Table 2.
Pathological characteristics of patients who underwent resection for pancreatic head cancer, stratified by cohort
| Characteristic | All resections | PDAC only | ||||
|---|---|---|---|---|---|---|
| Cohort A [n = 159] | Cohort B [n = 134] | p value | Cohort A [n = 96] | Cohort B [n = 98] | p value | |
| Etiology [n (%)] | 0.009 | – | – | – | ||
| PDAC | 96 (60.4) | 98 (73.1) | ||||
| Distal cholangiocarcinoma | 22 (13.8) | 18 (13.4) | ||||
| Carcinoma of the papilla of Vater | 38 (23.9) | 13 (9.7) | ||||
| Other or not specified | 3 (1.9) | 5 (3.7) | ||||
| Tumor size [mean (SD)] | 3.0 (1.2) | 3.1 (1.2) | 0.639 | 3.3 (1.1) | 3.3 (1.1) | 0.740 |
| N + [n (%)] | 110 (69.2) | 102 (76.2) | 0.186 | 77 (80.2) | 80 (81.6) | 0.801 |
| Number of analyzed nodes [median (range)] | 13 (2–38) | 16 (3–52) | 0.004 | 13 (2–38) | 16 (3–52) | 0.027 |
| Lymph node ratio [median (IQR)] | 0.12 (0–0.25) | 0.18 (0.04–0.30) | 0.063 | 0.18 (0.06–0.30) | 0.18 (0.06–0.29) | 0.993 |
| Number of analyzed PALNs [median (IQR)] | 2 (1–14) | 2 (1–10) | 0.950 | 2 (2–4) | 2.5 (1–4) | 0.737 |
| Number of involved PALNs, median (range) | 0 (0–2) | 0 (0–4) | < 0.001 | 0 (0–2) | 0 (0–4) | 0.017 |
| Lymph node ratio, PALNs [median (IQR)] | 0 (0–0) | 0 (0–0) | < 0.001 | 0 (0.0–0.0) | 0 (0.0–0.0) | 0.715 |
| Perineural invasiona [n (%)] | 109 (68.6) | 107 (85.6) | 0.001 | 83 (86.5) | 84 (91.3) | 0.292 |
| Angioinvasionb | 86 (54.4) | 89 (71.8) | 0.003 | 58 (60.4) | 68 (74.7) | 0.037 |
| Positive resection margins [n (%)] | 44 (27.7) | 60 (44.8) | 0.002 | 41 (42.7) | 51 (52.0) | 0.139 |
| Adjuvant chemotherapy [n (%)] | 37 (23.3) | 67 (50.0) | < 0.001 | 33 (34.4) | 62 (63.3) | < 0.001 |
Bold values indicate statistical significance
For comparison between two groups, the Mann–Whitney U test was used for continuous variables, and the Chi square or Fisher’s exact tests were used for binary variables as appropriate
aNine missing, cohort B
bOne missing, cohort A; 10 missing, cohort B
PALN para-aortic lymph node, PDAC pancreatic ductal adenocarcinoma, N+ positive lymph node status, SD standard deviation, IQR interquartile range