Table 1. Baseline Characteristics of Unmatched Populations of Patients With Enteropancreatic Neuroendocrine Tumors Who Received Upfront PRRT or Upfront Chemotherapy or Targeted Therapy.
| Variable | Patientsa | P valueb | SMDc | Standardized bias, %d | ||
|---|---|---|---|---|---|---|
| Total (N = 508) | Chemotherapy or targeted therapy (n = 179) | PRRT (n = 329) | ||||
| Time to progression during first-line SSA therapy, mean (SD), mo | 26.9 (3.1) | 32.7 (8.1) | 23.8 (1.7) | .16 | 0.12 | 64.1 |
| Sex | ||||||
| Female | 230 (45.3) | 79 (44.1) | 151 (45.9) | .38 | 0.03 | 3.4 |
| Male | 278 (54.7) | 100 (55.9) | 178 (54.1) | |||
| Age, mean (SD), y | 55.7 (0.5) | 55.3 (0.9) | 55.9 (0.6) | .51 | 0.06 | 6.3 |
| ECOG performance status | ||||||
| ≤1 | 478 (94.1) | 167 (93.3) | 311 (94.5) | .50 | 0.10 | 5.1 |
| >2 | 25 (4.9) | 11 (6.1) | 14 (4.3) | |||
| Data missing | 5 (1.0) | 1 (0.6) | 4 (1.2) | |||
| Site of tumor origin | ||||||
| Pancreas | 260 (51.2) | 137 (76.5) | 123 (37.4) | <.001 | 0.84 | 86.4 |
| Intestine | 248 (48.8) | 42 (23.5) | 206 (62.6) | |||
| Functioning | ||||||
| No | 162 (31.8) | 42 (23.5) | 120 (36.5) | .008 | 0.29 | 30.4 |
| Yes | 345 (67.9) | 137 (76.5) | 208 (63.2) | |||
| Data missing | 1 (0.2) | 0 | 1 (0.3) | |||
| MEN1 syndrome | ||||||
| No | 502 (98.8) | 178 (99.4) | 324 (98.5) | .67 | 0.08 | 10.3 |
| Yes | 6 (1.2) | 1 (0.6) | 5 (1.5) | |||
| Grade according to 2019 WHO classificiation20 | ||||||
| 1 | 203 (40.0) | 49 (27.4) | 154 (46.8) | <.001 | 0.38 | 85.3 |
| 2 | 272 (53.5) | 112 (62.6) | 160 (48.6) | |||
| 3 | 15 (2.9) | 11 (6.1) | 4 (1.2) | |||
| Data missing | 18 (3.5) | 7 (3.9) | 11 (3.3) | |||
| Ki-67 proliferation index >10% | ||||||
| No | 408 (80.3) | 125 (69.8) | 283 (86.0) | <.001 | 0.33 | 40.3 |
| Yes | 78 (15.4) | 45 (25.2) | 33 (10.0) | |||
| Data missing | 22 (4.3) | 9 (5.0) | 13 (4.0) | |||
| Surgery for primary tumor | ||||||
| No | 171 (33.7) | 83 (46.4) | 88 (26.8) | <.001 | 0.47 | 45.4 |
| Yes | 337 (66.3) | 96 (53.6) | 241 (73.3) | |||
| Metastases | ||||||
| Synchronous | 432 (85.0) | 152 (84.9) | 280 (85.1) | >.99 | 0.01 | 3.9 |
| Metachronous | 76 (15.0) | 27 (15.1) | 49 (14.9) | |||
| Surgery for metastases | ||||||
| No | 360 (70.9) | 128 (71.5) | 232 (70.5) | .82 | 0.13 | 4.1 |
| Yes | 146 (28.7) | 51 (28.5) | 95 (28.8) | |||
| Data missing | 2 (0.4) | 0 | 2 (0.6) | |||
| Metastatic sites, No. | ||||||
| 1 | 186 (36.6) | 67 (37.4) | 119 (36.2) | .22 | 0.04 | 14.8 |
| 2 | 179 (35.2) | 67 (37.4) | 112 (34) | |||
| ≥3 | 117 (23.1) | 33 (18.4) | 84 (25.5) | |||
| Data missing | 26 (5.1) | 12 (6.7) | 14 (4.3) | |||
| Metastatic sites | ||||||
| Not reported | 26 (5.1) | 12 (6.7) | 14 (4.3) | .58 | 0.11 | 9.8 |
| Liver | 166 (32.7) | 61 (34.1) | 105 (31.9) | |||
| Liver and extrahepatic | 288 (56.7) | 97 (54.2) | 191 (58.1) | |||
| Extrahepatic | 28 (5.5) | 9 (5.0) | 19 (5.8) | |||
| Hepatic locoregional treatment | ||||||
| No | 375 (73.8) | 128 (71.5) | 247 (75.1) | .39 | 0.08 | 6.6 |
| Yes | 133 (26.2) | 51 (28.5) | 82 (24.9) | |||
| Sequence completede | ||||||
| No | 12 (2.4) | 0 | 12 (3.7) | .01 | 0 | 0 |
| Yes | 496 (97.6) | 179 (100) | 317 (96.3) | |||
| SSA during PRRT | ||||||
| No | 62 (12.2) | 24 (13.4) | 38 (11.6) | .50 | 0.08 | 6.3 |
| Standard | 443 (87.2) | 155 (86.6) | 288 (87.5) | |||
| High dose | 3 (0.6) | 0 | 3 (0.9) | |||
| Cycles of PRRT, mean (SD), No. | 4.7 (0.1) | 4.2 (0.1) | 5.0 (0.1) | <.001 | 0.49 | 50.8 |
| Radionuclide | ||||||
| Not reported | 12 (2.4) | 1 (0.6) | 11 (3.3) | .007 | 0.40 | 16.3 |
| Yttrium-90 | 115 (22.6) | 54 (30.2) | 61 (18.5) | |||
| Lutetium-177 | 224 (44.1) | 75 (41.9) | 149 (45.3) | |||
| Both | 157 (30.9) | 49 (27.4) | 108 (2.8) | |||
Abbreviations: ECOG, Eastern Cooperative Oncology Group; MEN1, multiple endocrine neoplasm type 1; PRRT, peptide receptor radionuclide therapy; SMD, standardized mean difference; SSA, somatostatin analogue; WHO, World Health Organization.
Data are reported as the number (percentage) of patients unless otherwise indicated.
The Fisher exact test was used for binary variables, the Pearson χ2 test for ordinal variables, and the Student t test for continuous variables.
Effect size categories: small, 0 to 0.2 (nonoverlap population <15%); medium, greater than 0.2 to 0.5 (nonoverlap population <33%); large, greater than 0.5 to 0.8 (nonoverlap population <50%); and very large, greater than 0.8 (nonoverlap population >50%).
Standardized bias reflects the selection bias as a percentage; a value less than 15% indicated an optimal balance.
In the upfront chemotherapy or targeted therapy group, the sequence was considered completed when PRRT was used after chemotherapy or targeted therapy failure; in the upfront PRRT group, the sequence was considered completed when chemotherapy or targeted therapy was used after PRRT failure.