Table 4.
Risk factor analysis of developing grade ≥3 late toxicities
| Characteristics |
Grade≥3 late toxicities |
||
|---|---|---|---|
| No (n=17) | Yes (n=9) | p | |
| Age |
|
|
0.218* |
| <55 |
6 (35.3) |
6 (66.7) |
|
| ≥55 |
11 (64.7) |
3 (33.3) |
|
| Gender |
|
|
1.000* |
| Male |
13 (76.5) |
7 (77.8) |
|
| Female |
4 (23.5) |
2 (22.2) |
|
| Surgery |
|
|
0.683* |
| No |
9 (52.9) |
6 (66.7) |
|
| Yes |
8 (47.1) |
3 (33.3) |
|
| Response |
|
|
1.000* |
| CR |
13 (76.5) |
8 (88.9) |
|
| PR |
4 (23.5) |
1 (11.1) |
|
| Histology |
|
|
0.692* |
| NPC |
6 (35.3) |
4 (44.4) |
|
| Non-NPC |
11 (64.7) |
5 (55.6) |
|
| EBRT dose (Gy) |
|
|
0.525† |
| Median (range) |
50.4 (39.6-60) |
55.8 (45-70.2) |
|
| SBRT BED10 (Gy) |
|
|
0.312† |
| Median (range) |
35.7 (13.2-38.4) |
35.7 (28-43.2) |
|
| Total BED10 (Gy) |
|
|
0.287† |
| Median (range) |
93.8 (72.7-107.6) |
96.3 (87.5-118.5) |
|
| SBRT GTV (cc) |
|
|
0.038† |
| Median (range) |
21 (6.9-69.4) |
47.7 (20.9-66.8) |
|
| SBRT fraction number |
|
|
0.339† |
| Median (range) |
5 (3-5) |
3 (2-5) |
|
| SBRT fractional dose (Gy) |
|
|
0.058† |
| Median (range) | 5 (3-7) | 7 (4-8) | |
*Fisher’s exact test; †Mann-Whitney U test
CR, complete response; PR, partial response; NPC, nasopharyngeal carcinoma; EBRT, external beam radiotherapy; SBRT, stereotactic body radiotherapy; BED10, biologically equivalent dose in α/β ratio of 10; GTV, gross tumor volume.