Table 5.
Univariate and multivariate associations with late grade 3 genitourinary toxicity
|
Variables |
Associated level |
Late grade 3 GU toxicity |
|
|---|---|---|---|
| Hazard ratio (95% CI) | p-value | ||
|
Univariate analysis |
|
|
|
| Age (years) |
Continuous |
1.031 (0.921-1.154) |
0.596 |
| Risk group* |
Intermediate |
0.659 (0.079-5.481) |
0.699 |
| Prostate volume# |
Continuous |
0.928 (0.835-1.032) |
0.170 |
| Number of Applicators |
Continuous |
1.247 (0.906-1.718) |
0.176 |
| PTV volume (cm3) |
Continuous |
1.014 (0.974-1.056) |
0.504 |
| PTV V100 (%) |
Continuous |
>1000 (0.000- > 1000) |
0.371 |
| PTV D90 (Gy) |
Continuous |
83.476 (0.019- > 1000) |
0.301 |
| Urethral volume (cm3) |
Continuous |
41.143 (2.754-614.621) |
0.007 |
| Urethral D1 (Gy) |
Continuous |
6.946 (0.000- > 1000) |
0.692 |
| Urethral V100 (cm3) |
Continuous |
183.29 (6.785- > 1000) |
0.002 |
| Urethral V120 (cm3) |
Continuous |
926.461 (2.653- > 1000) |
0.022 |
| Urethral V125 (cm3) |
Continuous |
405.747 (0.249- > 1000) |
0.111 |
| Acute grade 3 GU toxicity |
Yes |
7.846 (0.876-70.307) |
0.066 |
|
Multivariate analysis |
|
|
|
| Urethral volume (cm3) |
Continuous |
338.940 (9.502- > 1000) |
0.001 |
| Urethral V100 (cm3) |
Continuous |
- |
|
| Urethral V120 (cm3) |
Continuous |
5778.111 (14.398- > 1000) |
0.005 |
| Acute grade 3 GU toxicity | Yes | - | |
Abbreviations: GU genitourinary, PTV planning target volume, PTV V 100 percentage of PTV receiving ≥100% of prescribed dose, D 90 dose administered to 90% of the PTV, Urethral V 100 -V150 absolute urethral volume that received a dose ≥100%, 120%, 125%, 150% of the prescribed dose, Urethral D 1 maximal dose that encompass 1% of the urethral volume, *according to the National Comprehensive Cancer Network (NCCN), #pre-treatment, ADT androgen deprivation therapy.