Table 2.
Pathologic characteristics and oncological outcomes
| Characteristic | Overall | After match (1:3) | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| With PAS (N = 35) | Without PAS (N = 168) | P value | With PAS (N = 32) | Without PAS (N = 96) | P value | |||||
| N | % | N | % | N | % | N | % | |||
| Preoperative clinical staging | ||||||||||
| Tumor depth | 0.9823 | 0.9270 | ||||||||
| T2 | 2 | 5.7% | 11 | 6.5% | 1 | 3.1% | 5 | 5.2% | ||
| T3 | 27 | 77.1% | 129 | 76.8% | 25 | 78.1% | 74 | 77.1% | ||
| T4 | 6 | 17.1% | 28 | 16.7% | 6 | 18.8% | 17 | 17.7% | ||
| Lymph node metastasis | 0.2970 | 0.9345 | ||||||||
| N0 | 11 | 31.4% | 33 | 19.6% | 8 | 25.0% | 26 | 27.1% | ||
| N1 | 15 | 42.9% | 88 | 52.4% | 15 | 46.9% | 46 | 47.9% | ||
| N2 | 9 | 25.7% | 47 | 28.0% | 9 | 28.1% | 24 | 25.0% | ||
| AJCC stage (clinical) | 0.3444 | 0.9846 | ||||||||
| I | 2 | 5.7% | 4 | 2.4% | 1 | 3.1% | 4 | 4.2% | ||
| II | 7 | 20.0% | 26 | 15.5% | 7 | 21.9% | 21 | 21.9% | ||
| III | 20 | 57.1% | 120 | 71.4% | 20 | 62.5% | 59 | 61.5% | ||
| IV | 6 | 17.1% | 18 | 10.7% | 4 | 12.5% | 12 | 12.5% | ||
| Postoperative pathological outcomes | ||||||||||
| Tumor size | 0.3634 | 0.2124 | ||||||||
| < 5 cm | 35 | 100.0% | 159 | 94.6% | 32 | 100.0% | 92 | 95.8% | ||
| ≥ 5 cm | 0 | 0.0% | 9 | 5.4% | 0 | 0.0% | 4 | 4.2% | ||
| Tumor size (cm) | ||||||||||
| Median (range) | 1.7 (0–4.5) | 1.7 (0–8.0) | 0.8658 | 1.8 (0–4.5) | 1.5 (0–8.0) | 0.4810 | ||||
| Mean ± SD | 1.8 ± 1.2 | 1.9 ± 1.7 | 0.6117 | 1.9 ± 1.2 | 1.7 ± 1.7 | 0.6547 | ||||
| Tumor depth | 0.6850 | 0.3077 | ||||||||
| T0 | 7 | 20.0% | 47 | 28.0% | 6 | 18.8% | 28 | 29.2% | ||
| Tis | 0 | 0.0% | 2 | 1.2% | 0 | 0.0% | 2 | 2.1% | ||
| T1 | 3 | 8.6% | 11 | 6.5% | 3 | 9.4% | 8 | 8.3% | ||
| T2 | 9 | 25.7% | 43 | 25.6% | 7 | 21.9% | 26 | 27.1% | ||
| T3 | 16 | 45.7% | 60 | 35.7% | 16 | 50.0% | 29 | 30.2% | ||
| T4 | 0 | 0.0% | 5 | 3.0% | 0 | 0.0% | 3 | 3.1% | ||
| Lymph node metastasis | 0.8948 | 0.8281 | ||||||||
| N0 | 27 | 77.1% | 126 | 75.0% | 24 | 75.0% | 72 | 75.0% | ||
| N1 | 7 | 20.0% | 32 | 19.0% | 7 | 21.9% | 18 | 18.8% | ||
| N2 | 1 | 2.9% | 9 | 5.4% | 1 | 3.1% | 5 | 5.2% | ||
| N3 | 0 | 0.0% | 1 | 0.6% | 0 | 0.0% | 1 | 1.0% | ||
| AJCC stage (pathologic) | 0.5986 | 0.7447 | ||||||||
| 0 | 6 | 17.1% | 45 | 26.8% | 6 | 18.8% | 27 | 28.1% | ||
| I | 10 | 28.6% | 36 | 21.4% | 9 | 28.1% | 23 | 24.0% | ||
| II | 8 | 22.9% | 35 | 20.8% | 8 | 25.0% | 16 | 16.7% | ||
| III | 5 | 14.3% | 32 | 19.0% | 5 | 15.6% | 17 | 17.7% | ||
| IV | 6 | 17.1% | 20 | 11.9% | 4 | 12.5% | 13 | 13.5% | ||
| Down stage of T stage | 0.4106 | 0.4188 | ||||||||
