Table 1.
Association between baseline characteristics before and after propensity score-matching
| Variables | Overall cohort | Matched cohort | ||||
|---|---|---|---|---|---|---|
| MIS | Open | MIS | Open | |||
| (n = 33) | (n = 36) | p value | (n = 23) | (n = 23) | p value | |
| Patient factors | ||||||
| Age (years)* | 67 (57–74) | 63 (53–75) | 0.4598 | 67 (51–76) | 63 (52–76) | 0.7751 |
| Gender | ||||||
| Male | 19 (57.6) | 17 (47.2) | 0.3893 | 13 (56.5) | 9 (39.1) | 0.2365 |
| Female | 14 (42.4) | 19 (51.8) | 10 (43.5) | 14 (60.9) | ||
| BMI (kg/m2)* | 21.0 (19.0–23.7) | 20.6 (19.3–22.2) | 0.7548 | 21.3 (19.3–23.5) | 20.3 (19.0–21.5) | 0.3545 |
| ASA-PS score | ||||||
| I | 12 (36.4) | 11 (30.6) | 0.7936 | 7 (30.4) | 8 (34.8) | 0.9507 |
| II | 20 (60.6) | 23 (63.9) | 15 (65.2) | 14 (60.8) | ||
| III | 1 (3.0) | 2 (5.5) | 1 (4.4) | 1 (4.4) | ||
| Charlson comorbidity index | ||||||
| 0 | 25 (75.8) | 32 (88.8) | 0.3516 | 17 (73.9) | 21 (91.2) | 0.2607 |
| 1 | 4 (12.1) | 2 (10.6) | 4 (17.4) | 1 (4.4) | ||
| 2 | 4 (12.1) | 2 (10.6) | 2 (8.7) | 1 (4.4) | ||
| Perioperative therapy factors | ||||||
| Preoperative therapy | ||||||
| Chemoradiotherapy | 11 (33.3) | 15 (41.7) | 0.5150 | 7 (30.4) | 8 (34.8) | 0.9054 |
| Radiotherapy | 1 (3.0) | 1 (2.8) | 1 (4.4) | 1 (4.4) | ||
| Chemotherapy | 2 (6.1) | 5 (13.9) | 1 (4.4) | 2 (8.7) | ||
| None | 19 (57.6%) | 15 (41.7) | 14 (60.8) | 12 (52.1) | ||
| Preoperative decompression | ||||||
| Stent | 1 (3.0) | 1 (2.8) | 0.0787 | 1 (4.4) | 0 | 0.0558 |
| Colostomy | 1 (3.0) | 7 (19.4) | 1 (4.4) | 6 (26.1) | ||
| None | 31 (94.0) | 28 (77.8) | 21 (91.2) | 17 (73.9) | ||
| Adjuvant chemotherapy | 15 (45.5) | 12 (33.3) | 0.3024 | 10 (43.5) | 6 (26.1) | 0.2138 |
| Tumor factors | ||||||
| Distance from AV (cm)* | 6.0 (2.3–10) | 7.5 (3.9–12) | 0.2839 | 9.0 (3.0–11) | 8.0 (6.0–12) | 0.7327 |
| Residual tumor size (cm)* | 6.0 (3.9–7.1) | 5.0 (3.0–6.9) | 0.3934 | 6.0 (4.0–7.7) | 5.2 (3.4–7.5) | 0.3791 |
| (y)p T-stage | ||||||
| T2 | 2 (6.0) | 0 | 0.3610 | 0 | 0 | 1.0000 |
| T3 | 9 (27.3) | 11 (30.6) | 7 (30.4) | 7 (30.4) | ||
| T4a | 5 (15.2) | 7 (19.4) | 4 (17.4) | 4 (17.4) | ||
| T4b | 17 (51.5) | 18 (50.0) | 12 (52.2) | 12 (52.2) | ||
| (y)pN metastasis | ||||||
| 0 | 14 (42.4) | 21 (58.3) | 0.3120 | 11 (47.8) | 13 (56.5) | 0.5134 |
| 1 | 10 (30.3) | 9 (25.0) | 6 (26.1) | 6 (26.1) | ||
| 2 | 6 (18.2) | 2 (5.6) | 4 (17.4) | 1 (4.4) | ||
| 3 | 3 (9.1) | 4 (11.1) | 2 (8.7) | 3 (13.0) | ||
| (y)pM metastasis | 7 (21.2) | 8 (22.2) | 0.9190 | 5 (21.7) | 4 (17.4) | 0.7099 |
| Histopathological type | ||||||
| Differentiated (Well/Moderate) | 28 (84.9) | 32 (88.9) | 0.6187 | 20 (87.0) | 21 (91.3) | 0.6347 |
| Others | 5 (15.1) | 4 (11.1) | 3 (13.0) | 2 (8.7) | ||
| Resection margin status | ||||||
| R0 | 29 (87.9) | 34 (94.4) | 0.3306 | 20 (87.0) | 21 (91.3) | 0.6347 |
| R1 | 4 (12.1) | 2 (5.6) | 3 (13.0) | 2 (8.7) | ||
| R2 | 0 | 0 | 0 | 0 | ||
| Surgical factors | ||||||
| Surgical procedure | ||||||
| Low anterior resection | 19 (57.6) | 19 (52.7) | 0.0008 | 15 (65.2) | 17 (73.9) | 0.7945 |
| Abdominal perineal resection | 10 (30.3) | 5 (13.9) | 7 (30.4) | 5 (21.7) | ||
| Intersphincteric resection | 3 (9.1) | 0 | 0 | 0 | ||
| Total pelvic exenteration | 0 | 6 (16.7) | 0 | 0 | ||
| Hartmann’s procedure | 0 | 5 (13.9) | 0 | 0 | ||
| High anterior resection | 1 (3.0) | 1 (2.8) | 1 (4.4) | 1 (4.4) | ||
| LPN dissection | 7 (21.2) | 6 (16.7) | 0.6297 | 5 (21.7) | 4 (17.4) | 0.7099 |
| Harvested lymph nodes* | 22 (13–30) | 23 (12–38) | 0.6522 | 22 (10–30) | 24 (13–35) | 0.7835 |
Values in parentheses are percentages, unless indicated otherwise
MIS Minimally invasive surgery, BMI Body mass index, ASA-PS score American Society of Anesthesiologists-Physical Status score, AV Anal verge, LPN Lateral pelvic node
*Values are median (interquartile range)