Abstract A135: Optimizing the metrics: Following progress in PNET and PDAC treatments with histology, stage, and time-specific relative survival rates

The 5-year relative survival rate (RSR) for pancreatic cancer (PC) has risen from 4% in the mid-1990s to a recent estimate of 13.7%. The incidence of PC also increased during this time, and recently a sharp increase in the number of incidentally detected, well-differentiated pancreatic neuroendocrine tumors (PNET) has been noted. To better understand these trends, we analyzed the relative contributions of PC histologic subtypes to overall RSR with the goal of identifying the most meaningful metrics to separately track progress in PNET and pancreatic ductal adenocarcinoma (PDAC), the most common and most lethal subtype. Given the anticipated expansion of targeted therapies for PDAC, particularly in the metastatic setting, we also evaluated 1–5 year RSRs to determine the most appropriate metric for monitoring clinical progress as the standard of care improves.

Methods:

Incidence and 1-5 yr RSR for patients diagnosed in the US between 2000-2023 were determined using the Surveillance, Epidemiology and Endpoint Results (SEER)-17 database and SEER*Stat software. Contribution of histological subtypes to the overall 5 yr RSR was determined by weighted analysis (survival x incidence), normalized to 100% per year. Subgroups of cancer patients with a RSR of <50% represent a priority to focus research and development efforts.

Results:

Over the past 23 years, localized PNET diagnoses increased 21-fold. PNET now accounts for 49% of the overall 5 yr RSR for PC. Of all stages of PNET, only distant disease has a 5 yr RSR < 50% (35%, 2018 diagnosis cohort). By contrast, PDAC 5 yr RSR remains below 5% across all stages (localized 11%, regional 9%, distant 1%, 2018 diagnosis cohort). Analysis of 1-4 yr RSRs across PC histologic subtypes and stages revealed that the 2 yr RSR for all stages of PDAC (14%, 2021 diagnosis cohort) is a more responsive and timelier metric for capturing gains as we enter a new era of treatment.

Conclusion:

Although SEER-based analysis is a lagging indicator, it provides longitudinal population-level data to demonstrate the real-world impact of emerging targeted therapies for both PDAC and PNET. While the overall 5 yr RSR for PC remains important, two complementary metrics - 5 yr RSR for distant PNET and 2 yr RSR for PDAC (all stages) - offer additional granularity to monitor anticipated progress and guide prioritization of research and development efforts.

Citation Format:

Kawther Abdilleh, Kristina Harris, Lola Rahib, Julie Logston, Anna Berkenblit, Jordan Berlin, Lynn M. Matrisian. Optimizing the metrics: Following progress in PNET and PDAC treatments with histology, stage, and time-specific relative survival rates [abstract]. In: Proceedings of the AACR Conference on Pancreatic Cancer: New Frontiers in Biology and Therapeutic Development; 2026 Sep 25-28; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(18_Suppl_2):Abstract nr A135.