Preoperative Positron-Emission Tomography May Be Beneficial in Reducing the Number of Unnecessary Surgeries in Patients With Lung Cancer
In patients with non–small cell lung cancer (NSCLC), preoperative positron-emission tomography (PET) has been shown to limit the number of unnecessary surgeries, according to the results of a study presented by Zeliadt et al in the Journal of Nuclear Medicine. Besides its value in accurate staging of NSCLC, preoperative PET may assist in clarifying regional lymph node status.
Recent studies have suggested that preoperative PET is effective in reducing the number of unnecessary surgeries in patients with NSCLC compared with conventional staging. However, few studies have been conducted to measure the real-world effectiveness of preoperative PET.
Study Details
Researchers associated with the Department of Veterans Affairs Medical Center in Seattle, undertook an evaluation of newly diagnosed patients with NSCLC who underwent preoperative PET. Their aim was to determine the value of preoperative PET in preventing unnecessary surgeries and improving patient outcomes in community practice. The researchers suspected that PET may have been performed selectively on the basis of unobserved characteristics; to reduce the influence of this potential bias, an instrumental variable analysis (with calendar time as the instrument) was conducted in addition to conventional multivariate logistic regression.
The investigators analyzed the medical records of 2,977 veterans with NSCLC who were treated at the Department of Veterans Affairs Northwest Health Network from 1997 to 2009. The majority of patients were male and were classified as either current (58.3%) or former (36.1%) smokers. Almost 33% of these patients had surgery; of these, almost 57% underwent preoperative PET.
Patients were determined to have undergone unnecessary surgery if pathology records showed evidence of extranodal lymph node involvement or metastasis or if the patients died within 12 months of surgery. The primary focus of this study was placed on patients who had stage IV disease.
Results
The percentage of patients receiving preoperative PET increased markedly over the course of the study, with 6% of newly diagnosed patients undergoing PET in the earlier years vs 61% in the later study years. Among all newly diagnosed patients, 32.8% went on to surgery; of these, 56.3% had received preoperative PET.
Overall, 54% of all patients and 20.6% of patients who underwent resection died within 12 months of diagnosis. Approximately 30% of patients showed evidence of metastasis within 12 months of surgery and were therefore deemed to have undergone unnecessary surgery.
Receipt of preoperative PET was not associated with a difference in the likelihood of unnecessary surgery on conventional multivariate analyses. However, on instrumental variable analysis, patients who received preoperative PET were found to be protected against the likelihood of unnecessary surgery (odds ratio [OR] = 0.53; 95% confidence index [CI] = 0.34–0.82; P = .004).
Using an adjusted risk differences approach, it was estimated that 38.2% of patients undergoing lung resection would have received surgery unnecessarily if preoperative PET had not been available. Thus, “the observed rate of 30.3% reflects a substantial improvement in patient outcomes,” the authors wrote.
Clinical Implications
The results from this study affirm the utility of preoperative PET, which is now universal in most cancer centers treating patients with non–small cell lung cancer, with 91.2% of patients who undergo lung resection receiving preoperative PET. The investigators noted that the reduction in unnecessary surgery associated with receipt of PET identified on instrumental variable analysis suggests that selection bias may have been common when PET first began to be offered.
Study author Steven B. Zeliadt, MD, of the Health Services Research and Development, Department of Veterans Affairs Medical Center, Seattle, remarked in a recent press release, “The prevailing evidence reinforces the general understanding within the medical community that positron-emission tomography is very useful for identifying occult metastasis and that it helps to get the right people to surgery while avoiding unnecessary surgeries for those who would not benefit.”
Dr. Zeliadt is the corresponding author of the article in the Journal of Nuclear Medicine.
This work is supported by the National Cancer Institute, the VA Puget Sound Health Care System, Seattle, Washington, the Department of Veterans Affairs, and the Portland VA Medical Center, Portland, Oregon.
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