Table 1.
Baseline characteristics
| Demographic variable | Before matching | After matching | ||||
|---|---|---|---|---|---|---|
| Non-DLI group (n = 165) n (%) | DLI group (n = 45) n (%) | P | Non-DLI group (n = 25) n (%) | DLI group (n = 25) n (%) | P | |
| Sex | 0.622 | 0.765 | ||||
| Male | 102(61.8) | 26(57.8) | 17(68.0) | 16(64.0) | ||
| Female | 63(38.2) | 19(42.2) | 8(32.0) | 9(36.0) | ||
| Age(y) | 0.078 | 0.777 | ||||
| ≤ 60 | 108(65.5) | 23(51.1) | 14(56.0) | 13(52.0) | ||
| > 60 | 57(34.5) | 22(48.9) | 11(44.0) | 12(48.0) | ||
| ECOG performance status | 0.288 | 0.733 | ||||
| 0 | 133(80.6) | 33(73.3) | 19(76.0) | 20(80.0) | ||
| 1 | 32(19.4) | 12(26.7) | 6(24.0) | 5(20.0) | ||
| Baseline serum CEA level (ng/mL) | 0.629 | 1.000 | ||||
| ≤ 5 | 91(55.1) | 25(55.6) | 16(64.0) | 16(64.0) | ||
| > 5 | 61(37.0) | 14(31.1) | 9(36.0) | 9(36.0) | ||
| NA | 13(7.9) | 6(13.3) | 0(0.0) | 0(0.0) | ||
| c T Stage | 0.044 | 0.271 | ||||
| 2 | 9(5.5) | 3(6.7) | 0(0.0) | 2(8.0) | ||
| 3 | 100(60.6) | 18(40.0) | 13(52.0) | 9(36.0) | ||
| 4 | 56(33.9) | 24(53.3) | 12(48.0) | 14(56.0) | ||
| c N Stage | 0.348 | 1.000 | ||||
| 0 | 6(3.6) | 4(8.9) | 0(0.0) | 1(4.0) | ||
| 1 | 15(9.1) | 3(6.7) | 2(8.0) | 2(8.0) | ||
| 2 | 144(87.3) | 38(84.4) | 23(92.0) | 22(88.0) | ||
| Tumor histologic grade | 0.316 | 0.725 | ||||
| Well/Moderate differentiated adenocarcinoma | 133(80.6) | 37(82.2) | 20(80.0) | 19(76.0) | ||
| Poorly differentiated / Signet ring cell cancer or mucinous /adenocarcinoma | 24(14.6) | 8(17.8) | 4(16.0) | 6(24.0) | ||
| Unknown differentiated adenocarcinoma | 8(4.8) | 0(0.0) | 1(4.0) | 0(0.0) | ||
| Induction chemotherapy | 0.403 | 0.602 | ||||
| No | 153(92.7) | 40(88.9) | 24(96.0) | 22(88.0) | ||
| Yes | 12(7.3) | 5(11.1) | 1(4.0) | 3(12.0) | ||
| Concurrent chemotherapy | 0.175 | 1.000 | ||||
| No | 1(0.6) | 1(2.2) | 0(0.0) | 0(0.0) | ||
| Capecitabine | 139(84.2) | 34(75.6) | 20(80.0) | 20(80.0) | ||
| CAPEOX | 25(15.2) | 10(22.2) | 5(20.0) | 5(20.0) | ||
| Anterior pelvic organ invasion | 0.086 | 1.000 | ||||
| No | 153(92.7) | 38(84.4) | 21(84.0) | 21(84.0) | ||
| Yes | 12(7.3) | 7(15.6) | 4(16.0) | 4(16.0) | ||
| Consolidation chemotherapy | 0.526 | 0.382 | ||||
| No | 113(68.5) | 28(62.2) | 19(76.0) | 15(60.0) | ||
| Capecitabine | 38(23.0) | 14(31.1) | 4(16.0) | 9(36.0) | ||
| CAPEOX | 14(8.5) | 3(6.7) | 2(8.0) | 1(4.0) | ||
| Time interval between neoadjuvant chemoradiotherapy and surgery, median (IQR) (weeks) | 9.7(8.1–12.0) | 10.6(8.8–14.6) | 0.072 | 8.6(7.0–11.6) | 10.6(8.9–12.7) | 0.062 |
| Preoperative serum CEA level (ng/mL) | 0.027 | 0.700 | ||||
| ≤ 5 | 148(89.7) | 37(82.2) | 20(80.0) | 22(88.0) | ||
| > 5 | 11(6.7) | 8(17.8) | 5(20.0) | 3(12.0) | ||
