Tubarial gland sparing with intensity modulated radiation therapy for oropharyngeal cancers: A pilot study of dosimetric feasibility.

BACKGROUND

Tubarial glands are a new organ at risk for head and neck cancer radiation therapy (RT). We aimed to study the feasibility of sparing them using intensity-modulated radiation therapy (IMRT).

METHODS

Tubarial glands were delineated for 17 patients with oropharyngeal carcinoma receiving definitive RT, and treatment plans were re-optimized to spare dose to the tubarial glands while maintaining target coverage. A paired t test was performed to compare the mean dose of tubarial glands and target coverage.

RESULTS

The difference in mean doses was 4.9 and 7.0 Gy for the ipsilateral and contralateral tubarial glands, respectively (p < 0.01). The mean dose to tubarial gland was ≤39 Gy in 35% versus 47% (ipsilateral) and 70% versus 100% (contralateral) in clinical and re-optimized plans, respectively. Re-optimized ipsilateral tubarial gland mean ≤39 Gy was achieved more commonly in patients with base of tongue versus tonsil primaries (86% vs. 20%, p = 0.02).

CONCLUSION

This pilot study demonstrates the dosimetric feasibility of tubarial gland sparing with IMRT. Dosimetric constraints need to be determined with larger studies.