Author Contributions:Study concept and design: Swartz, Hughes, Yeo, Laheru, and Abrams. Acquisition of data: Swartz, Hughes, Riall, Lillemoe, and Abrams. Analysis and interpretation of data: Swartz, Hughes, Frassica, Herman, Cameron, Donehower, and Hruban. Drafting of the manuscript: Swartz and Hughes. Critical revision of the manuscript for important intellectual content: Swartz, Hughes, Frassica, Herman, Yeo, Riall, Lillemoe, Cameron, Donehower, Laheru, Hruban, and Abrams. Statistical analysis: Hughes. Administrative, technical, and material support: Swartz, Yeo, Lillemoe, Donehower, Laheru, and Hruban. Study supervision: Frassica, Herman, Cameron, and Laheru.