In the Journals

PET may be overused to detect lung, esophageal cancer recurrence

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February 22, 2016

The use of PET scanning to screen for tumor recurrence in lung and esophageal cancer survivors did not appear associated with an improvement in 2-year survival rates, according to the results of a retrospective study.

These findings suggest the potential overuse of PET scans for recurrence monitoring, according to the researchers.

“PET scanning is a great technology and is very effective, but using it in this way doesn’t seem to many any difference for these cancers that have a relatively poor prognosis,” Mark A. Healy, MD, surgical resident and research fellow at University of Michigan, said in a press release. “The appropriate use of PET scanning in follow-up care for lung and esophageal cancer is after findings on lower-cost imaging options.”

PET scanning is frequently used to detect recurrences in asymptomatic cancer survivors, despite a lack of evidence demonstrating OS improvements. In 2013, CMS limited routine reimbursement to three PET scans following initial treatment.

Thus, Healy and colleagues sought to evaluate how often PET is used to detect recurrence in lung and esophageal cancers and whether its use appeared associated with improved survival.

The researchers accessed SEER and Medicare-linked data to identify incident cases of lung and esophageal cancers from 2005 to 2009, with follow-up data available through 2011. They identified cohorts of patients with lung cancer (n = 97,152; median age, 76 years; 52% men) and esophageal cancers (n = 4,446; median age, 76 years; 73% men).

After excluding “appropriate” scans, or those for staging and follow-up of CT findings, the total mean number of PETs was 49,471 for lung cancer and 3,160 for esophageal cancer. The mean PET per patient was 0.51 for those with lung cancer and 0.71 for those with esophageal cancer.

When considering patients of all disease stages, 3.9% of those with lung cancer and 5.3% of those with esophageal cancer underwent more than three scans. This means 96.1% of patients with lung cancer and 94.7% of those with esophageal cancer would have been unaffected by the 2013 Medicare policy change, according to the researchers.

“Our work shows that almost no one is getting the three-scan limit set by Medicare,” Healy said. “But with many thousands of patients getting one or two scans across the whole country, this is still a very large number, with very high costs. If the intention of the policy is to curb overuse, this doesn’t seem to be a very effective method, and the agency should reevaluate how it structures its limits.”

Researchers also stratified hospitals by quintiles of PET use and observed significant variation in the use of PET scans.

The lowest-volume hospitals performed 0.05 (standard deviation [SD] = 0.04) scans per person-year for lung cancer, whereas the highest-volume hospitals performed 0.7 (SD = 0.44).

For esophageal cancer, the lowest-volume hospitals performed 0.12 (SD = 0.06) scans per person-year and the highest-volume hospitals performed 0.97 (SD = 0.29) scans.

However, these disparities in PET use did not affect 2-year survival across quintiles among patients who underwent PET. Researchers observed similar 2-year OS rates for lung cancer at low-volume hospitals (29%, SD = 12.1%) and high-volume hospitals (28.8%, SD = 7.2%) and for esophageal cancer at low-volume hospitals (28.4%, SD = 7.2%) and high-volume hospitals (30.3%, SD = 5.9%).

Further, 75% of hospitals with the highest use of PET scanning for esophageal cancer recurrence were in the same quintiles for lung cancer, suggesting that high-use hospitals remained high users across disease groups.

The researchers acknowledged limitations of their study, including their inability to detect asymptomatic patient status from Medicare claims data, as well as the potential for selection bias.

“Following evidence-based guidelines for clinical follow-up is the way to go,” Healy said. “Don’t order PET in asymptomatic patients. And for patients, if you are not having symptoms and you’re doing well, there’s no reason to seek out this scan.” – by Cameron Kelsall

Disclosure: Healy reports research funding from the NIH. Other researchers report grant support from the American Cancer Society, the Association for Healthcare Research and Quality, and GlaxoSmithKline, as well as speaking fees from Covidien Ltd.