Table 3.
Subgroup Analysis of Potential Heterogeneity Factors for Acute and Late GU Toxicity.
| Heterogeneity factors | Acute GU toxicity | Late GU toxicity | ||||||
|---|---|---|---|---|---|---|---|---|
| No. Studies | Hazard ratio (95 % CI, P value) |
P Value for Interaction |
I2 | No. Studies | Hazard ratio (95 % CI, P value) |
P Value for Interaction |
I2 | |
| Imaging technology | ||||||||
| 2D imaging + FMs | 2 | 0.81 (0.62–1.05; P = 0.11) | P = 0.28 | 22.1 % | 1 | 0.71 (0.54–0.93; P = 0.01) | P = 0.28 | 22.4 % |
| 3D imaging | 4 | 0.84 (0.70–1.01; P = 0.07) | 4 | 0.82 (0.47–1.42; P = 0.47) | ||||
| Mixed use | 2 | 0.65 (0.51–0.84; P < 0.001) | 3 | 1.46 (0.62–3.44; P = 0.38) | ||||
| Reduced margins in IGRT | ||||||||
| Yes | 6 | 0.87 (0.73–1.03; P = 0.10) | P = 0.07 | 69.9 % | 4 | 0.85 (0.59–1.21; P = 0.36) | P = 0.59 | 0 % |
| No | 3 | 0.69 (0.58–0.82; P < 0.001) | 4 | 0.69 (0.35–1.35; P = 0.28) | ||||
| Radiotherapy volume | ||||||||
| PORT | 6 | 0.74 (0.65–0.85; P < 0.001) | P = 0.12 | 59.5 % | 6 | 0.90 (0.55–1.48; P = 0.68) | P = 0.95 | 0 % |
| WPRT for high risk | 3 | 0.96 (0.72–1.28; P = 0.77) | 3 | 0.87 (0.34–2.26; P = 0.78) | ||||
| Dose escalation in IGRT | ||||||||
| Yes | 3 | 1.01 (0.80–1.27; P = 0.96) | P = 0.02 | 83 % | 3 | 0.81 (0.49–1.34; P = 0.42) | P = 0.69 | 0 % |
| No | 6 | 0.72 (0.62–0.83; P < 0.001) | 5 | 0.69 (0.37–1.28; P = 0.24) | ||||
| Radiotherapy technology | ||||||||
| 3D-CRT | 1 | 0.91 (0.29–2.91; P = 0.88) | P = 0.17 | 44.2 % | 1 | 1.04 (0.10–11.12; P = 0.97) | P = 0.90 | 0 % |
| IMRT or Arc | 4 | 0.67 (0.54–0.83; P < 0.001) | 4 | 0.90 (0.33–2.41; P = 0.83) | ||||
| Mixed use | 4 | 0.86 (0.74–1.00; P = 0.04) | 3 | 0.73 (0.45, 1.19; P = 0.20) | ||||
Abbreviations: GU = genitourinary; FMs = fiducial markers; IGRT = image-guided radiotherapy; WPRT = whole-pelvic radiotherapy; PORT = prostate-only radiotherapy; 3D-CRT = three-dimensional conformal radiotherapy; IMRT = intensity-modulated radiation therapy; Arc = volumetric modulated arc therapy.