Table 1.
Demographics of patients with detectable or undetectable ctDNA
| Characteristic | Total | Undetectable ctDNA | Detectable ctDNA |
|---|---|---|---|
| N (%) | N (%) | N (%) | |
| Age in years, median (range) | 52 (19–87) | 52 (19–79) | 59 (22–87) |
| P value | 0.29 | ||
| Gender | |||
| Male | 77 (48) | 70 (49) | 7 (37) |
| Female | 84 (52) | 72 (51) | 12 (63) |
| P value | 0.31 | ||
| Breslow of primary tumor | |||
| ≤2.0 mm | 61 (38) | 53 (37) | 8 (42) |
| >2–4.0 mm | 49 (30) | 43 (30) | 6 (32) |
| >4.0 mm | 42 (26) | 38 (27) | 4 (21) |
| Unknown | 9 (6) | 8 (6) | 1 (5) |
| P value | 0.96 | ||
| Ulceration of primary tumor | |||
| Present | 63 (39) | 57 (40) | 6 (32) |
| Absent | 77 (48) | 69 (49) | 8 (42) |
| Unknown | 21 (13) | 16 (11) | 5 (26) |
| P value | 0.19 | ||
| Disease stage | |||
| II | 36 (22) | 33 (23) | 3 (16) |
| IIIA | 29 (18) | 27 (19) | 2 (11) |
| IIIB | 59 (37) | 51 (36) | 8 (42) |
| IIIC | 37 (23) | 31 (22) | 6 (32) |
| P value | 0.61 | ||
| Nodal classification | |||
| II (No or N/A) | 36 (22) | 33 (23) | 3 (16) |
| III (N1a and N2a) | 41 (26) | 36 (25) | 5 (26) |
| III (other N) | 84 (52) | 73 (52) | 11 (58) |
| P value | 0.81 | ||
| ECOG PS | |||
| 0 | 138 (86) | 125 (89) | 13 (68) |
| 1 | 22 (14) | 16 (11) | 6 (32) |
| P value | 0.03 | ||
| Mutation status | |||
| BRAF V600E | 132 (82) | 117 (82) | 15 (79) |
| NRAS Q61K/L | 29 (18) | 25 (18) | 4 (21) |
| P value | 0.75 | ||
| Trial arm | |||
| Bevacizumab | 81 (50) | 71 (50) | 10 (53) |
| Observation | 80 (50) | 71 (50) | 9 (47) |
| P value | 0.83 | ||
| Total | 161 (100) | 142 (88) | 19 (12) |
ctDNA, circulating tumor DNA; ECOG PS, Eastern Cooperative Oncology Group performance status; N, number.
P values were obtained using the Wilcoxon rank sum test for continuous factors and a chi-square test or Fisher's exact test with small number for categorical factors.