Positron emission tomography (PET) scans are often used in cancer patients for staging, restaging, and monitoring for treatment response. These scans are also often used to detect recurrence in asymptomatic patients, despite a lack of evidence demonstrating improved survival. We sought to evaluate utilization of PET for this purpose and relationships with survival for patients with lung and esophageal cancers.
Using national Surveillance, Epidemiology, and End Results (SEER) and Medicare-linked data, we identified incident patient cases from 2005 to 2009, with follow-up through 2011. We identified cohorts with primary lung (n = 97 152) and esophageal (n = 4446) cancers. Patient and tumor characteristics were used to calculate risk-adjusted two-year overall survival. Using Medicare claims, we examined PET utilization in person-years (to account for variable time in cohorts), excluding scans for staging and for follow-up of CT findings. We then stratified hospitals by quintiles of PET utilization for adjusted two-year survival analysis. All statistical tests were two-sided.
There was statistically significant variation in utilization of PET. Lowest vs 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) vs 0.97 (SD = 0.29) scans per person-year for esophageal cancer. Despite this, for those undergoing PET, lowest vs highest utilizing hospitals had an adjusted two-year survival of 29.0% (SD = 12.1%) vs 28.8% (SD = 7.2%) for lung cancer ( P = .66) and 28.4% (SD = 7.2%) vs 30.3% (SD = 5.9%) for esophageal cancer ( P = .55).
Despite statistically significant variation in use of PET to detect tumor recurrence, there was no association with improved two-year survival. These findings suggest possible overuse of PET for recurrence detection, which current Medicare policy would not appear to substantially affect.