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MO17 - Radiotherapy I: Stereotactic Ablative Body Radiotherapy (ID 106)
- Event: WCLC 2013
- Type: Mini Oral Abstract Session
- Track: Radiation Oncology + Radiotherapy
- Presentations: 1
MO17.01 - Response assessment of Stereotactic Ablative Body Radiotherapy (SABR) for pulmonary metastases: utility of 4D-FDG-PET and CT perfusion (ID 2225)
16:15 - 17:45 | Author(s): P. Antippa
Response assessment using conventional RECIST criteria after SABR of lung targets can be confounded by fibrotic response. The purpose of this study was to evaluate the utility of 4D-FDG-PET/CT and CT perfusion scans in the response assessment of single fraction SABR for inoperable pulmonary oligometastases.
This is a prospective ethics approved clinical study of patients undergoing single fraction SABR with 26Gy for pulmonary metastases. Eligible patients had 1-2 metastases with no extrathoracic disease on staging FDG-PET. Serial 3D / 4D-FDG-PET and CT perfusion studies were performed at baseline, 14 days and 70 days after therapy. Two radiologists independently reported CT perfusion scans.
At a median follow-up of 16 months (range 3-27), 10 patients with 13 metastases received SABR. A further 7 patients (41%) were screened from the study due to interval progression of disease between the time of the original FDG-PET and trial 4D-FDG-PET / perfusion CT. The mean time between the original FDG-PET and trial scans was 62 days. No patient progressed locally, 7/10 patients progressed distantly of which 2/7 received subsequent SABR. At the end of study period, 5/10 patients are alive without disease. The median progression free survival was 14 months. The change in SUVmax from baseline was higher on 3D than 4D-PET by a mean of 20.6% (range 0.2%-47.2%) at 14 days and 14.8% (range 0-37.8%) at 70 days. Overall, the SUVmax increased at 14 days (mean 104.9%, p<0.01) and decreased at 70 days (mean=55.5%, p<0.01), despite persistent morphological lesions on the concurrent late timepoint CT. There was strong level of inter-observer agreement of CT perfusion interpretation with a median intraclass correlation coefficient of 89% (range 57%-98%). Perfusion parameters of Time to Peak Blood Flow and Blood Volume showed a median increase of 18.8% and 23.0% at 2 weeks post-therapy and decreased below baseline by a median 7.0% and 14.0% at 70 days (non-significant).
High rates of interval progression between staging scans indicates a need to expedite management of oligometastases in a timely fashion. Increased tumour perfusion and FDG-PET intensity at 2 weeks post-RT is likely due to an inflammatory response to large single dose SABR. Late PET response was associated with tumour control despite CT apparent morphological lesions. Conventional 3D PET may overestimate change in PET intensity post SABR as compared to 4D PET. These findings, in particular CT perfusion findings, require a larger patient cohort for validation.
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P2.16 - Poster Session 2 - Other Thoracic Malignancies (ID 187)
- Event: WCLC 2013
- Type: Poster Session
- Track: Thymoma & Other Thoracic Malignancies
- Presentations: 1
- Coordinates: 10/29/2013, 09:30 - 16:30, Exhibit Hall, Ground Level
P2.16-003 - The efficacy of VATS versus open thoracotomy: a systematic review (ID 1867)
09:30 - 16:30 | Author(s): P. Antippa
VATS has become an increasingly popular technique for the cardiothoracic surgeon. Its use in the treatment of malignancy has been an issue of debate previously. Whilst its use has been documented for the treatment of primary lung cancers, its use in metastasectomy has been brought under question for several reasons. The low sensitivity of pre-operative CT in diagnosis of metastatic disease in the lungs, compared to palpation means that VATS may miss resection of metastatic lesions. VATS has also been associated with pleural and port site seeding. Whilst there have been several studies demonstrating roughly equivalent survival and more rapid post-operative recovery in minimally invasive approaches, there remains no randomised trials and other high level evidence regarding the oncological outcomes of VATS versus open thoracotomy for pulmonary metastases. This article attempts to provide a systematic review of studies which have directly compared open and VATS resection of pulmonary metastasis in terms of outcome.
The study followed the PRISMA protocol for systematic reviews and meta-analyses. The search strategy included an electronic literature review using the PubMed database. The MeSH terms utilised were pulmonary metastasectomy, VATS, thoracoscopic and open. The inclusion criteria for the studies are that they had to have 2 limbs for direct comparison of VATS and open thoracotomies. The studies should also provide data regarding overall survival data or recurrence free survival data separately for the 2 limbs of the study.
Nine studies with 777 patients fulfilled the inclusion criteria. The VATS groups had slightly higher odds of 1, 3 and 5 year survival with OR of 1.53, 1.69 and 1.41 respectively. All these results demonstrated no heterogeneity on testing. However, only 3 year survival was statistically significant for overall effect. The VATS group also had higher odds of 1, 3 and 5 year recurrence free survival with OR of 1.29, 1.54 and 1.54 respectively for each of these outcomes. Once again the tests demonstrated no significant heterogeneity on testing. None of the outcomes demonstrated statistical significance in testing for overall effect. Overall pulmonary recurrence had lower odds in the VATS group with an odds ratio of 0.55. This data was not significantly heterogenous (p = 0.15) and did not demonstrate statistical significance in testing for overall effect also (p = 0.28).
Outcomes from VATS are comparable to, if not better than, open thoracotomy. VATS is a suitable choice for pulmonary metastasectomy.