TABLE 1.
Comparison of the patient cohort used to compute the initial response prediction models (original FFPE cohort) vs the cohort used for this study (FF cohort)
| Prior cohort FFPE | FF cohort | P value | |
|---|---|---|---|
| N = 81 | N = 81 | ||
| Gender | .870 | ||
| Female | 30 (37.0%) | 28 (34.6%) | |
| Male | 51 (63.0%) | 53 (65.4%) | |
| Age at diagnosis (median ‐ range) | 61 (37 ‐ 81) | 64 (28 ‐ 81) | .129 |
| Primary tumor location: | |||
| Rectal | 20 (24.7%) | 34 (42.0%) | .064 |
| Left sided | 30 (37.0%) | 22 (27.2%) | |
| Right sided | 31 (38.3%) | 25 (30.9%) | |
| Stage | <.001 | ||
| I | 1 (1.20%) | 0 (0.00%) | |
| II | 13 (16.0%) | 0 (0.00%) | |
| III | 12 (14.8%) | 0 (0.00%) | |
| IV | 54 (66.7%) | 81 (100%) | |
| Unknown | 1 (1.20%) | 0 (0.00%) | |
| Differentiation | .943 | ||
| Well/moderately differentiated | 54 (66.7%) | 54 (66.7%) | |
| Poorly differentiated | 15 (18.5%) | 16 (19.8%) | |
| Other | 0 (0.00%) | 1 (1.23%) | |
| Unknown | 12 (14.8%) | 10 (12.3%) | |
| Prior adjuvant therapy | .072 | ||
| Yes | 7 (8.60%) | 16 (19.8%) | |
| No | 74 (91.4%) | 65 (80.2%) | |
| Liver metastases only | <.001 | ||
| No | 57 (70.4%) | 81 (100%) | |
| Yes | 24 (29.6%) | 0 (0.00%) | |
| LDH (cut‐off 250 ng/µL) | <.001 | ||
| Elevated | 55 (67.9%) | 18 (22.2%) | |
| Normal | 23 (28.4%) | 56 (69.1%) | |
| Unknown | 3 (3.70%) | 7 (8.64%) | |
| CEA (cut‐off 5 ng/µL) | |||
| Elevated | 61 (75.3%) | 55 (67.9%) | .643 |
| Normal | 17 (21.0%) | 22 (27.2%) | |
| Unknown | 3 (3.70%) | 4 (4.94%) | |
| First‐line treatment scheme | <.001 | ||
| 5‐FU monotherapy | 14 (17.3%) | 0 (0.00%) | |
| Oxaliplatin‐based regimen | 57 (70.4%) | 81 (100%) | |
| Irinotecan‐based regimen | 10 (12.3%) | 0 (0.00%) | |
| Use of first‐line Bevacizumab | <.001 | ||
| No | 51 (63.0%) | 21 (25.9%) | |
| Yes | 30 (37.0%) | 60 (74.1%) | |
| Best response to first‐line treatment a | |||
| Complete response (CR) | 2 (2.5%) | 0 (0.00%) | .025 |
| Partial response (PR) | 36 (44.4%) | 37 (45.7%) | |
| Stable disease (SD) | 28 (34.6%) | 39 (48.1%) | |
| Progressive disease (PD) | 15 (18.5%) | 5 (6.17%) | |
| Tissue specimen | <.001 | ||
| Primary tumor | 70 (86.4%) | 10 (13.5%) | |
| Metastasis | 11 (13.6%) | 64 (86.5%) |
Data from the original FFPE cohort were adapted from Neerincx et al. 15
Abbreviations: CEA, carcinoembryonic antigen; FF, fresh frozen; FFPE, Formalin‐fixed paraffin‐embedded; LDH, lactate dehydrogenase.
a
According to RECIST 1.1. For the original FFPE cohort best response to first‐line treatment was used as clinical endpoint, while for the FF cohort response after three to four cycles of chemotherapy was used as clinical endpoint in this table.