Background
Methods
Selection of patients
All patients | |
---|---|
N = 180 | |
Age (median [range]) years | 70.5 [49.6–84.9] |
T stage-n (%) | |
T1c | 57 (31.7 %) |
T2a | 31 (17.2 %) |
T2b | 37 (20.6 %) |
T2c | 19 (10.6 %) |
T3a | 30 (16.7 %) |
T3b | 6 (3.3 %) |
PSA (ng/ml) (median [range]) | 10 [0.8–99] |
Gleason score-n (%) | |
≤ 6 | 103 (57.2 %) |
7 | 64 (35.6 %) |
≥ 8 | 13 (7.2 %) |
Risk groups-n (%) | |
Low risk | 48 (26.7 %) |
Intermediate risk | 68 (37.8 %) |
High risk | 64 (35.6 %) |
Hormone therapy-n (%) | |
Neoadjuvant | 50 (27.8 %) |
Concomitant | 69 (38.3 %) |
Adjuvant | 70 (38.9 %) |
Radiotherapy: prostate dose (2Gy/fxa) | 78 [70–80] |
Median [range] | |
TURPb-n (%) | |
Yes | 35 (19.7 %) |
No | 143 (80.3 %) |
Missing | 2 (1.1 %) |
IMRT
IGRT
Dose/volume modeling for rectal toxicity
Calculation of the area under the rectum DVH curve (rAUC)
Follow-up and toxicity evaluation
Statistical analyses
Results
Characterization of toxicity
Predictors of acute GI toxicity
Median [range] | All patients | Patients with acute toxicities Gb = 0 | Patients with acute toxicities G ≥ 1 |
p-value |
---|---|---|---|---|
n = 180 |
n = 63 |
n = 117 | ||
Rectum volumes expressed in % | ||||
V25a
| 68 [27;100] | 69.6 [27;100] | 67.7 [31.6;100] | 0.799 |
V30 | 60.9 [24.2;100] | 61.6 [24.2;100] | 60.7 [25.5;100] | 0.860 |
V35 | 51.9 [21;100] | 51.7 [21.8;99.6] | 52.1 [21;100] | 0.726 |
V40 | 44 [17.6;96.7] | 44.3 [19.7;85.3] | 43.9 [17.6;96.7] | 0.638 |
V45 | 35.2 [13.1;82.2] | 37.1 [15.5;62.8] | 34.8 [13.1;82.2] | 0.704 |
V50 | 27.8 [8;74.6] | 28.3 [9.3;52.9] | 27.7 [8;74.6] | 0.766 |
V55 | 22.4 [5.4;51.2] | 23 [5.4;43.6] | 22.3 [6.1;51.2] | 0.875 |
V60 | 17.2 [2.7;40.8] | 17.6 [2.7;35.1] | 17 [3.4;40.8] | 0.918 |
V65 | 11.8 [1;29.5] | 12.6 [1;29.5] | 11.5 [1.2;26.5] | 0.582 |
V70 | 7.3 [0;23.1] | 7.8 [0;23.1] | 6.7 [0;19.8] | 0.217 |
V75 | 0.9 [0;11.4] | 1.5 [0;11.4] | 0.7 [0;9.1] | 0.124 |
Rectum volumes expressed in cc | ||||
V25 | 53.5 [20.1;223] | 48.8 [20.1;114] | 57 [20.6;223] | 0.039 |
V30 | 47.5 [19.5;180.2] | 42.8 [19.5;99.8] | 50.9 [19.8;180.2] | 0.045 |
V35 | 41.7 [16.7;150] | 37.8 [16.7;86] | 42.6 [17.4;150] | 0.035 |
V40 | 36.1 [11;120.8] | 31.9 [11;79] | 37.4 [13.9;120.8] | 0.025 |
V45 | 29.8 [8;101.9] | 25.8 [8;69.1] | 31.6 [10.2;101.9] | 0.018 |
V50 | 24.1 [5.9;77] | 21.1 [5.9;58.1] | 25 [7.6;77] | 0.035 |
V55 | 19 [4.4;56.4] | 17.9 [4.4;47.8] | 19.7 [5.8;56.4] | 0.069 |
V60 | 14.6 [2.4;43.6] | 13.1 [2.4;36.3] | 15.2 [3.1;43.6] | 0.17 |
V65 | 10.2 [0.9;36.8] | 9.9 [0.9;28.7] | 11 [1.3;36.8] | 0.387 |
V70 | 5.7 [0;29.5] | 5.8 [0;20.2] | 5.7 [0;29.5] | 0.853 |
V75 | 0.8 [0;16.2] | 0.9 [0;8] | 0.6 [0;16.2] | 0.232 |
rAUC25–50 (cc. Gy)
c
| 972.5 [388.5;3305.3] | 835.7 [394.3;2008.8] | 1002.4 [388.5;3305.3] | 0.028 |
Univariate analysis | Multivariate analysis | Bootstrapping (170 rep) | ||||||||
---|---|---|---|---|---|---|---|---|---|---|
Acute GIa toxicity G ≥ 1 / N | ORc
| 95 % CId
|
p-value | Acute GI toxicity G ≥ 1 / N | OR | 95 % CI |
p-value | 95 % CI |
p-value | |
115/178 | ||||||||||
rAUC25-50
b rectum | ||||||||||
Liu/Youden cutting methods | ||||||||||
< =794 cc.Gy | 29/59 | 1 | 0.002 | 28 / 58 | 1 | 0.020 | 0.019 | |||
> 794 cc.Gy | 88/121 | 2.76 | [1.44;5.28] | 87 / 120 | 2.51 | [1.16;5.46] | [1.16;5.42] | |||
Adjustment variables | ||||||||||
Age | ||||||||||
< 70 years | 57/82 | 1 | 0.247 | 57 / 82 | 1 | 0.233 | 0.226 | |||
> = 70 years | 60/ 98 | 0.69 | [0.37;1.29] | 58 / 96 | 0.67 | [0.35;1.29] | [0.35;1.28] | |||
TURPe
| ||||||||||
No | 95/143 | 1 | 0.305 | 95 / 143 | 1 | 0.423 | 0.459 | |||
Yes | 20/35 | 0.67 | [0.32;1.43] | 20 / 35 | 0.72 | [0.33;1.59] | [0.31;1.7] | |||
HTf
| ||||||||||
No | 65/104 | 1 | 0.411 | 64 / 103 | 1 | 0.757 | 0.755 | |||
Yes | 52/76 | 1.3 | [0.7;2.43] | 51 / 75 | 1.11 | [0.57;2.16] | [0.57;2.15] | |||
Rectum Volume (cc) per unit | 1 | 0.041 | 1 | 0.558 | 0.570 | |||||
1.01 | [1;1.02] | 1 | [0.99;1.01] | [0.99;1.01] |