Table 6.
Patients with one or more displacement of 5 mm in weeks 3–6: univariate and multivariate logistic regression models
| Category* | Data |
Univariate models |
Multivariate models |
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Miss | n | 3 mm+ displacement | OR | (95% CI) | z | P | n | OR | (95% CI) | z | P | |
| T-stage | 2 | 639 | 365 | 1.13 | (0.89, 1.44) | 1.01 | 0.313 | 630 | – | – | – | – |
| Differentiation | 0 | 641 | 366 | 0.80 | (0.58, 1.11) | −1.35 | 0.178 | – | – | – | – | – |
| Age (quartile) | 0 | 641 | 366 | 1.00 | (0.87, 1.16) | 0.06 | 0.953 | – | 0.94 | (0.80, 1.11) | −0.68 | 0.493 |
| Risk group | 0 | 641 | 366 | 1.40 | (1.00, 1.97) | 1.94 | 0.052 | – | 1.21 | (0.81, 1.80) | 0.95 | 0.344 |
| Allocated treatment | 0 | 641 | 366 | 1.06 | (0.78, 1.45) | 0.39 | 0.698 | – | 1.06 | (0.74, 1.52) | 0.31 | 0.755 |
| Dose group | 0 | 641 | 366 | 0.75 | (0.21, 2.61) | −0.46 | 0.649 | – | – | – | – | – |
| Beam modification | 5 | 636 | 363 | 2.99 | (2.09, 4.29) | 5.96 | <0.001 | – | 1.10 | (0.60, 2.00) | 0.3 | 0.765 |
| Treatment verification | 1 | 640 | 366 | 2.94 | (2.10, 4.10) | 6.30 | <0.001 | – | 3.12 | (1.77, 5.48) | 3.95 | <0.001 |
| Phase I fields | 1 | 640 | 366 | 1.31 | (0.95, 1.80) | 1.65 | 0.099 | – | 0.77 | (0.52, 1.13) | −1.33 | 0.185 |
| Fractions imaged | 0 | 641 | 366 | 3.83 | (2.94, 5.00) | 9.92 | <0.001 | – | 1.70 | (1.52, 1.91) | 9.11 | <0.001 |
| Baseline toxicity | 6 | 635 | 366 | 0.88 | (0.64, 1.22) | −0.76 | 0.446 | – | 0.82 | (0.56, 1.19) | −1.05 | 0.294 |
T-stage and differentiation were not included in the multivariate models because they were jointly represented in the risk group.
LMPA, low melting point alloy; MLC, multileaf collimator; EPI, electronic portal imaging.
Category (reference category is depicted in bold): T-stage = T1 vs T2 vs T3; Differentiation = Good vs moderate vs poor (based on differentiation or Gleason sum score, where available); Age = 46–62, 63–66, 67–70, 71 and over; Risk group = Low vs moderate (trial stratification factor); Allocated treatment = 74Gy/37 fractions vs 64 Gy/32 fractions; Beam modification = MLC vs LMPA; Treatment verification = EPI vs film; Phase I fields = three vs four; Total dose = <64Gy vs 64 Gy+; Number of fractions reported = 0–3 vs 4–5 vs 6–8 vs 9+.