| Down stage | 23 | 65.7% | 116 | 69.0% | 21 | 65.6% | 72 | 75.0% | ||
| Unchanged | 12 | 34.3% | 46 | 27.4% | 11 | 34.4% | 23 | 24.0% | ||
| Up stage | 0 | 0.0% | 6 | 3.6% | 0 | 0.0% | 1 | 1.0% | ||
| Down stage of N stage | 0.6294 | 0.7574 | ||||||||
| Down stage | 21 | 60.0% | 112 | 66.7% | 21 | 65.6% | 57 | 59.4% | ||
| Unchanged | 13 | 37.1% | 49 | 29.2% | 10 | 31.3% | 34 | 35.4% | ||
| Up stage | 1 | 2.9% | 7 | 4.2% | 1 | 3.1% | 5 | 5.2% | ||
| Down stage of AJCCstage | 0.4548 | 0.8358 | ||||||||
| Down stage | 19 | 54.3% | 110 | 65.5% | 19 | 59.4% | 62 | 64.6% | ||
| Unchanged | 15 | 42.9% | 54 | 32.1% | 12 | 37.5% | 31 | 32.3% | ||
| Up stage | 1 | 2.9% | 4 | 2.4% | 1 | 3.1% | 3 | 3.1% | ||
| Tumor regression grade | 0.4980 | 0.3177 | ||||||||
| 0 | 7 | 20.6% | 46 | 28.6% | 6 | 19.4% | 27 | 30.3% | ||
| 1 | 14 | 41.2% | 68 | 42.2% | 13 | 41.9% | 39 | 43.8% | ||
| 2 | 11 | 32.4% | 34 | 21.1% | 10 | 32.3% | 16 | 17.4% | ||
| 3 | 2 | 5.9% | 13 | 8.1% | 2 | 6.5% | 8 | 8.4% | ||
| Tumor regression | 0.4992 | 0.1747 | ||||||||
| Good (0 + 1) | 21 | 61.8% | 114 | 70.8% | 19 | 61.3% | 66 | 74.2% | ||
| Poor (2 + 3) | 13 | 38.2% | 47 | 29.2% | 12 | 38.7% | 23 | 25.8% | ||
| Harvested lymph node | ||||||||||
| Median (range) | 10 (2–33) | 9 (0–36) | 0.7059 | 10 (2–23) | 9 (1–30) | 0.2360 | ||||
| Mean ± SD | 10.7 ± 5.8 | 10.3 ± 5.7 | 0.6939 | 11.2 ± 5.8 | 9.7 ± 5.5 | 0.2020 | ||||
| Positive lymph node | ||||||||||
| Median (range) | 0 (0–6) | 0 (0–24) | 0.6550 | 0 (0–6) | 0 (0–24) | 0.7394 | ||||
| Mean ± SD | 0.4 ± 1.1 | 0.6 ± 2.3 | 0.3068 | 0.4 ± 1.2 | 0.8 ± 3.0 | 0.3348 | ||||
| Harvested apical node | ||||||||||
| Median (range) | 2 (0–10) | 2 (0–10) | 0.6824 | 2 (0–10) | 2 (0–8) | 0.9269 | ||||
| Mean ± SD | 2.3 ± 2.1 | 2.4 ± 2.1 | 0.7417 | 2.3 ± 2.1 | 2.2 ± 1.8 | 0.7394 | ||||
| Positive apical node | ||||||||||
| Median (range) | 0 (0–3) | 0 (0–2) | 0.2219 | 0 (0–3) | 0 (0–2) | 0.3176 | ||||
| Mean ± SD | 0.2 ± 0.6 | 0.1 ± 0.3 | 0.2939 | 0.2 ± 0.6 | 0.1 ± 0.4 | 0.3540 | ||||
| Vascular invasion | 1.0000 | 0.9158 | ||||||||
| No | 31 | 91.2% | 143 | 91.7% | 28 | 90.3% | 81 | 91.0% | ||
| Yes | 3 | 8.8% | 13 | 8.3% | 3 | 9.7% | 8 | 8.99% | ||
| Perineural invasion | 0.6028 | 0.8250 | ||||||||
| No | 29 | 85.3% | 128 | 81.5% | 26 | 83.9% | 74 | 82.22% | ||
| Yes | 5 | 14.7% | 29 | 18.5% | 5 | 16.1% | 16 | 17.78% | ||
| Distance of PRM (cm) | ||||||||||
| Median (range) | 5.0 (1.0–10.0) | 5.5 (0.8–58.0) | 0.3476 | 5.0 (1.0–10.0) | 5.8 (0.8–58.0) | 0.0924 | ||||
| Mean ± SD | 5.2 ± 1.8 | 6.1 ± 4.9 | 0.0813 | 5.2 ± 1.8 | 7.0 ± 7.5 | 0.0412 | ||||
| Distance of DRM (cm) | ||||||||||
