Table 1.
Patient demographics and treatment variables.
| Variables | Crude analysis: neoadjuvant n = 1613 | PSM: no neoadjuvant n = 354 | PSM: neoadjuvant n = 354 | SMD | Crude analysis: adjuvant n = 1176 | PSM: no adjuvant n = 389 | PSM: adjuvant n = 389 | SMD |
|---|---|---|---|---|---|---|---|---|
| Male sex n (%) | 723 (45) | 153 (43) | 165 (47) | 0.068 | 532 (45) | 166 (43) | 163 (42) | 0.016 |
| Age mean (SD) | 56 (12) | 56 (13) | 55 (12) | 0.049 | 57 (12) | 57 (12) | 57 (12) | 0.010 |
| Liver metastases n (%) | 208 (13) | 39 (11) | 52 (15) | 0.110 | 178 (15) | 48 (12) | 55 (14) | 0.053 |
| Node positive n (%) | 1185 (73) | 266 (75) | 253 (72) | 0.083 | 856 (73) | 283 (73) | 282 (72) | 0.006 |
| Timing of PM n (%) | 0.091 | 0.075 | ||||||
| Metachronous | 797 (50) | 183 (52) | 167 (47) | 594 (51) | 212 (55) | 209 (54) | ||
| Synchronous | 746 (46) | 154 (43) | 168 (48) | 577 (49) | 174 (45) | 179 (46) | ||
| Missing data | 70 (4) | 17 (5) | 19 (5) | 5 (<1) | 3 (<1) | 1 (<1) | ||
| Neoadj chemo n (%) | 1162 (72) | 0 (0) | 354 (100) | N/A | 891 (76) | 285 (73) | 285 (73) | 0.012 |
| Adjuvant chemo n (%) | 739 (46) | 66 (19) | 74 (21) | 0.081 | 720 (61) | 0 (0) | 389 (100) | N/A |
| Missing adjuvant data n (%) | 409 (25) | 188 (53) | 174 (49) | 0 (0) | 0 (0) | 0 (0) | N/A | |
| No periop chemo n (%) | 122 (8) | 100 (28) | 0 (0) | N/A | 120 (10) | 104 (27) | 0 (0) | N/A |
| PCI mean (SD) | 10.1 (7.1) | 10.9 (7.3) | 11.8 (7.6) | 0.114 | 9.6 (6.9) | 9.8 (7.6) | 9.5 (6.7) | 0.038 |
| CC score 0 n (%) | 1498 (93) | 330 (93) | 316 (89) | 0.172 | 1110 (94) | 369 (95) | 370 (95) | 0.010 |
| CC score 1 | 85 (5) | 20 (6) | 26 (7.3) | 59 (5) | 18 (5) | 17 (4) | ||
| CC score 2 | 21 (1) | 3 (<1) | 10 (2.8) | 5 (<1) | 2 (<1) | 2 (<1) | ||
| CC score 3 | 9 (<1) | 1 (<1) | 2 (0.6) | 2 (<1) | 0 (0) | 0 (0) | ||
| HIPEC n (%) | 0.023 | 0.043 | ||||||
| Cisplatin | 3 (<1) | 1 (<1) | 1 (<1) | 3 (<1) | 1 (<1) | 1 (<1) | ||
| Irinotecan | 4 (<1) | 2 (<1) | 2 (<1) | 4 (<1) | 2 (<1) | 1 (<1) | ||
| Mitomycin | 659 (41) | 155 (44) | 151 (43) | 400 (34) | 146 (38) | 144 (37) | ||
| Oxaliplatin ± irinotecan | 947 (59) | 196 (55) | 200 (56) | 769 (65) | 240 (62) | 243 (63) | ||
| Primary tumour n (%) | 0.141 | 0.049 | ||||||
| Colon | 1322 (82) | 285 (80) | 293 (83) | 1075 (91) | 361 (93) | 356 (92) | ||
| Rectum | 124 (8) | 34 (10) | 21 (6) | 93 (8) | 26 (7) | 31 (8) | ||
| Missing data | 167 (10) | 35 (10) | 40 (11) | 8 (1) | 2 (<1) | 2 (<1) | ||
| Clavien-Dindo 3+ | 0.099 | 0.096 | ||||||
| No | 897 (56) | 207 (59) | 216 (61) | 714 (61) | 221 (57) | 239 (61) | ||
| Yes | 527 (33) | 107 (30) | 92 (26) | 433 (37) | 159 (41) | 143 (37) | ||
| Missing data | 189 (12) | 40 (11) | 46 (13) | 29 (2) | 9 (2) | 7 (2) | ||
| Postop mortality n (%) | 28 (1.7) | 2 (0.6) | 6 (1.7) | 0.116 | N/A | N/A | N/A | 0 |
| Return to OR n (%) | 0.085 | 0.039 | ||||||
| No | 1153 (72) | 250 (71) | 261 (74) | 943 (80) | 309 (79) | 315 (81) | ||
| Yes | 226 (14) | 51 (14) | 50 (14) | 164 (14) | 61 (16) | 56 (14) | ||
| Missing data | 234 (14) | 53 (15) | 43 (12) | 69 (6) | 19 (5) | 18 (5) | ||
| Median surgery date | 18-07-2012 | 12-12-2011 | 06-09-2011 | 0.032 | 15-06-2013 | 21-02-2013 | 08-08-2013 | 0.161 |
CC – completeness of cytoreduction, HIPEC – hyperthermnic intraperitoneal chemotherapy, OR – operating room, N/A – not applicable, PCI – peritoneal cancer index, PSM – propensity score matched, SD – standard deviation, SMD – standardized mean differences.