Impact of 18F-FDG PET used after initial treatment of cancer: Comparison of the national oncologic PET registry 2006 and 2009 cohorts

Since 2006, the National Oncologic PET Registry has collected prospective data on 18F-FDG PET performed for cancer indications in Medicare beneficiaries under the coverage-withevidence- development (CED) policy of the Centers for Medicare & Medicaid Services. In April 2009, coverage for PET performed to inform the initial treatment strategy of most solid tumors was expanded by the Centers for Medicare & Medicaid Services, but they continued to require CED for subsequent treatment strategy evaluations for many cancers. Methods: For all years, we assessed National Oncologic PET Registry data for bladder, kidney, pancreas, prostate, stomach, small cell lung, uterine, and all other cancers that required CED. We compared clinical profiles and changes in intended management by interval (before or after April 2009, designated as the 2006 and 2009 cohorts) for PET scans performed for restaging or suspected recurrence (2006, n 5 30,911; 2009, n 5 54,747) or for chemotherapy monitoring (2006, n 5 10,234; 2009, n 5 15,611). Results: There were slight differences between time periods but little difference by cancer type or patient age within a time period. For restaging or suspected recurrence, comparing the 2006 and 2009 cohorts, total change in intended management for all cancer types was about 33% in those younger than 65 y and about 35% in those older than 65 y (range by cancer type, 31%-41%). The referring physician impression of disease extent (restaging) or prognosis (chemotherapy monitoring) after PET was similar between cohorts. In the 2009 cohort, PET for chemotherapy monitoring was associated with a 25% increase in plans to continue therapy and a complementary decline in plans to adjust therapy. The greatest management impact of PET was during chemotherapy monitoring in the 2009 cohort, where a post-PET prognosis judged to be worse than before PET was associated with a plan to discontinue that therapy in 90% and to change to a different therapy in 65%. Conclusion: Our data demonstrate a similar impact of PET on planned management of cancer patients before and after the 2009 expansion of coverage. These results strongly suggest it is unlikely that new useful information will be obtained by extending the coverage of certain cancer types and indications only under CED. Future research on advanced imaging in the management of patients with cancer should focus on optimal sequencing and frequency of PET and other imaging modalities.