Table 2.
Patient, tumor, and treatment characteristics
| Characteristic | Overall cohort | Weighted cohort | ||||||
|---|---|---|---|---|---|---|---|---|
| All patients (n = 200) |
BED >70 Gy (n = 47) |
BED ≤70 Gy (n = 153) |
P | Std diff (%) |
BED >70 Gy | BED ≤70 Gy | Std diff (%) |
|
| Patient characteristics | ||||||||
| Age (y), median (range) | 64 (37–88) | 64 (38–82) | 64 (37–88) | .92 | 66 (38–82) | 64 (37–87) | ||
| Age (y), n (%) | .60 | 8.75 | 0.66 | |||||
| >60 | 134 (67) | 30 (64) | 104 (68) | (68) | (68) | |||
| ≤60 | 66 (33) | 17 (36) | 49 (32) | (32) | (32) | |||
| Gender, n (%) | .63 | 8.14 | 0.50 | |||||
| Male | 113 (57) | 28 (60) | 85 (56) | (56) | (56) | |||
| Female | 87 (44) | 19 (40) | 68 (44) | (44) | (44) | |||
| Race, n (%) | .17 | 24.11 | 12.67 | |||||
| White | 146 (73) | 38 (81) | 108 (71) | (67) | (73) | |||
| Other | 54 (27) | 9 (19) | 45 (29) | (33) | (27) | |||
| KPS, n (%) | .45 | 15.25 | 1.05 | |||||
| ≥80 | 174 (88) | 43 (91) | 131 (87) | (88) | (88) | |||
| <80 | 24 (12) | 4 (9) | 20 (13) | (12) | (12) | |||
| Baseline CA19-9 (U/mL), median (range) | 198 (1–12,440) | 355 (1–4999) | 178 (1–12,440) | .2 | 363 (1–4999) | 183 (1–12,440) | ||
| % Weight loss, median (range) | 9.04 (0–34.97) | 7.85 (0–34.97) | 9.62 (0–29.7) | .05 | 9.04 (0–34.97) | 8.98 (0–29.70) | ||
| Weight loss, n (%) | .05 | 34.62 | 3.89 | |||||
| >10% | 88 (46) | 14 (33) | 74 (49) | (46) | (44) | |||
| ≤10% | 105 (54) | 29 (67) | 76 (51) | (54) | (56) | |||
| Baseline hemoglobin (g/dL), median (range) | 12.85 (8.2–18) | 13.15 (10.3–16.3) | 12.8 (8.2–18) | .59 | 12.3 (10.3–16.3) | 12.9 (8.2–18) | ||
| Baseline hemoglobin (g/dL), n (%) | .25 | 19.98 | 10.35 | |||||
| >12 | 133 (69) | 35 (76) | 98 (67) | (65) | (70) | |||
| ≤12 | 59 (31) | 11 (24) | 48 (33) | (35) | (30) | |||
| Tumor characteristics | ||||||||
| Tumor size (cm), median (range) | 3.5 (0.9–8) | 3.2 (0.9–8) | 3.6 (0.9–7.5) | .16 | 3.2 (0.9–8) | 3.6 (0.9–7.5) | ||
| Tumor location, n (%) | .26 | 19 | 6.04 | |||||
| Head | 118 (61) | 24 (53) | 94 (63) | (64) | (61) | |||
| Other | 77 (39) | 21 (47) | 56 (37) | (36) | (39) | |||
| Treatment characteristics | ||||||||
| Induction chemotherapy, n (%)* | .04 | 33.51 | 0.71 | |||||
| Gemcitabine-based | 158 (79) | 32 (68) | 126 (82) | (79) | (79) | |||
| FOLFIRINOX | 42 (21) | 15 (32) | 27 (18) | (21) | (21) | |||
| Concurrent chemotherapy, n (%)† | .16‡ | 22.74‡ | 3.08‡ | |||||
| 5-Fluorouracil | 3 (2) | 1 (2) | 2 (1) | (2) | (1) | |||
| Vorinostat | 1 (1) | 1 (2) | 0 (0) | (2) | (0) | |||
| Gemcitabine-based | 24 (12) | 7 (16) | 17 (11) | (12) | (13) | |||
| Capecitabine-based | 167 (86) | 34 (79) | 133 (88) | (84) | (86) | |||
| Biologically effective dose, median (range) | 59.47 (29.74–100) | 83.11 (70.36–100) | 59.47 (29.74–60) | 83.44 (70.36–100) | 59.47 (29.74–60) | |||
| Radiation technique | <.001 | |||||||
| IMRT | 58 (29) | 45 (96) | 13 (9) | (97) | (9) | |||
| Conventional 3D conformal | 141 (70) | 1 (2) | 140 (91) | (1) | (91) | |||
| IMRT + proton boost | 1 (1) | 1 (2) | 0 (0) | (2) | (0) | |||
| Change in CA 19-9 after induction chemotherapy, median (range) | 34.08 (−20,380 to 99.36) | 41.37 (−41.93 to 96.38) | 34.08 (−20,380 to 99.36) | .51 | 53.65 (−41.93 to 96.38) | 34.74 (−20,380 to 99.36) | ||
| Change in CA 19-9 after induction chemotherapy, n (%) | 1 | 0 | 0.04 | |||||
| >34 | 81 (50) | 13 (50) | 68 (50) | (50) | (50) | |||
| ≤34 | 81 (50) | 13 (50) | 68 (50) | (50) | (50) | |||
Abbreviations: BED = biologically effective dose; IMRT = intensity modulated radiation therapy; KPS = Karnofsky performance status; Std diff = standardized difference.
Gemcitabine-based induction therapy consisted of gemcitabine alone or in combination with paclitaxel, cisplatin, oxaliplatin, erlotinib, bevacizumab, or cetuximab.
Gemcitabine-based concurrent therapy consisted of gemcitabine alone or in combination with erlotinib; capecitabine-based concurrent therapy consisted of capecitabine alone or in combination with bevacizumab, erlotinib, or cetuximab; where numbers do not add to 200, insufficient data were available in remaining patients.
Calculated when concurrent chemotherapy was dichotomized as capecitabine versus others.