ESTRO 2024 - Abstract Book

S1369

Clinical - Head & neck

ESTRO 2024

Other

30 (7.6%)

58 (7.0%)

0.817

T

stage:

190 (47.9%) / 205 (51.6%)

433 (52.3%) / 395 (47.7%) 217 (26.2%) / 609 (73.6%)

2 (0.2%)

0.190

T0/T1/T2 vs. T3/4

N

stage:

88 (22.2%) / 307 (77.3%)

4 (0.3%)

0.159

N0 vs. N1/N2/N3

Smoking:

2 (0.2%)

Current

169 (42.6%)

256 (30.9%)

<0.001

Former

137 (34.5%)

316 (38.2%)

0.239

Never

91 (22.9%)

254 (30.7%)

0.006

Extractions pre-RT

11 (0.9%)

205 (51.6%)

353 (42.6%)

0.014

Pre-RT

surgery:

117 (29.5%) / 280 (70.5%) 304 (76.6%) / 93 (23.4%) 213 (53.7%) / 184 (46.3%)

235 (28.4%) / 593 (71.6%) 624 (75.3%) / 204 (24.6%) 421 (50.8%) / 407 (49.2%)

0 (0.0%)

0.744

PORT vs. Primary RT

RT

technique:

0 (0.0%)

0.695

IMRT vs. VMAT

Fraction

size:

0 (0.0%)

0.390

>2Gy vs. <=2Gy

Mandible

volume

(cc) mean (range)

4 (0.3%)

77.0 (28.7-154.5)

74.3 (18.8-170.5)

0.025

Chemotherapy

20 (1.6%)

279 (70.3%)

528 (63.7%)

0.059

Results:

The average mean and maximum doses across the entire cohort were higher in the ORN group (Dmeanavg = 43.6 Gy, Dmaxavg = 69.9 Gy) than in the control group (Dmeanavg = 40.6 Gy. Dmaxavg = 68.5 Gy) (Figure 1). At multivariable analysis, the following clinical and dosimetric variables were selected by the SFLR model: pre-RT dental extractions (OR 1.45 CI 1.13-1.87), smoking during RT (OR 1.78 CI 1.36-2.33), follow-up time (OR 2.55 CI 1.27-5.11), mandible volume (OR 3.46 CI 1.44-8.32) and D30% (OR 1.06 CI 1.04-1.07).