Table 1.
Baseline characteristics of the entire patient cohort (n = 86) and the subset of patients (n = 79) who had plasma tested for ctDNA at baseline, subdivided into ctDNA not detected (n = 35) and ctDNA detected (n = 44), and the subset of patients (n = 73) who had plasma tested for ctDNA after one cycle of chemotherapy, subdivided into ctDNA not detected (n = 46) and ctDNA detected (n = 27)
| All patients, n = 86 | Patients with ctDNA detection performed at baseline, n = 79 | Patients with ctDNA detection performed after one cycle of chemotherapy, n = 73 | |||||
|---|---|---|---|---|---|---|---|
| ctDNA not detected, n = 35 | ctDNA detected, n = 44 | p value | ctDNA not detected, n = 46 | ctDNA detected, n = 27 | p value | ||
| Age – median (IQR) | 65.2 (59.0–72.0) | 65.3 (59.5–71.0) | 65.3 (60.6–73.4) | 65.7 (59.3–72.8) | 65.1 (59.5–72.0) | ||
| Sex, n (%) | p = 0.78 | p = 0.02 | |||||
| Female | 14 (16.3) | 5 (14.3) | 8 (18.2) | 3 (6.5) | 7 (25.9) | ||
| Male | 72 (83.7) | 30 (85.7) | 36 (81.8) | 43 (93.5) | 20 (74.1) | ||
| PS at baseline, n (%) | p = 0.7 | p = 0.76 | |||||
| 0 | 51 (59.3) | 19 (54.3) | 28 (63.7) | 29 (63.1) | 15 (55.6) | ||
| 1 | 31 (36.0) | 14 (40.0) | 14 (31.8) | 15 (32.6) | 10 (37.0) | ||
| 2 | 4 (4.7) | 2 (5.7) | 2 (4.5) | 2 (4.3) | 2 (7.4) | ||
| Location of primary tumor, n (%) | p = 0.96 | p = 0.72 | |||||
| Lower esophagus | 22 (25.6) | 8 (22.8) | 10 (22.7) | 11 (23.9) | 15 (55.6) | ||
| GEJ | 54 (62.8) | 23 (65.8) | 28 (63.7) | 31 (67.4) | 10 (37.0) | ||
| Stomach | 10 (11.6) | 4 (11.4) | 6 (13.6) | 4 (8.7) | 2 (7.4) | ||
| Clinical tumor stage, n (%) | p = 0.004 | p = 0.1 | |||||
| cT1/T2 | 25 (29.1) | 17 (48.6) | 5 (11.4) | 18 (39.2) | 6 (22.2) | ||
| cT3/T4 | 60 (69.7) | 16 (45.7) | 39 (88.6) | 26 (56.5) | 21 (77.8) | ||
| cTx | 1 (1.2) | 2 (5.7) | 0 (0.0) | 2 (4.3) | 0 (0.0) | ||
| Clinical nodal stage, n (%) | p = 0.03 | p = 0.08 | |||||
| cN0 | 56 (65.1) | 27 (77.1) | 24 (54.5) | 34 (73.9) | 14 (51.9) | ||
| cN + | 29 (33.7) | 7 (20.0) | 20 (45.5) | 11 (23.9) | 13 (48.1) | ||
| cNx | 1 (1.2) | 1 (2.9) | 0 (0.0) | 1 (2.2) | 0 (0.0) | ||
|
Metastasis stage, n (%) |
– | – | |||||
| cM0 | 81 (94.2) | 32 (91.4) | 44 (100.0) | 42 (91.3) | 26 (96.3) | ||
| cM1 | 1 (1.2) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 1 (3.7) | ||
| cMx | 4 (4.6) | 3 (8.6) | 0 (0.0) | 4 (8.7) | 0 (0.0) | ||
| Lauren classification, n (%) | p = 0.7 | 0.86 | |||||
| Intestinal type | 66 (76.7) | 25 (71.5) | 35 (79.5) | 35 (76.1) | 21 (77.8) | ||
| Diffuse type | 11 (12.8) | 6 (17.1) | 4 (9.1) | 6 (13.0) | 3 (11.1) | ||
| Mixed type | 8 (9.3) | 4 (11.4) | 4 (9.1) | 4 (8.7) | 3 (11.1) | ||
| Unknown | 1 (1.2) | 0 (0.0) | 1 (2.3) | 1 (2.2) | 0 (0.0) | ||
| Signet cell carcinoma in > 50% of cells, n (%) | p = 0.9 | - | |||||
| Yes | 2 (2.3) | 1 (2.9) | 1 (2.3) | 0 (0.0) | 0 (0.0) | ||
| No | 81 (94.2) | 33 (94.2) | 41 (93.2) | 45 (97.8) | 25 (92.6) | ||
| Unknown | 3 (3.5) | 1 (2.9) | 2 (4.5) | 1 (2.2) | 2 (7.4) | ||
| HER2 status, n (%) | p = 0.01 | p = 0.3 | |||||
| Normal | 53 (61.6) | 27 (77.2) | 22 (50.0) | 32 (69.5) | 15 (55.6) | ||
| Positive | 31 (36.1) | 6 (17.1) | 22 (50.0) | 13 (28.3) | 12 (44.4) | ||
| No assessment | 2 (2.3) | 2 (5.7) | 0 (0.0) | 1 (2.2) | 0 (0.0) | ||
| MMR-status, n (%) | p = 0.97 | p = 0.77 | |||||
| Proficient | 81 (94.2) | 33 (94.3) | 41 (93.2) | 44 (95.7) | 24 (88.9) | ||
| Deficient | 1 (1.2) | 0 (0.) | 1 (2.3) | 0 (0.0) | 1 (3.7) | ||
| No assessment | 4 (4.6) | 2 (5.7) | 2 (4.5) | 2 (4.3) | 2 (7.4) | ||
The association between the variables was examined using a Chi-square test for independence
ctDNA circulating tumor DNA; IQR interquartile range; PS WHO performance score; GEJ gastroesophageal junction; HER2 human epidermal growth factor receptor 2; MMR DNA mismatch repair