Authors: Randi Zukas Carhart, Ida Micaily, Roberto Stefan Fratamico, Constantine Daskalakis, Sophia Lam, Steven J. Cohen, Atrayee Basu Mallick
Published: 2021-01-22
DOI: 10.1200/jco.2021.39.3_suppl.428
Source: Full article
428 Background: Pancreatic adenocarcinoma is the fourth most common cause of cancer-related death in the US. The location of the primary lesion has long been thought to influence survival due to differences in time to presentation and ability to undergo cancer directed surgery. We hypothesized that patients with tumors arising in the body or tail (distal) would have poorer survival than patients who presented with lesions in the head of the pancreas (proximal) and that this difference would be true regardless of stage at diagnosis due in part to other factors such as intrinsic differences in the biology of these tumor types. A retrospective chart review at a single center with a high volume of pancreatic cancer directed surgery was carried out to address this question. Methods: Institution database was queried to identify patients with the ICD9 diagnosis of pancreatic adenocarcinoma of the head, body, and tail between 2014-2017; the inclusion criteria were 18 years or older, biopsy proven adenocarcinoma and a single mass in the pancreas at presentation. A total of 907 entries were screened with 324 patients being analyzed (236 proximal and 88 distal). CDC National Death Index registry and obituary reports were utilized to determine official dates of death. Results: Overall median survival was statistically higher in the proximal group than the distal group 16.0 vs 11.2 months (p=0.015). However, there was no significant difference in survival by stage of the proximal group over the distal group with stage I/II in the proximal group surviving 21 months versus distal 25.7 months, p=0.436; stage III, proximal surviving 11.7 months versus distal 18.0 months, p=0.393; stage IV, proximal surviving 6.5 months versus distal 4.9 months, p=0.675. The distal group was more likely to be metastatic on diagnosis (59% versus 18%) and was less likely to undergo surgery (34% vs 50%). In the surgical group, there was similar survival of 24.6 months in the proximal group versus 19.4 distal (p=0.795). Conclusions: Patients in the proximal group had a higher overall survival than the distal group as expected. Overall, however, when broken down by stage or surgery, the difference in survival between the proximal and distal groups was minimal with Hazard Ratio 0.96 (95%, CI=0.7, 1.30). Therefore, early stage diagnosis or surgery strongly account for the survival benefit in the proximal population rather than other factors like an intrinsic difference in the nature of the tumors themselves.