TABLE 1.
Overall and race‐stratified descriptive characteristics of study cohort
|
Overall cohort N = 840 |
Caucasian American patients n = 572 (68%) |
African American patients n = 268 (32%) |
p‐value | |
|---|---|---|---|---|
| N (%) | N (%) | N (%) | ||
| Age at EBRT, (years) | <0.001 | |||
| Median (IQR a ) | 69.9 (63.8, 74.9) | 70.7 (64.7, 75.5) | 68.4 (62, 73) | |
| Follow‐up time after EBRT, (years) | 0.13 | |||
| Median (IQR) | 6.5 (4.3, 10.9) | 6.9 (4.4, 11.2) | 5.9 (4.2, 10.3) | |
| Time from EBRT to PSA Nadir b , (years) | 0.17 | |||
| Median (IQR) | 2.3 (1.3, 4.3) | 2.2 (1.3, 4.3) | 2.6 (1.4, 4.3) | |
| Time from EBRT to BCR c , (years) | 0.95 | |||
| Median (IQR) | 5.3 (3.4, 7.8) | 5.4 (3.4, 8) | 5 (3.6, 7.5) | |
| Time from EBRT to metastasis, (years) | 0.84 | |||
| Median (IQR) | 8.1 (3.1, 11) | 8.1 (3, 11.2) | 7.1 (3.1, 10.3) | |
| EBRT dosage (centiGrays) | ||||
| Median (IQR) for 3D CRT | 7000 (6840, 7040) | 7000 (6840, 7040) | 7000 (6840, 7020) | 0.70 |
| Median (IQR) for IMRT | 7800 (7600, 7800) | 7800 (7600, 7800) | 7800 (7600, 7800) | 0.37 |
| Prostate gland volume (cc) | 0.80 | |||
| Median (IQR) | 36.5 (28.4, 48.1) | 36.8 (28, 48.1) | 36 (29.7, 48.2) | |
| Primary treatment type, N (%) | 0.53 | |||
| EBRT alone | 748 (89) | 512 (89.5) | 236 (88.1) | |
| EBRT with HT d | 92 (11) | 60 (10.5) | 32 (11.9) | |
| Primary EBRT technique, N (%) | <0.001 | |||
| 3D CRT | 530 (63.1) | 394 (68.9) | 136 (50.7) | |
| IMRT | 310 (36.9) | 178 (31.1) | 132 (49.3) | |
| Secondary HT e , N (%) | 68 (8.1) | 52 (9.1) | 16 (6) | |
| Time from EBRT to secondary HT, (years) Median (IQR) | 6.2 (3.8, 9.4) | 6.2 (3.8, 9) | 7.6 (3.6, 10.3) | 0.73 |
| PSA Nadir (ng/ml), N (%) | ||||
| <0.2 (undetectable) | 241 (29.9) | 165 (30) | 76 (29.6) | 0.90 |
| ≥0.2 (detectable) | 566 (70.1) | 385 (70) | 181 (70.4) | |
| PSA at diagnosis (ng/ml), N (%) | ||||
| Median (IQR) | 5.9 (4.3, 8.3) | 5.8 (4.2, 8.2) | 6.2 (4.5, 8.5) | 0.099 |
| PSADT g (months), N (%) | 0.92 | |||
| <10 | 52 (12.3) | 36 (6.6) | 16 (6.2) | |
| ≥10 | 99 (6.4) | 69 (12.5) | 30 (11.7) | |
| Clinical T stage, N (%) | 0.20 | |||
| ≤T2a | 758 (90.2) | 511 (89.3) | 247 (92.2) | |
| T2b–T2c | 82 (9.8) | 61 (10.7) | 21 (7.8) | |
| Biopsy Gleason score, N (%) | 0.009 | |||
| ≤6 | 691 (82.3) | 484 (84.6) | 207 (77.2) | |
| 3 + 4 | 149 (17.7) | 88 (15.4) | 61 (22.8) | |
| Obese (BMI ≥ 30.0 kg/m2), N (%) | 193 (26.5) | 111 (22.1) | 82 (36.4) | <0.001 |
| Any major comorbidity f , N (%) | 321 (38.2) | 254 (44.4) | 67 (25.0) | <0.001 |
IQR, interquartile range.
PSA nadir was defined as the lowest absolute PSA value following EBRT treatment and prior to secondary HT, if applicable.
BCR, biochemical recurrence, defined as a rise in PSA ≥2 ng/mL above the nadir PSA value.
HT, hormone treatment, defined as any HT within 9 months prior to or 1 year following EBRT treatment (start date).
Secondary HT was defined as HT >1 year following EBRT and before distant metastasis.
Major comorbid conditions included: chronic obstructive pulmonary disease (COPD), cardiovascular disease (CVD), Cerebral Vascular Accident (CVA), and/or other cancer(s).
PSADT, PSA doubling time was calculated among those who experienced a BCR event (n = 151) using all PSA values within 2 years after BCR, censored at the time of metastasis or use of secondary HT. PSADT was then computed as the natural logarithm of 2 divided by the slope obtained from fitting a linear regression of the natural log(PSA)/time.
Bold indicates significant values of p < 0.05.