Table 1.
Patient Characteristics
| Characteristic | Recurrence (n = 50) | No Recurrence (n = 94) | P |
|---|---|---|---|
| Age at diagnosis, median (IQR), y | 65.1 (55.7‐73.7) | 62.5 (51.1‐72.3) | .284 |
| Sex: male, No. (%) | 34 (68.0) | 58 (61.7) | .454 |
| Primary cancer, No. (%) | |||
| Stage | |||
| I | 0 (0) | 21 (22.3) | <.001 |
| II | 13 (26.0) | 37 (39.4) | .109 |
| III | 30 (60.0) | 32 (34.8) | .004 |
| IV | 7 (14.0) | 4 (4.4) | .040 |
| Location | |||
| Right colona | 12 (24.0) | 37 (39.4) | .064 |
| Left colon | 16 (32.0) | 30 (31.9) | 1.000 |
| Rectum | 22 (44.0) | 27 (28.7) | .065 |
| T stage | |||
| T1 | 0 (0) | 12 (12.8) | .008 |
| T2 | 2 (4.0) | 14 (14.9) | .048 |
| T3 | 26 (52.0) | 51 (54.3) | .798 |
| T4 | 20 (40.0) | 17 (18.1) | 0004 |
| Tx | 2 (4.0) | 0 (0) | .515 |
| Nature of treatment | |||
| Resection ± adjuvant therapy | 41 (82.0) | 93 (98.9) | <.001 |
| Neoadjuvant therapy only | 9 (18.0) | 1 (1.1) | <.001 |
| Location of recurrence, No. (%) | |||
| Locoregionalb | 13 (26.0) | N/A | N/A |
| Distant | 37 (74.0) | N/A | N/A |
| Time between diagnosis and imaging status, median (IQR), mo | 24.2 (16.1‐35.0) | 18.2 (13.0‐28.9) | .010 |
| Time between proximate blood and imaging status, median (IQR), mo | 2.6 (0.8‐5.5) | 1.4 (0.3‐4.7) | .258 |
| Time between CRC surgery (or rectal neoadjuvant therapy) and blood collection, median (IQR), mo | 18.8 (9.6‐28.0) | 17.3 (11.0‐28.3) | .528 |
| Follow‐up since diagnosis, median (IQR), mo | 47.8 ( 33.7‐61.9) | 46.3 (31.7‐53.3) | .205 |
| Follow‐up after imaging status, median (IQR), mo | 17.1 (9.1‐29.1) | 12.6 (10.9‐17.9) | .102 |
| Follow‐up after blood collection, median (IQR), mo | 18.2 (9.1‐31.5) | 23.7 (12.3‐34.1) | .182 |
Abbreviations: CRC, colorectal cancer; IQR, interquartile range; N/A, not applicable.
a
The right colon included the colon proximal to the splenic flexure.
b
All were rectal cancers clear of residual disease on imaging at the conclusion of neoadjuvant therapy.