Table 4. Logistic Regression Model for Estimating Associations Between Risk Factors and Pathological Complete Response.
| Variable | No. of patients (N = 1695) | Univariable analysis | Multivariable analysis | ||
|---|---|---|---|---|---|
| OR (95% CI) | P value | OR (95% CI) | P value | ||
| Gender | |||||
| Female | 850 | 1 [Reference] | NA | NA | NA |
| Male | 845 | 1.12 (0.71-1.75) | .63 | NA | NA |
| Tumor location | |||||
| Body or tail | 462 | 1 [Reference] | NA | 1 [Reference] | NA |
| Head | 1233 | 1.98 (1.08-3.63) | .03 | 2.51 (1.25-5.06) | .01 |
| Tumor size at diagnosis, mm | |||||
| ≤20 | 376 | 1 [Reference] | NA | 1 [Reference] | NA |
| 21-40 | 1073 | 2.03 (0.99-4.17) | .05 | 1.52 (0.69-3.33) | .29 |
| >40 | 246 | 3.61 (1.62-8.06) | .002 | 2.58 (1.03-6.48) | .04 |
| Resectability at diagnosis | |||||
| Primary resectable | 424 | 1 [Reference] | NA | 1 [Reference] | NA |
| Borderline resectable | 827 | 3.54 (1.49-8.42) | .004 | 1.63 (0.60-4.40) | .34 |
| Locally advanced | 444 | 5.78 (2.40-13.91) | <.001 | 2.31 (0.84-6.36) | .10 |
| CA 19-9 at diagnosis, U/mL | |||||
| <37 | 307 | 1 [Reference] | NA | NA | NA |
| ≥37 to <150 | 331 | 0.99 (0.48-2.04) | .98 | NA | NA |
| ≥150 to <500 | 348 | 0.40 (0.16-0.99) | .05 | NA | NA |
| ≥500 to <1000 | 148 | 0.82 (0.31-2.16) | .69 | NA | NA |
| ≥1000 | 252 | 0.64 (0.27-1.53) | .31 | NA | NA |
| Missing | 309 | 1.94 (1.01-3.71) | .05 | NA | NA |
| Preoperative chemotherapy | |||||
| (m)FOLFIRINOX | 771 | 1 [Reference] | NA | 1 [Reference] | NA |
| Other multiagent | 765 | 0.38 (0.22-0.64) | <.001 | 0.48 (0.26-0.87) | .02 |
| Single agent | 159 | 1.20 (0.62-2.32) | .58 | 2.42 (0.99-5.92) | .05 |
| Preoperative radiotherapy | |||||
| None | 845 | 1 [Reference] | NA | 1 [Reference] | NA |
| Conventional radiotherapy | 448 | 3.75 (2.06-6.83) | <.001 | 2.03 (1.00-4.10) | .05 |
| SBRT | 402 | 4.07 (2.22-7.45) | <.001 | 8.91 (4.17-19.05) | <.001 |
| Preoperative therapy duration, mo | |||||
| <4 | 456 | 1 [Reference] | NA | 1 [Reference] | NA |
| ≥4 to <6 | 455 | 1.15 (0.55-2.39) | .71 | 0.59 (0.24-1.46) | .25 |
| ≥6 to <12 | 616 | 1.67 (0.88-3.18) | .12 | 0.63 (0.27-2.45) | .27 |
| ≥12 | 113 | 5.21 (2.46-11.03) | <.001 | 2.13 (0.83-5.43) | .12 |
| Missing | 55 | 1.82 (0.51-6.55) | .36 | 0.99 (0.23-4.23) | .98 |
| RECIST | |||||
| Stable disease | 1165 | 1 [Reference] | NA | 1 [Reference] | NA |
| Progressive disease | 24 | 2.94 (0.37-23.00) | .31 | 1.84 (0.20-17.30) | .59 |
| Partial or complete response | 506 | 9.43 (5.45-16.31) | <.001 | 13.00 (7.02-24.08) | <.001 |
| CA 19-9 at restaging, U/mL | |||||
| ≥37 | 709 | 1 [Reference] | NA | 1 [Reference] | NA |
| <37 (normal[ization]) | 748 | 3.59 (1.82-7.04) | <.001 | 3.76 (1.79-7.89) | <.001 |
| Missing | 238 | 8.80 (4.32-17.92) | <.001 | 10.89 (4.73-25.06) | <.001 |
| Relative CA 19-9 change | |||||
| No change or increased | 86 | 1 [Reference] | NA | NA | NA |
| Decreased <87% | 521 | 0.74 (0.16-3.48) | .70 | NA | NA |
| Decreased ≥87% | 427 | 2.17 (0.50-9.44) | .30 | NA | NA |
| <37 U/mL at diagnosis | 307 | 2.16 (0.48-9.62) | .31 | NA | NA |
| Missing | 354 | 4.32 (1.02-18.36) | .05 | NA | NA |
Abbreviations: CA 19-9, carbohydrate antigen 19-9; (m)FOLFIRINOX, (modified) leucovorin calcium (folinic acid), fluorouracil, irinotecan hydrochloride, and oxaliplatin; NA, not applicable; OR, odds ratio; RECIST, Response Evaluation Criteria in Solid Tumors; SBRT, stereotactic body radiotherapy.