Background: Only 15-20% of pancreatic ductal adenocarcinoma (PDAC) patients are upfront surgical candidates at presentation, and for this cohort of patients, the 5-year survival is a mere 20% despite adjuvant therapy. Previous data indicate that in clinical practice most of these cases are "borderline-resectable," and there is currently no mature data on perioperative treatment.
Methods: We performed a retrospective electronic chart review of patients with "borderline-resectable"PDAC treated at an academic comprehensive cancer center, dividing them into groups based on surgery alone, surgery plus neoadjuvant, adjuvant, or neoadjuvant plus adjuvant perioperative treatment groups. The objectives were to determine the median overall survival (mOS), progression-free survival (PFS) and disease-free survival (DFS). Statistical analysis was performed to assess the association of demographic, tumor traits, and interventions with OS, PFS and DFS.
Results: Only surgery followed by adjuvant therapy showed an increase in mOS [hazard ratio (HR) 0.22; 95% CI, 0.09-0.51; P<0.001), after adjustment for radiation (yes vs. no), resection margins (R0 vs. R1 or R2), and tumor location (head vs. body or tail). Patients who received adjuvant therapy after surgery had 2.1 times greater odds to be alive at 24 months after diagnosis than those who had surgery alone (P=0.015). PFS and DFS were not statistically significantly different among treatment groups after adjustment. Those whose disease was located in the head of the pancreas had a significantly improved OS (HR =0.27; 95% CI, 0.11-0.64; P=0.003), PFS (HR =0.40; 95% CI, 0.17-0.94; P=0.035), and DFS (HR =0.30; 95% CI, 0.13-0.67; P=0.004). Negative margins led to a significant improvement in PFS (HR =0.30; 95% CI, 0.16-0.57; P<0.001) and DFS (HR =0.30; 95% CI, 0.16-0.57; P<0.001). Those who received radiation had a non-significantly improved OS, PFS, and DFS (P>0.05).
Conclusions: Our study corroborated that patients treated with adjuvant therapy after surgical resection had an mOS benefit as reported on prior phase III clinical trials. Patients with "borderline-resectable" pancreatic cancer are encouraged to participate in a clinical trial or clinically be treated with adjuvant therapy until more mature results from the ongoing perioperative prospective study are available.
Keywords: Borderline; adjuvant; cancer; neoadjuvant; pancreas; resectable; surgery.