| NA | 6(3.6) | 0(0) | 0(0.0) | 0(0.0) | ||
| Type of surgery | 0.016 | - | ||||
| Abdominoperineal resection | 137(83.0) | 45(100.0) | 25(100.0) | 25(100.0) | ||
| Low/ultralow anterior resection | 22(13.4) | 0(0.0) | 0(0.0) | 0(0.0) | ||
| Hartmann procedure | 1(0.6) | 0(0.0) | 0(0.0) | 0(0.0) | ||
| Transanal total mesorectal excision | 4(2.4) | 0(0.0) | 0(0.0) | 0(0.0) | ||
| Intersphincteric resection | 1(0.6) | 0(0) | 0(0.0) | 0(0.0) | ||
| Surgical technique | 0.278 | 0.777 | ||||
| Open surgery | 92(55.8) | 21(46.7) | 13(52.0) | 14(56.0) | ||
| Laparoscopic surgery | 73(44.2) | 24(53.3) | 12(48.0) | 11(44.0) | ||
| Operation duration, median (IQR) (min) | 185(124–236) | 208(163–273) | 0.118 | 180(126.5–222.5) | 194(105–250) | 0.839 |
| Intraoperative blood loss, median (IQR) (ml) | 100(50–200) | 100(50–100) | 0.257 | 100(100–150) | 100(50–100) | 0.403 |
| Number of lymph nodes examined in the surgery, median (IQR) | 9(5–12) | 9(4–12) | 0.655 | 9(6.5–11) | 7(4–11.5) | 0.307 |
| Lymphovascular invasiona | 1.000 | - | ||||
| Negative | 161(97.6) | 43(95.6) | 25(100.0) | 25(100.0) | ||
| Positive | 3(1.8) | 1(2.2) | 0(0.0) | 0(0.0) | ||
| NA | 1(0.6) | 1(2.2) | 0(0.0) | 0(0.0) | ||
| Perineural invasiona | 0.136 | 1.000 | ||||
| Negative | 153(92.7) | 38(84.5) | 24(96.0) | 23(92.0) | ||
| Positive | 11(6.7) | 6(13.3) | 1(4.0) | 2(8.0) | ||
| NA | 1(0.6) | 1(2.2) | 0(0.0) | 0(0.0) | ||
| Resection margin | 0.220 | 1.000 | ||||
| R0 | 162(98.2) | 42(93.3) | 24(96.0) | 25(100.0) | ||
| R1 | 3(1.8) | 3(6.7) | 1(4.0) | 0(0.0) | ||
| ypT stage | 0.807 | 0.229 | ||||
| 0 | 40(24.2) | 9(20.0) | 4(16.0) | 9(36.0) | ||
| 1–2 | 76(46.1) | 21(46.7) | 16(64.0) | 11(44.0) | ||
| 3–4 | 49(29.7) | 15(33.3) | 5(20.0) | 5(20.0) | ||
| ypN stage | 0.928 | 1.000 | ||||
| 0 | 133(80.6) | 36(80.0) | 22(88.0) | 21(84.0) | ||
| 1–2 | 32(19.4) | 9(20.0) | 3(12.0) | 4(16.0) | ||
| Postoperative complications | 0.008 | 1.000 | ||||
| No | 125(75.8) | 25(55.6) | 15(60.0) | 16(64.0) | ||
| Clavien- Dindo Grade I-II | 32(19.4) | 19(42.2) | 8(32.0) | 8(32.0) | ||
| Clavien- Dindo Grade III-V | 8(4.8) | 1(2.2) | 2(8.0) | 1(4.0) | ||
| Adjuvant chemotherapy | 0.828 | 0.057 | ||||
| No | 57(34.5) | 16(35.5) | 12(48.0) | 11(44.0) | ||
| Capecitabine | 27(16.4) | 9(20.0) | 1(4.0) | 7(28.0) | ||
| CAPEOX or mFOLFOX6 | 68(41.2) | 17(37.8) | 12(48.0) | 7(28.0) | ||
| NA | 13(7.9) | 3(6.7) | 0(0.0) | 0(0.0) | ||
Abbreviations: c clinical, CEA carcinoembryonic antigen, CRM circumferential resection margin, DLI dentate line invasion, ECOG Eastern Cooperative Oncology Group, IQR interquartile range, NA not available, p pathological, RT radiotherapy, SD standardized difference, yp yield pathological
aEvaluated by postoperative pathology examination