2012 HSR&D/QUERI National Conference Abstract
1064 — A Comparative Effectiveness Study of Pre-Operative PET Imaging and the Reduction of Unnecessary Lung Cancer Surgery
Zeliadt SB, and Backhus LM, VA Puget Sound HCS; Kessler LG, University of Washington; Hu E, and Au DH, VA Puget Sound HCS;
Once imaging tests have been approved by the FDA to be safe and effective at producing high quality images, they rarely receive further evaluation in randomized trials on clinical outcomes. We conducted a comparative effectiveness study to assess whether pre-operative PET imaging has led to fewer patients with non-small cell lung cancer receiving unnecessary surgical resection.
We identified a cohort of Veterans in the Pacific Northwest Network (VISN20) using the regional tumor registry and data warehouse who were newly diagnosed with lung cancer and received a thoracotomy between 1997 and 2009. All positron emission tomography (PET) and other imaging tests and staging procedures were identified in the 180 days prior to surgery. We used the Fisher, et. al. definition of futile thoracotomy: positive ipsilateral or contralateral mediastinal lymph nodes, evidence of metastatic disease, or dying within 12 months of surgery. IV-probit was used to adjust for potential selection bias, as PET adoption was heterogeneous over the study period.
Pre-operative PET imaging was widely adopted over the study period, increasing from 9% in 1997 to 89% in 2009 (trend test p <0.001). There was a trend toward fewer patients receiving futile thoracotomy over the same period, from 29% to 22% (p = 0.110). Several factors were predictive of receiving PET, including younger age (p = 0.007) and not having COPD (p = 0.05), suggesting selection bias was present over the period in determining which patients received PET. The IV-probit model using calendar year as the instrument suggests the predicted probability of receiving futile throacotomy if a patient had a pre-operative PET was 36% (p = 0.032) lower compared to the probability of unnecessary surgery without a pre-operative PET.
In this natural experiment, PET imaging had a strong association with reduced risk of unnecessary surgery for lung cancer.
PET imaging is becoming the standard of care for non-small cell lung cancer evaluation and should be included in the pre-operative work up for all patients considering thoracotomy.