PV QA 4 - Poster Viewing Q&A 4
Purpose/Objective(s): High-level evidence from randomized prospective studies is not available to guide multi-disciplinary management for early stage non-small cell lung cancer (NSCLC) patients. This is particularly important with increasing adoption of minimally invasive technologies including Video Assisted Thorascopic Surgery (VATS) and Stereotactic Body Radiation Therapy (SBRT). As increasing numbers of early-stage NSCLC are diagnosed through the Veterans Affairs (VA) Lung Cancer Screening Initiative, the current data are presented to examine and report our institutional experience in providing either treatment modality to our Veteran patients.
Materials/Methods: Electronic medical records were reviewed for a total of 187 consecutive patients discussed at Multidisciplinary Tumor Board with T1N0 or T2N0 NSCLC. Patients were primarily recommended for VATS lobectomy (n=148) and high-risk surgical candidates or patients refused VATS were treated with SBRT (n=39). SBRT was delivered to 51±4 Gy in 6±2 fractions (Biologically Effective Dose, BED=112±18 Gy) using IMRT and VMAT with 4D-CT to create integrated target volumes (ITV) to account for respiratory motion as needed. Patients were followed for recurrence with serial CT and or PET-CT every 3-6 months, with similar median follow-up between groups, (VATS=27, SBRT=25 mo). Patient characteristics are reported as median ± standard error and were tested by unpaired t-tests. Unadjusted Kaplan-Meier analyses were used for overall survival (OS), and local-control (LC) was calculated using Cox Proportional Hazards and reported as hazard ratio and 95% confidence interval (HR, 95%CI).
Results: VATS patients were younger (VATS=68 vs. SBRT=71y, P=0.03), and almost all were male. Median OS was longer for VATS vs. SBRT (27±11 vs. 22±8 months, p=0.02), with an improved overall hazard ratio, (HR=0.86, 95% CI=0.71-1.63, P=0.03). At one and three years, OS for VATS was 91±2% and 74±4%, longer than corresponding OS for SBRT, 83±6% and 60±10%). Unadjusted LC was not different between groups (not reported), and was improved with SBRT when controlled for tumor (T1 vs. T2), reflected at one and three years (VATS 98±2 and 84±5% vs. SBRT 97±3 and 78±7%), and with an improved overall hazard ratio (HR=0.9, 95% CI=0.7-2.3, P=0.04).
Conclusion: Despite higher pre-treatment co-morbidities that precluded VATS lobectomy for patients with early stage NSCLC, our single-institution retrospective analyses demonstrate non-surgical candidates treated with SBRT to have rates of disease control equal or better than VATS patients with similar survival outcomes. We await data from large-scale randomized controlled studies to validate our preliminary findings.
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