TABLE 1.
Clinical Characteristics and Demographics of Patients According to Tumor HER2 Expression (NanoString cohort)
| Patient Characteristic | HER2 Expression (median cutoff) | |||
|---|---|---|---|---|
| High (n = 462) | Low (n = 463) | Total (n = 925) | P | |
| Age, years | .1363 | |||
| N | 462 | 463 | 925 | |
| Median | 61.2 | 59.4 | 60.4 | |
| Q1, Q3 | 53.0, 68.8 | 50.8, 68.9 | 52.1, 68.8 | |
| Treatment arm, No. (%) | .8720 | |||
| A: Bev | 170 (36.8) | 176 (38.0) | 346 (37.4) | |
| B: Cetux | 182 (39.4) | 183 (39.5) | 365 (39.5) | |
| C: Bev + Cetux | 110 (23.8) | 104 (22.5) | 214 (23.1) | |
| Planned protocol chemotherapy, No. (%) | .8287 | |||
| FOLFOX | 357 (77.3) | 355 (76.7) | 712 (77.0) | |
| FOLFIRI | 105 (22.7) | 108 (23.3) | 213 (23.0) | |
| Previous adjuvant chemotherapy, No. (%) | .8378 | |||
| No | 398 (86.1) | 401 (86.6) | 799 (86.4) | |
| Yes | 64 (13.9) | 62 (13.4) | 126 (13.6) | |
| Previous pelvic radiation therapy, No. (%) | .0548 | |||
| No | 437 (94.6) | 423 (91.4) | 860 (93.0) | |
| Yes | 25 (5.4) | 40 (8.6) | 65 (7.0) | |
| Sex, No. (%) | .6091 | |||
| Male | 283 (61.3) | 276 (59.6) | 559 (60.4) | |
| Female | 179 (38.7) | 187 (40.4) | 366 (39.6) | |
| Race, No. (%) | .6835 | |||
| Missing | 4 | 3 | 7 | |
| White | 392 (85.6) | 398 (86.5) | 790 (86.1) | |
| Other | 66 (14.4) | 62 (13.5) | 128 (13.9) | |
| Ethnicity, No. (%) | .4362 | |||
| Hispanic or Latino | 19 (4.1) | 20 (4.3) | 39 (4.2) | |
| Non-Hispanic | 419 (90.7) | 426 (92.0) | 845 (91.4) | |
| Not reported | 2 (0.4) | 0 (0.0) | 2 (0.2) | |
| Unknown | 22 (4.8) | 17 (3.7) | 39 (4.2) | |
| Performance score, No. (%) | .9684 | |||
| 0 | 274 (59.3) | 274 (59.2) | 548 (59.2) | |
| 1 | 188 (40.7) | 189 (40.8) | 377 (40.8) | |
| No. of metastatic sites, No. (%) | .4046 | |||
| Missing | 5 | 4 | 9 | |
| 1 | 233 (51.0) | 242 (52.7) | 475 (51.9) | |
| 2 | 151 (33.0) | 158 (34.4) | 309 (33.7) | |
| 3+ | 73 (16.0) | 59 (12.9) | 132 (14.4) | |
| Liver metastases only, No. (%) | .2483 | |||
| Missing | 5 | 4 | 9 | |
| No | 287 (62.8) | 305 (66.4) | 592 (64.6) | |
| Yes | 170 (37.2) | 154 (33.6) | 324 (35.4) | |
| Tumor location (sidedness), No. (%) | .0919 | |||
| Missing | 18 | 23 | 41 | |
| Left | 275 (61.9) | 248 (56.4) | 523 (59.2) | |
| Right/transverse | 169 (38.1) | 192 (43.6) | 361 (40.8) | |
| Synchronous/metachronous, No. (%) | .5408 | |||
| Missing | 14 | 13 | 27 | |
| Synchronous | 352 (78.6) | 361 (80.2) | 713 (79.4) | |
| Metachronous | 96 (21.4) | 89 (19.8) | 185 (20.6) | |
| BRAF mutation, No. (%) | .0001 | |||
| Missing | 102 | 60 | 162 | |
| Wild-type | 333 (92.5) | 335 (83.1) | 668 (87.5) | |
| Mutant | 27 (7.5) | 68 (16.9) | 95 (12.5) | |
| RAS mutation, No. (%) | .7054 | |||
| Missing | 105 | 62 | 167 | |
| Wild-type | 252 (70.6) | 278 (69.3) | 530 (69.9) | |
| Mutant | 105 (29.4) | 123 (30.7) | 228 (30.1) | |
| MSI status from PCR, No. (%) | .9604 | |||
| Missing | 109 | 83 | 192 | |
| MSI-H | 19 (5.4) | 20 (5.3) | 39 (5.3) | |
| MSI-L | 25 (7.1) | 25 (6.6) | 50 (6.8) | |
| MSS | 309 (87.5) | 335 (88.2) | 644 (87.9) | |
| HER2 gene amplification (FM), No. (%) | .0002 | |||
| Not amplified | 227 (93.8) | 262 (99.6) | 489 (96.8) | |
| Amplified | 15 (6.2) | 1 (0.4) | 16 (3.2) | |
NOTE. Comparisons are between the population with HER2 expression high versus low (median cutoff). P values were generated using Wilcoxon rank-sum tests and Pearson chi-square tests for continuous variables and categorical variables, respectively.
Abbreviations: Bev, bevacizumab; Cetux, cetuximab; FM, foundation medicine; FOLFOX, infusional fluorouracil, leucovorin, and oxaliplatin; FOLFIRI, fluorouracil, leucovorin, and irinotecan; MSI, microsatellite instability; MSS, microsatellite stable; PCR, polymerase chain reaction; Q1,first quartile (ie, 25th percentile); Q3, third quartile (ie, 75th percentile).