Adjuvant therapy in patients with resected pancreatic adenocarcinoma: Analysis of treatment patterns in a Canadian provincial institution.

Abstract

e16236 Background: In recent years adjuvant therapy (AT) options for pancreatic cancer have evolved. Compared to gemcitabine (Gem) alone, improved overall survival (OS) was demonstrated first in 2017 with gemcitabine and capecitabine (GemCap), and then further improved in 2018 with FOLFIRINOX. Given these options, we retrospectively reviewed the patterns of AT use in British Columbia (BC), Canada during these periods of availability of newer AT regimens. Methods: Patients (pts) treated at BC cancer centers between January 2017 to June 2018 (“GemCap era”), and July 2018 to December 2019 (“FOLFIRINOX era”), who had undergone curative intent resection and received at least one cycle of AT were included for chart review. Patient and disease characteristics, treatment details, and stated rationale for choice of AT regimen were collected. Analyses were performed with one-way ANOVA for comparison of means between regimens, and Chi-squared or Fisher Exact tests to determine correlation between clinicopathologic factors and likelihood of undergoing a given AT regimen. Results: 148 pts were identified: 67 treated in the GemCap era (Gem: 25, 37%, and GemCap: 42, 63%) and 81 treated in the FOLFIRINOX era (Gem: 26, 32%, GemCap: 20, 25%, FOLFIRINOX: 35, 43%). Examined variables included age, gender, ECOG, T and N stage, margins, lymphovascular invasion and post-operative CA19-9. In the GemCap era, use of GemCap vs. Gem was associated with younger average age (p = 0.001) and positive lymph node status (91% vs. 60%, p = 0.003). In the FOLFIRINOX era, use of Gem AT was associated with a delayed time from surgery to treatment (p = 0.045). AT assignment was not influenced by high volume vs low volume centre in the GemCap era. However, when not assigned treatment with FOLFIRINOX in the FOLFIRINOX era, pts were more likely to receive GemCap in low-volume centers, and more likely to recieve Gem in high-volume centers (p = 0.026). The most common stated reasons for choice of an inferior AT regimen were pt comorbidities or functional status (GemCap era: 24% and FOLFIRINOX era: 35%). In total, 40% of patients treated with GemCap and 49% of patients treated with FOLFIRINOX did not complete the intended treatment, with regimen-specific toxicity accounting for 32% (GemCap) and 29% (FOLFIRINOX) of incomplete treatment. Conclusions: With improvements in survival with newer AT regimens, the majority of pts in our real-world setting were assigned the more efficacious AT regimen. Within the limits of a small sample size, significant pt or disease factors predictive of AT assignment were not identified aside from age and lymph node positivity in the GemCap era, and time from surgery to treatment in the FOLFIRINOX era. However, many pts were not able to complete planned AT due to toxicity. Efforts to optimize pt eligibility to improve FOLFIRINOX tolerability are warranted.