Prognostic value of two tumour staging classifications in patients with sinonasal mucosal melanoma.

INTRODUCTION: Sinonasal mucosal melanoma is a rare disease associated with a very poor prognosis. The purpose of this study was to assess the prognostic value of the 2 staging systems published in the literature for these tumours: the American Joint Committee on Cancer (AJCC) Cancer Staging Manual for mucosal melanoma of the head and neck published in 2009 (7th edition) and the AJCC Cancer Staging Manual for cancers of the nasal cavity and paranasal sinuses published in 2002 (6th edition) and the prognostic value of tumour site, either limited to the nasal cavities or with paranasal sinus invasion.

METHODS: A retrospective study was conducted on 18 patients treated between August 1998 and June 2014. Each lesion was staged according to the AJCC Cancer Staging Manual 2002 and 2009 and the following data were collected: age, sex, tumour site, initial symptoms, treatment modalities, follow-up, recurrences and overall survival. Patient survival, from the date of discovery of the melanoma until death, was analysed by Kaplan-Meier survival curves and between-group comparison of survival was performed with a log rank test.

RESULTS: The mean age at diagnosis was 72 years (range: 54-94) and the cohort comprised 11 women and 7 men. The median overall survival was 80 months, the 1-year overall survival was 82.6% and the 5-year overall survival was 54.5%. The AJCC 2002 staging system presented a statistically significant prognostic value (P=0.0476), while no statistically significant prognostic value was observed for the AJCC 2009 staging system (P=0.108). Paranasal sinus invasion was significantly associated with a poor prognosis (P=0.0039).

CONCLUSION: This study demonstrates the superiority of the non-specific AJCC 2002 Cancer Staging Manual. Medical and surgical management must take paranasal sinus invasion into account, as it constitutes a major prognostic factor.