Prediction of local tumor control and recurrence-free survival in patients with pancreatic cancer undergoing curative resection after neoadjuvant chemoradiotherapy

Background and objectives: There is little data on the correlation between the reduction in fluorodeoxyglucose positron emission tomography (FDG-PET) radioactive accumulation and carbohydrate antigen 19-9 (CA19-9) levels with pathological tumor responses (PTRs) and prognosis after neoadjuvant chemoradiotherapy (NACRT) for patients with pancreatic ductal adenocarcinoma (PDAC).

Methods: This study was a retrospective analysis of prospectively collected data from 102 patients with resectable (R-) and borderline resectable (BR-) PDAC who received NACRT, followed by curative resection. Data were prospectively collected and compared between the responders and nonresponders to NACRT.

Results: Patients with 60% or more reduction in maximum standardized uptake value (SUVmax) on FDG-PET, with 75% or more reduction in CA19-9 levels, or with 50%-100% of tumor cells destroyed due to NACRT had significantly better recurrence-free survival (RFS) than each of the nonresponders (p = 0.028, <0.001, and 0.022, respectively). The reduction rates of SUVmax and CA19-9 levels were correlated with PTR. The combined evaluation of these biomarkers reflected RFS.

Conclusions: Reduction rates of FDG uptake and CA19-9 levels were preoperative predictors of pathological response to NACRT. These biomarkers of local response had prognostic value in R-PDAC and BR-PDAC. The combined evaluation of these biomarkers allowed for reliable prediction of RFS after surgery.