Table 4 Risk factor analysis of developing grade ≥3 late toxicities

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)