| Median (range) | 2.1 (0.1–8.1) | 2 (0.1–7.5) | 0.7923 | 2.4 (0.1–8.1) | 2.0 (0.1–7.0) | 0.5231 | ||||
| Mean ± SD | 2.4 ± 1.9 | 2.3 ± 0.5 | 0.6451 | 2.4 ± 1.9 | 2.2 ± 1.5 | 0.4101 | ||||
| Distance of CRM (mm) | ||||||||||
| Median (range) | 11.5 (2.0–120.0) | 12.0 (1.0–120.0) | 0.9867 | 10.0 (2.0–120.0) 22.9 | 15.0 (1.0–98.0) | 0.5309 | ||||
| Mean ± SD | 23.0 ± 29.5 | 18.9 ± 20.9 | 0.4994 | ± 30.7 | 20.2 ± 20.5 | 0.6971 | ||||
| DRM | 0.1383 | 0.3322 | ||||||||
| Free | 33 | 94.3% | 166 | 98.8% | 30 | 93.8% | 93 | 97.4% | ||
| Positive | 2 | 5.7% | 2 | 1.2% | 2 | 6.3% | 3 | 2.6% | ||
| CRM | 1.0000 | 0.8828 | ||||||||
| Free | 34 | 97.1% | 161 | 97.0% | 31 | 96.9% | 93 | 96.9% | ||
| Positive | 1 | 2.9% | 5 | 3.0% | 1 | 3.1% | 3 | 3.1% | ||
| Resection degree of primary tumor | 0.6549 | 0.8224 | ||||||||
| R0 | 33 | 94.3% | 161 | 95.8% | 30 | 93.8% | 91 | 94.8% | ||
| R1 | 2 | 5.7% | 7 | 4.2% | 2 | 6.3% | 5 | 5.2% | ||
| Oncological outcomes (clinical stages I–III) | ||||||||||
| Follow-up periods (months) | ||||||||||
| Median (range) | 23.1 (8.4–74.6) | 28.6 (6.2–87.1) | 0.3183 | 22.5 (8.4–74.6) | 30.5 (6.2–87.1) | 0.4770 | ||||
| Mean ± SD | 29.0 ± 16.5 | 32.9 ± 19.3 | 0.2579 | 29.4 ± 17.1 | 33.1 ± 19.7 | 0.3499 | ||||
| Post-op relapse | 0.9904 | 0.8943 | ||||||||
| No | 24 | 82.8% | 124 | 82.7% | 23 | 82.1% | 70 | 83.3% | ||
| Yes | 5 | 17.2% | 26 | 17.3% | 5 | 17.9% | 14 | 16.7% | ||
| Post-op locoregional recurrent | 0.5913 | 0.0828 | ||||||||
| No | 28 | 96.6% | 146 | 97.3% | 27 | 96.4% | 84 | 100.0% | ||
| Yes | 1 | 3.4% | 4 | 2.7% | 1 | 3.6% | 0 | 0.0% | ||
| Post-op distant metastasis | 1.0000 | 0.7575 | ||||||||
| No | 25 | 86.2% | 128 | 85.3% | 24 | 85.7% | 70 | 83.3% | ||
| Yes | 4 | 13.8% | 22 | 14.7% | 4 | 14.3% | 14 | 16.7% | ||
| Death | 1.0000 | 0.9377 | ||||||||
| No | 31 | 88.6% | 150 | 89.3% | 28 | 87.5% | 85 | 88.5% | ||
| Yes | 4 | 11.4% | 18 | 10.7% | 4 | 12.5% | 11 | 11.5% | ||
| DFS (months) | ||||||||||
| Median (range) | 21.3 (8.4–74.6) | 24.4 (2.5–87.1) | 0.7826 | 20.9 (8.4–74.6) | 26.7 (2.5–87.1) | 0.8103 | ||||
| Mean ± SD | 27.6 ± 16.6 | 30.1 ± 19.7 | 0.5297 | 27.5 ± 16.9 | 29.8 ± 19.7 | 0.5773 | ||||
| OS (months) | ||||||||||
| Median (range) | 23.1 (8.4–74.6) | 28.4 (6.4–87.1) | 0.4110 | 22.5 (8.4–74.6) | 30.7 (7.0–87.1) | 0.4692 | ||||
| Mean ± SD | 29.1 ± 16.8 | 32.8 ± 19.4 | 0.3292 | 29.4 ± 17.1 | 33.0 ± 19.6 | 0.3395 | ||||
PAS previous abdominal surgery, AJCC American Joint Commission on Cancer, SD standard deviation, PRM proximal resection margin, DRM distal resection margin, CRM circumferential resection margin, DFS disease-free survival, OS overall survival