Anterior Segment Complications After Radiotherapy for Sinonasal and Nasopharyngeal Cancer: High Frequency in Maxillary Sinus Cancer Treated with RADPLAT

Objectives: To characterize the frequency and temporal patterns of anterior segment findings after radiotherapy for sinonasal and nasopharyngeal cancer, with particular focus on anterior segment neovascularization and its association with superselective intra-arterial cisplatin infusion with concurrent radiotherapy (RADPLAT). Methods: We retrospectively reviewed 113 patients treated with intensity-modulated radiotherapy between 2019 and 2022. Anterior segment findings were evaluated using the whole cohort as the denominator and among patients referred for ocular symptoms. Cumulative incidence was estimated with death as a competing risk using the Aalen–Johansen estimator and compared using Gray’s test. Results: Median follow-up was 1666 days. Forty-seven patients (41.6%) were referred to ophthalmology. Anterior segment findings occurred in 16/60 patients (26.7%) with nasal cavity cancer and 13/31 (41.9%) with maxillary sinus cancer (p = 0.16); 5-year cumulative incidences were 27.7% and 46.1%, respectively (p = 0.018). Anterior segment neovascularization occurred in 7/113 patients (6.2%), including 6/21 (28.6%) treated with RADPLAT and 1/92 (1.1%) without RADPLAT (p < 0.001); 5-year cumulative incidences were 31.4% and 1.4%, respectively (p < 0.001). Among patients with maxillary sinus cancer, neovascularization occurred in 5/19 RADPLAT-treated patients and 0/12 non-RADPLAT patients (p = 0.13); however, median follow-up was substantially shorter in the non-RADPLAT group (385 vs. 1784 days). Neovascularization developed late (median, 975 days), and four affected patients had final best-corrected visual acuity below 0.05. Conclusions: Anterior segment findings showed distinct temporal patterns after radiotherapy. Late, vision-threatening neovascularization was strongly associated with RADPLAT, although causality cannot be established because treatment selection was confounded by tumor site, disease extent, orbital invasion, and radiotherapy characteristics. These findings identify anterior segment neovascularization as an important safety signal warranting prospective evaluation. Standardized baseline ophthalmological assessment, long-term surveillance, and patient-level ocular dosimetry are needed to clarify mechanisms and define appropriate follow-up strategies.