Discrepancy Between Radiographic and Pathological Response Assessment in Neoadjuvant Treatment for Pancreatic Cancer:...

Appropriate reassessment of treatment response plays a crucial role in identifying optimal candidates for resection in neoadjuvant treatment (NAT) strategy for pancreatic cancer (PC); however, radiological evaluations are associated with limitations such as discrepancies with pathological response. Radiotherapy can induce inflammatory responses, potentially leading to an overestimation of residual tumor viability. This study explored the relationship between radiographic and pathological response assessments in NAT, focusing on the difference between neoadjuvant chemotherapy (NAC) and neoadjuvant chemoradiotherapy (NACRT).

Patients with resectable, borderline resectable, and initially unresectable locally advanced PC who had undergone curative resection after NAT were included in this study. The correlation between radiological assessment using RECIST criteria and pathological response according to Evans classification in the NAC and NACRT groups was assessed.

No significant differences were observed between the groups in terms of the findings of the RECIST assessment; however, the rate of favorable pathologic response (Evans ≥ IIb) in the NACRT group was significantly higher (p < 0.001). Furthermore, a comparison between the Evans grade for each RECIST criteria revealed a higher favorable pathologic response rate in the NACRT group among patients categorized as "stable disease (SD)" (p < 0.001). Some patients receiving NACRT who were initially classified as SD exhibited pathological complete response (Evans IV).

Discrepancies between radiographic and pathological response assessments in NAT for PC may differ between NAC and NACRT. In reassessment after NAT, the specific type of therapy administered, that is, NAC or NACRT, must be considered, especially in cases wherein radiographic alterations are minimal.