Recurrence patterns and surveillance strategies in long-term survivors of resected pancreatic cancer.

Abstract

e16361 Background: Pancreatic ductal adenocarcinoma (PDA) is the third leading cause of cancer-related mortality in the United States. After resection, the 2-year disease-free survival is < 50%. Surveillance guidelines after resection vary significantly between expert groups. The level of evidence is particularly weak for patients who are alive and disease-free after 2 years. Our objective was to report rates and predictors of recurrence in this population. Methods: We reviewed all patients who underwent resection of stage I-III PDA at Columbia University Irving Medical Center from 2011-2022. Eligibility criteria included patients who were alive and disease-free at 2 years after diagnosis. Demographic, surgical, and treatment characteristics were recorded. Imaging studies and tumor markers were reviewed and median time between studies after 2 years of follow up was determined. Recurrence was confirmed histologically or radiologically. Follow up and survival times were calculated using Kaplan Meier statistics. Associations between patient characteristics and recurrence risk were evaluated using a Cox proportional-hazards regression adjusted for demographic and treatment characteristics. Results: We reviewed 743 patients and 225 met eligibility criteria. The median age at diagnosis was 67.5 years. Median interval between surveillance imaging was 59 days and median interval between CA 19-9 draws was 41 days. After a median follow-up of 5.2 years from diagnosis, 84/225 (37%) patients experienced a late recurrence. Of these, 35% (29/84) had local recurrence, and 65% (55/84) had distant recurrence. The most common distant sites were lung (51%) and liver (27%). Lymph node positivity at resection was associated with late recurrence risk (p = 6x10-6), but T-stage (p = 0.5), margins (p = 0.9), age (p = 0.2) and chemotherapy receipt (p = 0.3) were not. Of the 72 patients with CA 19-9-producing tumors (baseline CA 19-9 > 37 U/mL) and complete normalization of CA 19-9 postoperatively, 30 patients had recurrence with CA 19-9 checked in the 9 months preceding recurrence. CA 19-9 re-elevation preceded recurrence in 83% (25/30) of late recurrences. Median time from CA 19-9 elevation to confirmation of recurrence was 5 months. Conclusions: The rate of recurrence for patients with PDA who are disease-free 2 years after diagnosis is lower than that for patients in their first 2 years. The most common sites of late recurrence are local and lung. For long-term PDA survivors with CA 19-9 producing tumors, serial CA 19-9 monitoring may be used to guide imaging. Positive lymph nodes at resection identify patients who are at highest risk for late recurrence.