Table 2. Pathologic characteristics and oncological outcomes of 116 patients who underwent preoperative concurrent chemoradiotherapy followed by robotic rectal surgery.
| Characteristic | All patients (N = 116) | Time interval between radiotherapy completion and robotic surgery | |||
|---|---|---|---|---|---|
| Group A (10–12 weeks) (N = 57) | Group B (≥ 12 weeks) (N = 59) |
P value | |||
| Preoperative clinical staging | |||||
| Tumor depth | 0.092 | ||||
| T2 | 6 (5.2%) | 3 (5.3%) | 3 (5.1%) | ||
| T3 | 91 (76.5%) | 49 (86.0%) | 42 (71.2%) | ||
| T4 | 19 (15.2%) | 5 (8.7%) | 14 (23.7%) | ||
| Lymph Node metastasis | 0.540 | ||||
| N0 | 26 (22.4%) | 14 (24.6%) | 12 (20.3%) | ||
| N1 | 63 (54.3%) | 28 (49.1%) | 35 (59.4%) | ||
| N2 | 27 (23.3%) | 15 (26.3%) | 12 (20.3%) | ||
| AJCCa Stage (Clinical) | 0.771 | ||||
| I | 3 (2.6%) | 2 (3.5%) | 1 (1.7%) | ||
| II | 23 (19.8%) | 12 (21.1%) | 11 (18.6%) | ||
| III | 90 (77.6%) | 43 (75.4%) | 47 (79.7%) | ||
| Postoperative pathological outcomes | |||||
| Tumor size | 1.000# | ||||
| < 5 cm | 111 (95.7%) | 55 (96.5%) | 56 (94.9%) | ||
| ≥ 5 cm | 5 (4.3%) | 2 (3.5%) | 3 (5.1%) | ||
| Tumor size (cm) | |||||
| Mean ± SDc (range) | 1.8 ± 1.8 (0.0–8.0) | 2.3 ± 1.8 (0.0–5.8) | 1.8 ± 1.7 (0.0–8.0) | 0.273 | |
| Median | 1.5 | 1.5 | 1.5 | ||
| Tumor depth | 0.655 | ||||
| T0 | 37 (31.9%) | 17 (29.8%) | 20 (33.9%) | ||
| Tis | 1 (0.9%) | 1 (1.8%) | 0 (0.0%) | ||
| T1 | 10 (8.6%) | 5 (8.8%) | 5 (8.5%) | ||
| T2 | 29 (25.0%) | 14 (24.6%) | 15 (25.4%) | ||
| T3 | 37 (31.9%) | 20 (35.0%) | 17 (28.8%) | ||
| T4 | 2 (1.7%) | 0 (0.0%) | 2 (3.4%) | ||
| Lymph Node metastasis | 0.193 | ||||
| N0 | 95 (81.9%) | 43 (75.4%) | 52 (88.1%) | ||
| N1 | 17 (14.7%) | 11 (19.3%) | 6 (10.2%) | ||
| N2 | 4 (3.4%) | 3 (5.3%) | 1 (1.7%) | ||
| AJCCa Stage (Pathologic) | 0.307 | ||||
| 0 | 31 (1.7%) | 18 (31.6%) | 19 (32.2%) | ||
| I | 32 (27.6%) | 13 (22.7%) | 19 (32.2%) | ||
| II | 26 (22.5%) | 12 (21.1%) | 14 (23.7%) | ||
| III | 21 (18.0%) | 14 (24.6%) | 7 (11.9%) | ||
| Down Stage of T Stage | 0.485 | ||||
| Down Stage | 84 (72.4%) | 40 (70.2%) | 44 (74.6%) | ||
| Unchanged | 31 (26.7%) | 17 (57.8%) | 14 (23.7%) | ||
| Up Stage | 1 (0.9%) | 0 (0.0%) | 1 (1.7%) | ||
| Down Stage of N Stage | 0.476 | ||||
| Down Stage | 82 (71.3%) | 38 (67.9%) | 44 (74.6%) | ||
| Unchanged | 32 (27.8%) | 17 (30.4%) | 15 (25.4%) | ||
| Up Stage | 1 (0.9%) | 1 (1.7%) | 0 (0.0%) | ||
| Down Stage of AJCCa Stage | 0.073 | ||||
| Down Stage | 100 (86.2%) | 45 (78.9%) | 55 (93.2%) | ||
| Unchanged | 15 (12.9%) | 11 (19.3%) | 4 (6.8%) | ||
| Up Stage | 1 (0.9%) | 1 (1.8%) | 0 (0.0%) | ||
| Tumor Regression Grade | 0.713 | ||||
| 0 | 37 (32.8%) | 18 (31.6%) | 20 (33.9%) | ||
| 1 | 55 (46.6%) | 29 (50.9%) | 25 (42.4%) | ||
| 2 | 16 (13.8%) | 6 (10.5%) | 10 (16.9%)v | ||
| 3 | 8 (6.9%) | 4 (7.0%) | 4 (6.8%) | ||
