Inverted Papilloma: Prognostic Factors with Implications for Resection Margins

Background: Inverted papilloma (IP) of the sinonasal tract remains a surgical disease that requires complete extirpation because of high recurrence rates and significant potential for malignant transformation. Many methods of excision are used, ranging from endoscopic techniques to external-transfacial techniques, with similar recurrence rates regardless of surgical approach. Among these techniques, the impact of using surgical margins for confirmation of total resection is not standardized as its benefit is unproved. We aim to review our institution’s experience with treating IP and assess whether obtaining surgical margins reduces the rates of recurrence.

Methods: We performed a retrospective chart review of patients with IP treated at the University of Michigan from 1996-2011. Patients with IP, regardless of the presence of dysplasia or carcinoma, were included only if primary surgical resection with curative intent was performed.

Results: We studied 129 patients, including 105 IPs, 5 IPs with dysplasia, and 19 IPs with carcinoma. The mean overall survival was 182.8 months, and the mean disease-specific survival was 199.3 months. The median local-regional control rate was 95.6 months. Tumor control rates at 2, 3, and 5 years were 79.7%, 77.9%, and 61%, respectively. Margins were obtained for 64 patients (all negative margins), and this group demonstrated no difference in tumor control compared with patients who did not have additional surgical margins. Smoking status significantly affected overall survival (P = 0.013) but did not influence disease survival or local regional control. Similarly, the anatomic site of origin did not affect any outcome measure. Primary resection and surgery for recurrent disease showed no difference in recurrence rates. The 5-year disease-specific survival for IP, IP with dysplasia, and IP with carcinoma were 98.6%, 100%, and 66%, respectively (P < 0.000). The local-regional control rates for IP, IP with dysplasia, and IP with carcinoma were 78%, 100%, 77%, respectively at 2 years and 60%, 100%, 65%, respectively at 5 years (NS). Krouse stage 4 patients experienced shorter overall survival and disease-specific survival (P < 0.000) but had similar recurrence rates.

Conclusion: In surgery for IP, additional tissue for surgical margins does not appear to affect tumor control rates. Patients with carcinoma or stage 4 disease demonstrate decreased survival, but recurrence rates are high in all groups. No clear predictors of malignancy were seen in this study, which highlights the need for further research to predict this phenomenon.