Table 1.
Characteristics of the unmatched cohort at the time of radiotherapy.
| Variable | SBRT (n = 95) | CCRT (n = 66) | p value | ASD |
|---|---|---|---|---|
| Age (years) | 64 (38–84) | 60.5 (34–76) | 0.045 | 0.346 |
| Gender | 0.057 | 0.320 | ||
| Male | 49 (51.6%) | 44 (66.7%) | - | - |
| Female | 46 (48.4%) | 22 (33.3%) | - | - |
| ECOG PS | 0.473 | 0.192 | ||
| 0–1 | 89 (93.7%) | 64 (97.0%) | - | - |
| 2 | 6 (6.3%) | 2 (3.0%) | - | - |
| Pre-RT CA19-9 | 0.032 | 0.318 | ||
| ≤37 U/mL | 20 (21.1%) | 24 (36.4%) | - | - |
| >37 U/mL | 75 (79.9%) | 42 (63.6%) | - | - |
| Tumor Location | 0.351 | 0.152 | ||
| Head | 52 (54.7%) | 41 (62.1%) | - | - |
| Body/Tail | 43 (45.3%) | 25 (37.9%) | - | - |
| Tumor Size | <0.001 | 0.982 | ||
| ≤40 mm | 32 (33.7%) | 50 (75.8%) | - | - |
| >40 mm | 63 (66.3%) | 16 (24.2%) | - | - |
| Clinical Node Stage | 0.095 | 0.253 | ||
| N0 | 72 (75.8%) | 42 (63.6%) | - | - |
| N+ | 23 (24.2%) | 24 (36.4%) | - | - |
| Abutting the Stomach/Duodenum | 0.515 | 0.101 | ||
| No | 72 (75.8%) | 47 (71.2%) | - | - |
| Yes | 23 (24.2%) | 19 (28.8%) | - | - |
| Induction Chemotherapy | <0.001 | - | ||
| None | 55 (57.9%) | 6 (9.1%) | - | - |
| ≤6 months | 38 (40.0%) | 43 (65.2%) | - | - |
| >6 months | 2 (2.1%) | 17 (25.7%) | - | - |
| Post-RT Chemotherapy | <0.001 | - | ||
| No | 13 (13.7%) | 50 (75.8%) | - | - |
| Yes | 82 (86.3%) | 16 (24.2%) | - | - |
| RT dose (EQD2, α/β = 10) | 39.7 (31.3–57.0) | 54.0 (40.0–58.4) | <0.001 | - |
Abbreviations: SBRT, stereotactic body radiotherapy; CCRT, concurrent chemoradiotherapy; ASD, absolute standardized difference; ECOG PS, Eastern Cooperative Oncology Group performance status; RT, radiotherapy; CA19-9, carbohydrate antigen 19-9; EQD2, equivalent dose in 2 Gy per fraction. Values are presented as median (range) or number (%) of patients.