Table 2.
Correlation of baseline ctDNA fraction and PSA kinetics.
| ctDNA Low (<0.180) | ctDNA High (≥0.180) | p | |
|---|---|---|---|
| Baseline PSA (ng/mL) (IQR) | 20.64 (9.25 to 95.0) | 51.79 (13.79 to 158.0) | 0.011 |
| PSA response rate (yes vs. no), n (%) | 43 (63.2) vs. 25 (36.8) | 29 (42.7) vs. 39 (57.3) | 0.017 |
| Maximum % PSA decline (IQR) | −80.92 (−92.74 to −54.48) | −63.11 (−98.23 to −31.94) | 0.134 |
| PSA response rate at week 12 (>30%), n (%) | 45 (83.3) vs. 9 (16.7) | 34 (75.6) vs. 11 (24.4) | 0.340 |
| PSA response rate at week 12 (>50%), n (%) | 41 (75.9) vs. 13 (24.1) | 28 (62.2) vs. 17 (37.8) | 0.142 |
| PSA response rate at week 12 (>90%), n (%) | 18 (33.3) vs. 36 (66.7) | 8 (17.8) vs. 37 (82.2) | 0.081 |
| Nadir PSA value (ng/mL) (IQR) | 3.62 (1.23 to 17.00) | 21.77 (2.69 to 57.32) | 0.0008 |
| Time to PSA nadir (months) (IQR) | 3.68 (1.81 to 7.34) | 1.84 (0.92 to 3.39) | 0.012 |
| PSA nadir DT (months) (IQR) | −2.26 (−3.81 to −1.00) | −1.39 (−3.15 to −0.77) | 0.007 |
| PSA DT velocity from baseline to nadir (ng/mL/month) (IQR) | −2.90 (−1.46 to −11.30) | −11.53 (−2.89 to −2.28) | 0.034 |
| PSA DT from nadir (months) (IQR) | 3.80 (2.20–6.20) | 2.50 (1.60–3.80) | 0.024 |
| PSA DT velocity from nadir (ng/mL/month) (IQR) | 3.30 (0.9–13.8) | 14.3 (2.7–81.4) | 0.0002 |
| Time to PSA PD (months) (IQR) | 9.11 (4.87 to 16.10) | 3.78 (2.76 to 7.00) | <0.0001 |
Abbreviations. DT, double timing; IQR, interquartile range; PD, progression disease; PSA, prostate specific antigen; ctDNA, circulating tumour DNA.