Table 2.
Univariate associations with acute toxicity
| Covariate | Acute GU | P valuea,b | Acute GI | P valuea,b | ||||
|---|---|---|---|---|---|---|---|---|
| 0 n = 22 (%) |
1 n = 40 (%) |
2 n = 60 (%) |
0 n = 44 (%) |
1 n = 39 (%) |
2 n = 39 (%) |
|||
| Treatment | <.001a | <.001a | ||||||
| IMRT | 6 (9) | 18 (25) | 47 (66) | 13 (18.3) | 26 (36.6) | 32 (45.1) | ||
| VMAT | 16 (31) | 22 (43) | 13 (25) | 31 (60.8) | 13 (25.5) | 7 (13.7) | ||
| T stage | .036a | .457a | ||||||
| T1 | 9 (11.5) | 26 (33.4) | 43 (55.1) | 25 (32) | 27 (34.6) | 26 (33.4) | ||
| T2/T3 | 13 (29.5) | 14 (31.8) | 17 (38.6) | 19 (43.2) | 12 (27.4) | 13 (29.6) | ||
| Region treated | .006a | .787a | ||||||
| Prostate only | 7 (9.5) | 29 (39.2) | 38 (51.4) | 25 (33.8) | 25 (33.8) | 24 (32.4) | ||
| Prostate + LNs | 15 (31) | 11 (22.9) | 22 (45.8) | 19 (39.6) | 14 (29.2) | 15 (31.3) | ||
| Risk group | .434b | .905b | ||||||
| Low | 1 (6.7) | 4 (26.7) | 10 (66.7) | 5 (33.3) | 5 (33.3) | 5 (33.3) | ||
| Intermediate | 10 (15.6) | 23 (35.9) | 31 (48.4) | 21 (32.8) | 21 (32.8) | 22 (34.4) | ||
| High | 11 (25.6) | 13 (30.2) | 19 (44.2) | 18 (41.9) | 13 (30.2) | 12 (27.9) | ||
| MRI use | .003a | .049a | ||||||
| No | 17 (18.9) | 22 (24.4) | 51 (56.7) | 28 (31.1) | 28 (31.1) | 34 (37.8) | ||
| Yes | 5 (15.6) | 18 (56.3) | 9 (28.13) | 16 (50) | 11 (34.38) | 5 (15.6) | ||
| PTV volume (cc), | .308a | .204a | ||||||
| mean | 187.8 | 216.8 | 213.4 | 193.8 | 220.5 | 217.5 | ||
| Dose per fraction (Gy) | .322b | .620b | ||||||
| 1.8 | 21 (17.95) | 37 (31.62) | 59 (50.43) | 41 (35.0) | 38 (32.5) | 38 (32.5) | ||
| >1.8 | 1 (20) | 3 (60) | 1 (20) | 3 (60.0) | 1 (20) | 1 (20) | ||
| Localization | .466b | .106b | ||||||
| None | 18 (20.2) | 25 (28.1) | 46 (51.7) | 28 (31.5) | 27 (30.3) | 34 (38.2) | ||
| Gold seeds | 3 (12) | 11 (44) | 11 (44) | 13 (52) | 9 (36) | 3 (12) | ||
| Calypso | 1 (12.5) | 4 (50) | 3 (37.5) | 3 (38) | 3 (38) | 2 (25) | ||
| Prescribed RT dose (Gy), | .119 | .193a | ||||||
| mean | 77.01 | 77.45 | 78.19 | 77.38 | 77.53 | 78.34 | ||
| V40 bladder (%), | .461a | N/A | N/A | N/A | ||||
| mean | 54.84 | 54.23 | 58.87 | |||||
| V65 bladder (%), | .077a | N/A | N/A | N/A | ||||
| mean | 19.01 | 24.07 | 28.28 | |||||
| V70 bladder (%), | .179a | N/A | N/A | N/A | ||||
| mean | 14.83 | 19.85 | 20.18 | |||||
| V75 bladder (%), | .163a | N/A | N/A | N/A | ||||
| mean | 10.94 | 14.11 | 15.77 | |||||
| V40 rectum (%), | N/A | N/A | N/A | .059a | ||||
| mean | 51.0 | 55.17 | 57.62 | |||||
| V65 rectum (%), | N/A | N/A | N/A | .072a | ||||
| mean | 16.34 | 21.08 | 22.59 | |||||
| V70 rectum (%), | N/A | N/A | N/A | .431a | ||||
| mean | 12.7 | 14.75 | 13.9 | |||||
| V75 rectum (%), | N/A | N/A | N/A | .736a | ||||
| mean | 8.31 | 9.23 | 9.03 | |||||
GI, gastrointestinal; GU, genitourinary; IMRT, intensity modulated radiation therapy; MRI, magnetic resonance imaging; N/A, not applicable; PTV, planning target volume; RT, radiation therapy; VMAT, volumetric modulated arc therapy.
a
The P value was calculated by analysis of variance for numeric covariates and the χ2 test for categoric co-covariates.
b
The P value was calculated by the Fisher exact test.