2776 - Dose-Dependent Occurrence of Nasolacrimal Duct Obstruction and Eye Watering after Radiation Therapy for Nasal/Paranasal Malignant Tumors
Presenter(s)
H. Kawaguchi1, T. Ishihara1, D. Miyawaki1, Y. Horichi2, M. Yui2, T. Furukawa2, H. Shinomiya2, T. Koyama3, N. Kiyota3, K. I. Nibu2, and R. Sasaki1; 1Division of Radiation Oncology, Kobe University Graduate School of Medicine, Kobe, Japan, 2Department of Otolaryngology-Head and Neck Surgery, Kobe University Hospital, Kobe, Japan, 3Department of Medical Oncology/Hematology, Kobe University Hospital, Kobe, Japan
Purpose/Objective(s): Eye watering owing to nasolacrimal duct obstruction is a known side effect following radiation therapy for nasal cavity malignancies. However, the relationship between radiation dose and nasolacrimal duct obstruction remains poorly explored. We hypothesized that the radiation dose is associated with nasolacrimal duct obstruction. This study aimed to investigate this potential dose-dependent effect in a retrospective study.
Materials/Methods: A total of 75 patients who received radiation therapy to the nasal cavity between April 2015 and March 2024 at our hospital were included in this study. The cohort consisted of 47 males and 28 females, with a median follow-up period of 28 months. Diagnoses included malignant melanoma (20 patients), nasal cavity cancer (18 patients), olfactory neuroblastoma (15 patients), malignant lymphoma (13 patients), and others (9 patients). Radiation therapy was administered for curative, postoperative, or palliative purposes. Exclusion criteria included a follow-up period of less than three months, nasolacrimal duct not included in the irradiated field, and cases of re-irradiation. A final cohort of 56 patients was analyzed, including 35 (62.5 %) postoperative cases. Biologically equivalent doses were calculated with an a/ß of 3 (BED3). The Kaplan-Meier method was employed to estimate the incidence of eye watering compared to the log-rank test and fine-gray models.
Results: Among patients who received a Dmax =100 Gy (BED3) to the nasolacrimal duct, 42,3% developed Grade 1 or higher eye watering (11 cases out of 26). In contrast, 22.2% (2 of 9) of patients receiving 80–100 Gy and 4.8% (1 of 21) of patients receiving <80 Gy developed eye watering, suggesting a significant dose-dependent trend (p=0.034). No significant association was observed between surgery status and the incidence of eye watering (p=0.207). Multivariate analysis identified a radiation dose of =100 Gy as a significant factor associated with eye watering (p=0.027). Symptoms of eye watering typically emerged at a median of 3.5 months post-radiation therapy.
Conclusion: The incidence of eye watering due to nasolacrimal duct obstruction is dose-dependent, particularly in patients receiving > 100 Gy (BED3). Furthermore, as the onset of symptoms typically occurs early after radiation therapy, nasolacrimal duct obstruction significantly affects the post-treatment quality of life. These findings underscore the need for clinical studies that might help to establish appropriate dose constraints for the nasolacrimal duct in radiation therapy.