PET Does Not Improve Detection of Some Recurrent Cancers

March 2, 2016
Diagnostic Imaging Staff

PET imaging does not improve detection of some recurrent cancer in asymptomatic patients.

PET is not useful in detecting tumor recurrence among patients with lung cancer or esophageal cancer, and the imaging is overused, according to a study published in the Journal of the National Cancer Institute.

Researchers from the University of Michigan in Ann Arbor sought to evaluate if PET was an effective method for detecting recurrence of cancer among asymptomatic patients who had been treated for lung and esophageal cancers. They identified incident patient cases from 2005 to 2009, with follow-up through 2011. A total of 97,152 patients had primary lung cancer and 4,446 had esophageal cancer. The researchers calculated risk adjusted two-year overall survival. They then used Medicare claims to examine the use of PET in person-years. Scans for staging and follow-up of CT findings were not included in this group. Finally, the researchers stratified hospitals by how much PET was used.[[{"type":"media","view_mode":"media_crop","fid":"46418","attributes":{"alt":"Mark Healy, MD","class":"media-image media-image-right","id":"media_crop_6009056424537","media_crop_h":"0","media_crop_image_style":"-1","media_crop_instance":"5383","media_crop_rotate":"0","media_crop_scale_h":"0","media_crop_scale_w":"0","media_crop_w":"0","media_crop_x":"0","media_crop_y":"0","style":"float: right;","title":"Mark Healy, MD","typeof":"foaf:Image"}}]]

The results showed that many hospitals frequently used PET to evaluate for recurrence of disease, and there was a statistically significant variation in how often PET was used for these patient groups. “Lowest versus highest utilizing hospitals performed .05 (SD = 0.04) vs 0.70 (SD = 0.44) scans per person-year for lung cancer and 0.12 (SD = 0.06) versus 0.97 (SD = 0.29) scans per person-year for esophageal cancer,” the authors wrote. However, regardless of the number of PET images that were taken, both high- and low-use hospitals had similar results for two-year survival:

 Two-Year Survival in Lowest PET Use HospitalsTwo-Year Survival in Highest PET Use Hospitals
Lung cancer29.0%28.8%
Esophageal cancer28.4%30.3%

"PET scanning is a great technology and very effective, but using it in this way doesn't seem to make any difference for these cancers that have a relatively poor prognosis," coauthor Mark Healy, MD, surgical resident and research fellow at the University of Michigan Department of Surgery, and member of the Center for Health Outcomes and Policy, said in a release. "The appropriate use of PET scanning in follow-up care for lung and esophageal cancer is after findings on lower-cost imaging options."

The researchers concluded that PET is overused in an attempt to detect recurrence of lung or esophageal tumors, and there is no association between improved survival and PET use in these circumstances.

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