Table 3.
Comparison of mean dose to organs at risk by radiation modality when IMRT or proton therapy was used for treatment of the cervical lymph nodes
| Node negative | Node positive | |||||
|---|---|---|---|---|---|---|
| Organ at risk | IMRT (n = 10) | Proton (n = 10) | P | IMRT (n = 16) | Proton (n = 4) | P |
| Oral cavity | 31.5 | 5.1 | <0.001 | 44.6 | 8.5 | <0.001 |
| Larynx | 40.4 | 16.8 | <0.001 | 44.5 | 21.4 | 0.002 |
| Esophagus | 28.7 | 5.9 | <0.001 | 36.0 | 12.1 | <0.001 |
| Better spared parotid | 27.5 | 15.4 | <0.001 | 33.8 | 17.4 | 0.001 |
| Lesser spared parotid | 29.5 (n = 9) | 19.0 (n = 10) | 0.006 | 35.5 (n = 6) | 18.4 (n = 1) | N/A |
IMRT intensity modulated radiation therapy, Radiation dose expressed in Gy for IMRT and Gy (RBE) for proton therapy