Background: In the Medicare-aged population, liver, ovarian and pancreatic cancers have an incidence of 34–73/100,000, are associated with high mortality, can often be associated with no or vague symptoms, and rely on multiple tests for diagnosis (dx). Our objective is to quantitate dx testing and time to a cancer dx in Medicare recipients. Methods: Pts with newly dx’d liver, ovarian or pancreatic cancers were identified in 100% fee-for-service (FFS) Medicare enrollment and claims data from 1 Oct 2017 - 31 Dec 2022. Dx test use was tracked for up to 24 months prior to dx; pts had to have ≥1 dx test within 60 days before the cancer dx date. Inclusion criteria also included ≥24 months of continuous enrollment in FFS Medicare prior to dx and qualification based on age ≥65. Exclusion criteria included prior cancer dx and Medicare Advantage enrollment. The start of dx workup was identified by looking back in time at the sequence of dx tests occurring before the cancer dx date and were separated by ≤60 days between consecutive tests. The earliest test in the sequence was deemed the first dx test. Index date was defined as the latest office visit date before the first dx test or date of the first dx test if no office visit met criteria. Dx tests (ie, biopsies, endoscopies, imaging, lab tests) were identified by billing/CPT codes. Dx workup duration from index to dx date and dx test types received were tracked. Results: Among 59,490 Medicare beneficiaries analyzed, mean age was 77.0 (SD 7.3), 60% were female, and 80% were non-Hispanic White. Median (25^th, 75^th percentile) days from index date to cancer dx was 56 (24, 109) for liver, 47 (20, 91) for ovary, and 43 (16, 89) for pancreas. Dx testing modalities utilized for each cancer type (Table) demonstrate high variability. The percentage of pts who underwent both CT and MRI to help establish a liver, ovarian and pancreatic cancer dx was 38.6%, 14.1% and 32.3%, respectively. While overall imaging use prior to dx was high, PET and PET-CT use was low (<1% PET; 1.7%–2.2% PET-CT). Conclusions: Multiple tests are utilized to establish a cancer dx in Medicare beneficiaries, including use of multiple imaging modalities in the same patient. 25% of pts required more than 89-109 days, depending on cancer type, to establish a dx. There may be opportunities to increase diagnostic efficiency and shorten time to cancer diagnosis in older individuals.

*Potential explanations for biopsies not being available in all pts include pts being labeled as having CA by radiology findings alone and lag times in claims data.