Table 2.
Univariable and multivariable logistic regression model to identify covariates associated with CTCAE late genitourinary toxicity after SBRT.
| Covariates | Level | CTCAE Grade 2+ GU Late Toxicity (6–24 Months) | CTCAE Persistent Grade 2+ GU Late Toxicity | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| No (n = 282) |
Yes (n = 132) |
Univariable | Multivariable (n = 404) |
No (n = 341) |
Yes (n = 73) |
Univariable | Multivariable (n = 404) |
||||||
| N (%) or Median (IQR) |
N (%) or Median (IQR) |
OR (95% CI) |
p value |
OR (95% CI) |
p value |
N (%) or Median (IQR) |
N (%) or Median (IQR) |
OR (95% CI) |
p value |
OR (95% CI) |
p value |
||
| Baseline grade 2+ GU symptoms |
No Yes Missing |
275 (98) 5 (2) 2 |
116 (88) 16 (12) 0 |
7.59 (2.72-21.19) | <0.0001 | 4.27 (1.41-13.04) |
0.01 | 332 (98) 7 (2) 2 |
58 (81) 14 (19) 0 |
11.25 (4.36-29.1) | <0.0001 | 5.95 (2.1-16.9) | 0.001 |
| Baseline IPSS score |
Median (n) |
5 (3-10) (n=243) |
8 (4-14) (n=114) |
1.09(1.05-1.13) | <0.0001 | 5 (3-11) (n=295) |
7.5 (4-15) (n=62) |
1.07 (1.03-1.12) | 0.002 | ||||
| Baseline EPIC-26 overall urinary bother score |
Median (n) |
100 (75-100) (n=264) |
75 (50-100) (n=119) |
0.98 (0.97-0.99) | <0.0001 | 100 (75-100) (n=316) |
75 (50-100) (n=67) |
0.98 (0.97-0.99) | <0.0001 | ||||
| Worst acute grade 2+ GU Toxicity |
No Yes |
224 (79) 58 (21) |
60 (45) 72 (55) |
4.63 (2.96-7.25) | <0.0001 | 3.70 (2.39-5.98) | <0.0001 | 258 (76) 83 (24) |
26 (36) 47 (64) |
5.62 (3.28-9.63) | <0.0001 | 4.26 (2.36-7.68) | <0.0001 |
| Persistent acute grade 2+ GU toxicity |
No Yes |
261 (93) 21 (7) |
91 (69) 41 (31) |
5.60(3.14-9.98) | <0.0001 | 314 (92) 27 (8) |
38 (52) 35 (48) |
10.71 (5.85-19.60) | <0.0001 | ||||
| Worst acute IPSS score |
Median (n) | 12 (8-18) (n=273) |
17 (11-23) (n=173) |
1.07(1.04-1.11) | <0.0001 | 13 (8-18) (n=332) |
16.5 (11-24) (n=70) |
1.06 (1.03-1.10) | <0.0001 | ||||
| Worst acute EPIC-26 overall urinary bother score |
Median (n) |
75(50-100) (n=275) |
50 (25-75) (n=126) |
0.98 (0.97-0.99) | <0.0001 | 75(50-100) (n=331) |
50 (25-75) (n=70) |
1.77 (1.00-3.16) | 0.05 | ||||
| Worst acute urinary symptoms Grade 2+ Obstructive Grade 2+ irritative Grade 2+ pain/dysuria Grade 2+ Incontinence Grade 1+ haematuria |
No Yes No Yes No Yes No Yes No Yes |
270 (96) 12 (4) 242 (86) 40 (14) 264 (94) 18 (6) 280 (99) 2 (1) 256 (91) 26 (9) |
107 (82) 24 (18) 79 (60) 53 (40) 106 (81) 25 (19) 120 (92) 11 (8) 117 (89) 14 (11) |
5.04 (2.43-10.5) 4.06 (2.50-6.58) 3.46 (1.81-6.60) 12.8 (2.80-58.78) 1.18 (0.59-2.34) |
<0.0001 <0.0001 <0.0001 0.001 0.639 |
325 (96) 15 (4) 282 (83) 59 (17) 313 (92) 27 (8) 337 (99) 3 (1) 307 (90) 33 (10) |
52 (71) 21 (29) 39 (53) 34 (47) 57 (78) 16 (22) 63 (86) 10 (14) 66 (90) 7 (10) |
8.75(4.24-18.06) 4.17 (2.43-7.14) 3.25 (1.65-6.24) 17.8 (4.77-66.3) 0.99 (0.42-2.33) |
<0.0001 <0.0001 0.001 <0.0001 0.98 |
||||
| Age | Median (n) |
69 (65-73) (n=282) |
70 (66-74) (n=132) |
1.02 (0.99-1.06) | 0.15 | 1.01 (0.97-1.05) | 0.59 | 69 (65-73) (n=341) |
69 (67-73) (n=73) |
1.01 (0.98-1.05) | 0.47 | ||
| Prostate Volume (cm3) |
Median (n) |
39 (30-54) (n=278) |
44 (34-61) (n=131) |
1.01 (1.00-1.03) | 0.02 | 1.01 (0.99-1.02) | 0.36 | 40 (31-55) (n=337) |
47 (33-62) (n=72) |
1.01 (1.00-1.02) |
0.05 | 1.00 (0.99-1.02) | 0.50 |
| Risk group (intermediate) |
low Int |
23 (8) 259 (92) |
12 (9) 120 (91) |
0.89 (0.43-1.84) | 0.75 | 29 (8) 312 (92) |
6 (8) 67 (92) |
1.04 (0.41-2.60) | 0.08 | ||||
| Baseline urinary medication (Yes) |
No Yes |
228 (81) 54 (19) |
99 (75) 33 (25) |
1.41 (0.86-2.30) | 0.17 | 277 (81) 64 (19) |
50 (69) 23 (31) |
1.99 (1.13-3.49) | 0.017 | 1.79 (0.94-3.40) | 0.08 | ||
| SBRT modality (CL) | CK CL Other/ missing |
130 (46) 151 (54) 1 |
39 (30) 90 (68) 3 |
1.99 (1.28-3.09) | 0.002 | 2.30 (1.34-3.94) | 0.002 | 148 (44) 192 (56) 1 |
21 (29) 49 (67) 3 |
1.80 (1.03-3.13) | 0.04 | 1.89 (0.98-3.68) | 0.06 |
| Fiducial use (Yes) | No Yes |
83 (29) 199 (71) |
28 (21) 104 (79) |
1.55 (0.95-2.53) | 0.08 | 2.44 (1.35-4.40) | 0.002 | 98 (29) 243 (71) |
13 (18) 60 (82) |
1.86 (0.98-3.54) | 0.06 | 2.41 (1.14-5.11) | 0.02 |
OR = odds ratio; IQR = interquartile range; CL = conventional linac; GU = genitourinary; IPSS = international Prostate Symptom Score; EPIC = Expanded Prostate Cancer Index Composite; CK = CyberKnife; Int = Intermediate.