Background: Recent advances in pancreatic adenocarcinoma (PDAC) research unveiled that molecular subtypes reflect cancer prognosis and chemosensitivity. Here, we examined the possible use of genomic profiling of PDAC in the clinic by assessing retrospective clinical outcomes and treatment responsiveness based on genetic alterations. Methods: All patients treated for PDAC with Next-Generation Sequencing (NGS) data available between 2014 to 2020 at Northwell Health Cancer Institute were included in a retrospective analysis. Patients were subdivided into resectable and unresectable cancer. Genetic findings frequently reported in NGS were used to compare progression-free survival (PFS) and overall survival (OS) within subgroups. Survival probability was compared using Peto-Peto’s modified survival estimate followed by pairwise comparisons using Peto-Peto’s modified survival estimate. Family-wise error rate was adjusted using Benjamini & Hochberg method. Results: A total 115 patients were qualified for the evaluation. In all cases of PDAC, TP53 mutation (n = 89) was associated with poor OS compared to the wild-type TP53 gene (n = 19) (median OS 20.2 months, 95% CI 10.2 to 39.7, vs. 41.1 months, 95% CI 20.9 to 81.0, HR 1.98, p = 0.028). In unresectable PDAC, tumors with GATA6 amplification (n = 11) were associated with a significantly better OS over patients whose tumors harbored a TP53 mutation (n = 57) (median OS 22.9 months, 95% CI 9.6 to 54.5, vs. 10.0 months, 95% CI 4.2 to 23.8, HR 0.48, p = 0.048). Within the TP53 mutation group, FOLFIRINOX (n = 21) did not show improved OS compare to Gem/NabP (n = 30) (mean OS 13.8 months, 95% CI 6.8 to 28.2, vs. 8.5 months, 95% CI 4.17 to 17.4, HR 0.84, p = 0.25). Other genetic alterations were not associated with OS. There was no difference in PFS in all PDACs. Conclusions: Our retrospective analysis showed that genetic changes in TP53 and GATA6 were significantly associated with the clinical outcome for PDAC. Mutation of TP53 was associated with poor OS in general. However, in unresectable PDAC, GATA6 amplification was associated with better clinical outcome than tumors with TP53 mutation. In contrary to general belief, FOLFIRINOX did not result in better OS than Gem/NabP.