Comprehensive analysis of recurrence patterns and timing in sinonasal malignancies

Sinonasal malignancies tend to recur later than other head and neck cancers do. Due to their rarity and histopathological diversity, large-scale comprehensive studies on sinonasal malignancies remain limited. Therefore, this study aimed to analyze the timing of recurrence in patients with sinonasal malignancies treated in our department, with the goal of informing appropriate post-treatment follow-up strategies. We retrospectively reviewed the timing of disease recurrence in patients with sinonasal malignancies who underwent curative treatment between 2000 and 2021. Recurrence timing was compared by primary site, recurrence site, and histopathological subtype. Recurrence occurred in 59 of 158 patients (37%). The time to recurrence ranged from 2–89 months, with a median of nine months. Overall, recurrence occurred within two years for 78% of cases. In four cases (7%), late recurrence occurred after five years, all of which involved non-squamous cell carcinoma (SCC). No significant differences in recurrence timing were found based on the primary or recurrence site. While no statistically significant difference was observed between SCC and non-SCC, late recurrences beyond two years were more frequently observed in the latter. Most cases of recurrence occurred within two years, suggesting an earlier recurrence than what had previously been reported. However, late recurrences beyond five years also occurred, particularly in non-SCC. Intensive follow-up is essential in the first 2–3 years after treatment, and long-term surveillance tailored to histological subtypes, especially for non-SCC, is necessary.