- Event: WCLC 2015
- Type: Poster
- Track: Thymoma, Mesothelioma and Other Thoracic Malignancies
- Presentations: 1
- Moderators:
- Coordinates: 9/08/2015, 09:30 - 17:00, Exhibit Hall (Hall B+C)
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P2.08-029 - Stereotactic Ablative Radiotherapy (SABR) for Pulmonary Oligometastases and Oligoprogression (ID 2882)
09:30 - 09:30 | Author(s): I. Poon
- Abstract
Background:
Use of SABR to treat pulmonary oligometastases, and more recently, oligoprogression to delay the need to change systemic therapy, is increasing despite no randomized evidence. This project reviews the outcomes of treating pulmonary metastases from a large single institution.
Methods:
From a prospective SABR database, 180 pulmonary metastases in 120 patients were treated between 11/2008 and 12/2013. Indications for SABR were: 1) oligometastases, where the goal was to irradiate all sites of disease, 2) oligoprogression, where the goal was to irradiate only those tumours which were progressing while a systemic therapy strategy was controlling all other tumours, and 3) dominant areas of progression, where the goal was to irradiate dominant tumours, even if other tumours were progressing, usually in patients with indolent disease not on systemic therapy. Doses of 48-52 Gy in 4-5 fractions were delivered as per institutional policy depending on tumour location and histology. Since 2010 the dose for peripheral colorectal cancer (CRC) metastases was increased to 60 Gy in 4 fractions after a preliminary analysis revealed a higher local failure rate in those tumours.
Results:
Median age of patients was 66.5 years. Median duration of follow-up was 21.1 months. Median biological effective dose (BED) was 120 Gy~10~. We observed 1 (<1%) grade 5, 1 (<1%) grade 3 and 8 (7%) grade 2 radiation pneumonitis. 2 year local control (LC) of irradiated tumours was 81%. Non-CRC metastases had higher 2 year LC compared to CRC tumours (94% vs 70%, p=0.002). In 18 patients with non small cell lung cancer (NSCLC) pulmonary metastases, 2 year LC was 95%. In the subgroup of 59 patients with CRC metastases, delivering 60 Gy was associated with significantly higher 2 year LC compared to lower doses (88% vs 61%, p=0.011). In 79 patients with oligometastases treated with SABR, the 2 year progression free probability (PFP), progression free survival (PFS) and overall survival (OS) were 63%, 42%, and 73%, respectively. In 27 patients with oligoprogression treated with SABR, the 2 year PFP, PFS, and OS were 42%, 24%, and 70%, respectively. At 2 years, no change in systemic therapy was seen in 56% of the patients irradiated for oligoprogression, with a median time to changing systemic therapy of 30.8 months. In the 12 oligoprogression patients where a change of systemic therapy strategy occurred after SABR, the median time to systemic therapy change was 8.3 months.
Conclusion:
CRC metastases require higher SABR doses to optimize their LC. Outcomes for patients with oligometastases and oligoprogression treated with SABR seem favourable, but prospective clinical trials are needed to confirm these benefits.
