Tailoring Adjuvant Chemotherapy to Biologic Response Following Neoadjuvant Chemotherapy Impacts Overall Survival in Pancreatic Cancer.

BACKGROUND: The role of postoperative chemotherapy in patients with resected pancreatic cancer who receive neoadjuvant treatment is unknown. Clinicians use changes in CA19-9 and histopathologic scores to assess treatment response. We sought to investigate if CA19-9 normalization in response to NAT can help guide the need for postoperative treatment. METHODS: Patients with elevated baseline CA19-9 (CA19-9 > 37U/mL) who received NAT followed by surgery between 2011 and 2019 were retrospectively reviewed. Treatment response was determined by CA19-9 normalization following NAT and histopathologic scoring. The role of postoperative chemotherapy was analyzed in light of CA19-9 normalization and histopathologic response. RESULTS: We identified and included 345 patients. Following NAT, CA19-9 normalization was observed in 125 patients (36.2%). CA19-9 normalization was associated with a favorable histopathologic response (41.6% vs 23.2%, p < 0.001) and a lower ypT (p < 0.001) and ypN stage (p = 0.003). Receipt of adjuvant chemotherapy was associated with improved overall survival in patients in whom CA19-9 did not normalize following NAT (26.8 vs 16.4 months, p = 0.008). In patients who received 5FU-based NAT and in whom CA19-9 did not normalize, receipt of 5FU-based adjuvant chemotherapy was associated with improved OS (p = 0.014). CONCLUSION: CA19-9 normalization in response to NAT was associated with favorable outcomes and can serve as a biomarker for treatment response. In patients where CA19-9 did not normalize, receipt of postoperative chemotherapy was associated with improved OS. These patients also benefited from additional 5FU-based postoperative chemotherapy following 5FU-based NAT.

Impact of Margin Status on Survival in Patients with Pancreatic Ductal Adenocarcinoma Receiving Neoadjuvant Chemotherapy.

BACKGROUND: Historically, a positive margin after pancreatectomy for pancreatic ductal adenocarcinoma (PDAC) was associated with decreased survival. In an era when neoadjuvant chemotherapy (NAC) is being used frequently, the prognostic significance of margin status is unclear. STUDY DESIGN: Patients with localized PDAC who received NAC and underwent pancreatectomy from 2011 to 2018 were identified from a single-institution database. Patients with fewer than 2 months of NAC, R2 resection, or fewer than 90 days of follow-up were excluded. A positive margin included tumors within 1 mm of the surgical margin. RESULTS: Four hundred and sixty-eight patients met inclusion criteria. Median age was 65 years and 53% were female. Preoperative clinical staging demonstrated that most had locally advanced (n = 222 [47%]) or borderline resectable (n = 172 [37%]) disease. Median follow-up was 18.5 months (interquartile range 10.6 to 30.0 months). Median duration of NAC was 119 days (interquartile range 87 to 168 days). FOLFIRINOX was first-line therapy for 67%, and 73% received neoadjuvant radiotherapy. Most underwent pancreaticoduodenectomy (69%). Forty percent were node-positive and 80% had an R0 resection. Fifty-six percent received at least 1 cycle of adjuvant therapy. Median overall survival and recurrence-free survival were 22.0 months (95% CI, 19.4 to 25.1 months) and 11.0 months (95% CI, 10.0 to 12.1 months). On multivariate analysis, margin status was not a significant predictor of overall survival or recurrence-free survival. Factors associated with overall survival included clinical stage, duration of NAC, nodal status, histopathologic treatment response score, and receipt of adjuvant chemotherapy. CONCLUSIONS: Microscopic margin positivity is not associated with recurrence and survival in localized PDAC patients resected after treatment with NAC. Aggressive surgical extirpation in high-volume centers should be considered in selected patients after extensive NAC.