Prognostic impacts of biological and conditional factors in patients with anatomically resectable pancreatic adenocarcinoma treated with preoperative chemoradiotherapy.

The efficacy of preoperative chemoradiotherapy (CRT) for anatomically resectable pancreatic adenocarcinoma (R-PDAC) remains contentious. This study aims to elucidate the treatment outcomes of preoperative CRT for R-PDAC and to identify prognostic factors. This retrospective study included 109 R-PDAC patients treated with gemcitabine- or S-1 plus gemcitabine-based preoperative CRT from February 2005 to April 2023. Cox proportional hazards regression was employed to identify factors associated with worse overall survival (OS). Among the 109 cases, 90 patients (82.6%) underwent curative-intent resection following CRT. The median OS for the entire cohort was 36.5 months, significantly longer in resected cases than in unresected cases (40.6 vs 11.4 months). Multivariate analysis identified pretreatment serum levels of carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9) and the Eastern Cooperative Oncology Group performance status ≥1 as independent prognostic factors. When these factors were scored (risk score 0-3) using pre-CRT serum CA19-9 level (≥640 U/mL) and CEA (≥6.1 ng/mL), OS for risk scores 1 (n = 41), 2 (n = 20) or 3 (n = 6) was significantly shorter than for risk score 0 (n = 42) (score 0 vs 1 vs 2 vs 3: 49.1 vs 33.8 vs 16.1 vs 16.8 months). The presence of portal vein invasion on imaging and post-CRT serum CA 19-9 level (≥111 U/mL) were independent prognostic factors in resected cases. Biological factors, including serum levels of CA19-9 and CEA, along with conditional factor of Eastern Cooperative Oncology Group performance status ≥1, were identified as independent prognostic factors for R-PDAC patients treated with preoperative CRT. Preoperative CRT is considered effective for cases lacking these risk factors.