Table 4. Histopathologic characteristics and criteria for unresectability of 50 re-explored PDAC patients, stratified by neoadjuvant treatment.
| Characteristics | Neoadjuvant therapy (n=37) | No-neoadjuvant therapy (n=13) | P value |
|---|---|---|---|
| Histopathologic characteristics | |||
| pT stage, n (%) | 0.039† | ||
| T0 | 0 (0) | 0 (0) | |
| T1 | 11 (29.7) | 0 (0) | |
| T2 | 4 (10.8) | 1 (7.7) | |
| T3 | 21 (56.8) | 11 (84.6) | |
| T4 | 1 (2.7) | 1 (7.7) | |
| pN stage, n (%) | 0.002 | ||
| N0 | 24 (64.9) | 2 (15.4) | |
| N1 | 13 (35.1) | 11 (84.6) | |
| Tumor size, median (IQR) cm | 2.5 (1.5–3.5) | 3 (2.5–5.5) | 0.012 |
| Microvascular invasion, n (%) | 13 (35.1) | 10 (76.9) | 0.009 |
| Perineural invasion, n (%) | 24 (64.9) | 8 (61.5) | 0.83 |
| Positive nodes (n), median (IQR) | 0 (0–1.5) | 2 (1.0–5.0) | 0.025 |
| Total nodes (n), median (IQR) | 15 (12.0–19.0) | 18 (14.0–23.5) | 0.332 |
| Lymph node ratio, n (%) | 0.002†† | ||
| 0 | 24 (64.9) | 2 (15.4) | |
| 0–0.2 | 8 (21.6) | 7 (53.9) | |
| 0.2–0.4 | 3 (8.1) | 3 (23.1) | |
| >0.4 | 2 (5.4) | 1 (7.7) | |
| Resection, n (%) | 0.016§ | ||
| R0 | 34 (91.9) | 8 (61.5) | |
| R1 | 3 (8.1) | 2 (15.4) | |
| R2 | 0 (0) | 3 (23.1) | |
| Criteria for unresectability, n (%) | 0.474 | ||
| Vascular involvement | |||
| SMA | 3 (8.1) | 2 (15.4) | |
| Celiac axis/hepatic artery | 4 (10.8) | 0 (0) | |
| SMV/PV | 23 (62.2) | 6 (46.2) | |
| SMA and SMV | 1 (2.7) | 1 (7.7) | |
| Celiac or portal lymphadenopathy | 3 (8.1) | 2 (15.4) | |
| Unknown | 3 (8.1) | 2 (15.4) | |
| Overall survival, median (months) | 24 | 13 | 0.044 |
†, statistical analysis performed on T0–T2 vs. T3–T4 tumors; ††, statistical analysis performed on lymph node ratio =0 versus >0; §, statistical analysis performed on R0 resection versus no R0 resection. PDAC, pancreatic ductal adenocarcinoma; SMA, superior mesenteric artery; SMV, superior mesenteric vein; PV, portal vein; IQR, interquartile range.