| Tumor Regression | 0.411 | ||||
| Good (0+1) | 92 (79.3%) | 47 (82.5%) | 45 (76.3%) | ||
| Poor (2+3) | 24 (20.7%) | 10 (17.5%) | 14 (2.7%) | ||
| Harvested Lymph Node | |||||
| Mean ± SDc (range) | 9.8 ± 5.21 (0–30) | 9.3 ± 5.1 (2–23) | 9.9 ± 5.2 (0–30) | 0.682 | |
| Median | 9.0 | 10.0 | |||
| Positive Lymph Node | |||||
| Mean ± SDc (range) | 0.5 ± 2.3 (0–24) | 0.3 ± 0.6 (0.0–2.0) | 0.5 ± 2.4 (0.0–24.0) | 0.725 | |
| Median | 0.0 | 0.0 | 0.0 | ||
| Harvested Apical Node | |||||
| Mean ± SDc (range) | 2.2 ± 1.9 (0–10) | 1.4 ± 1.4 (0.0–3.0) | 2.4 ± 2.0 (0.0–10.0) | 0.051 | |
| Median | 2.0 | 2.0 | 2.0 | ||
| Positive Apical Node | |||||
| Mean ± SDc (range) | 0.02 ± 0.12 (0–1) |
|
0.02 ± 0.13 (0.0–1.0) | 0.600 | |
| Median | 0.0 | 0.0 | 0.0 | ||
| Vascular invasion | 0.198# | ||||
| No | 104 (95.4%) | 49 (92.5%) | 55 (98.2%) | ||
| Yes | 5 (4.6%) | 4 (7.5%) | 1 (1.8%) | ||
| Perineural invasion | 0.728 | ||||
| No | 91 (84.3%) | 44 (83.0%) | 47 (85.5%) | ||
| Yes | 17 (15.7%) | 9 (17.0%) | 8 (14.5%) | ||
| Distance of proximal resection margin (cm) |
0.817 |
||||
| Mean ± SDc (range) | 6.0 ± 2.6 (1.0–19.0) | 6.1 ± 2.4 (2.0–11.0) | 6.4 ± 5.6 (2.5–12.5) | ||
| Median | 6.0 | 5.0 | 6.0 | ||
| Distance of distal resection margin (cm) | |||||
| Mean ± SDc (range) | 2.4 ± 1.6 (0.1–8.1) | 2.2 ± 1.2 (0.1–5.0) | 2.4 ± 1.7 (1.0–8.0) | 0.653 | |
| Median | 2.2 | 2.5 | 2.0 | ||
| Circumferential resection margin | |||||
| Free | 114 (98.3%) | 57 (100.0%) | 57 (96.6%) | 0.496# | |
| Positive | 2 (1.7%) | 0 (0.0%) | 2 (3.4%) | ||
| Distal resection margin | |||||
| Free | 115 (99.1%) | 57 (100.0%) | 58 (98.3%) | 1.000# | |
| Positive | 1 (0.9%) | 0 (0.0%) | 1 (1.7%) | ||
| Resection Degree of Primary tumor | |||||
| R0 | 113 (97.4%) | 57 (100.0%) | 56 (94.9%) | 0.244# | |
| R1 | 3 (2.6%) | 0 (0.0%) | 3 (5.1%) | ||
| Oncological outcomes | |||||
| Follow-up periods (months, median) (range) | 30.0 (11.4–83.4) | 28.3 (11.4–67.5) | 30.4 (12.7–83.4) | ||
| Post-op relapse | 0.093 | ||||
| No | 90 (77.6%) | 48 (84.2%) | 42 (71.2%) | ||
| Yes | 26 (22.4%) | 9 (15.8%) | 17 (28.8%) | ||
| Post-op locoregional Relapse | 0.119# | ||||
| No | 112 (96.6%) | 57 (100.0%) | 55 (93.2%) | ||
| Yes | 4 (3.4%) | 0 (0.0%) | 4 (6.8%) | ||
| Post-op distant Relapse | 0.391 | ||||
| No | 94 (81.0%) | 48 (84.2%) | 46 (78.0%) | ||
| Yes | 22 (19.0%) | 9 (15.8%) | 13 (22.0%) | ||
| Post-op mortality | 0.125# | ||||
| No | 104 (89.7%) | 54 (94.7%) | 50 (84.7%) | ||
| Yes | 12 (10.3%) | 3 (5.3%) | 9 (15.3%) | ||
| DFSd (Median, Range) (Months) | 27.6 (8.1–83.4) | 27.6 (11.4–67.5) | 27.6 (8.1–83.4) | ||
| OSe (Median, Range) (Months) | 30.0 (11.4–83.4) | 28.3 (11.4–67.5) | 30.4 (12.7–83.4) | ||
aAJCC American Joint Commission on Cancer
b NA not available
c SD standard deviation
d DFS disease-free survival
e OS overall survival
# Fisher exact test.