Cancer generally takes years to evolve, and early diagnosis can prevent life-threatening cancer. Establishing a link between precancerous states and cancer is essential for effective screening and prevention. Esophageal adenocarcinoma (EAC) is an increasingly prevalent, poor-outcome cancer, and its presumed precursor, Barrett's esophagus (BE), characterized by intestinal metaplasia, is evident in only about half of cases. Here to test whether BE is a prerequisite to EAC, we integrated epidemiological and clinical characteristics in a prospective cohort of 3,100 patients with EAC for any evidence of BE (BE-positive and BE-negative) and compared genomic features using a subset of 710 patients with whole-genome sequencing and 87 patients (380 samples) with multiregional whole-exome sequencing. Demographic and genomic features typically associated with BE were observed across BE-positive and BE-negative EAC cases. Notably, molecular features consistent with early BE evolution were detected in both phenotypes. Advanced tumor stage was the only variable that corresponded with increased likelihood of BE-negative EAC, including in some patients with a previous BE diagnosis. Phylogenetic analyses revealed shared evolutionary trajectories, and spatial transcriptomic and proteomic analyses demonstrated intestinal metaplasia-associated lineage markers in both groups. These findings suggest a single pathway to EAC, with implications for early diagnosis and prevention strategies.