[Retrospective analysis of endoscopic surgery in 60 cases of sinonasal squamous cell carcinoma]

Objective: To analyze the efficacy of endoscopic nasal surgery for sinonasal squamous cell carcinoma (SNSCC) with orbital invasion, the factors affecting the prognosis of patients, and the treatment strategies for preserving the eyeball. Methods: This was a retrospective cohort study, including 60 cases of SNSCC with orbital invasion treated in the Department of Otolaryngology-Head and Neck Surgery, the Second Affiliated Hospital of Harbin Medical University from October 2009 to October 2019. The cohort comprised 39 males and 21 females, aged 33-72 years. Orbital invasion was graded: Grade Ⅰ (destruction of the orbital bone wall), Grade Ⅱ (involvement of the periorbita/orbital fascia, extraconal fat, or medial lacrimal sac), and Grade Ⅲ (involvement of extraocular muscles, eyeball, orbital apex, or optic nerve). All cases underwent multi-disciplinary treatment (MDT), including otolaryngology, ophthalmology and oncology radiotherapy departments, and endoscopic nasal surgery. Survival curves were calculated by Kaplan-Meier method, Log-rank test and Cox risk model were used for univariate and multivariate analysis, respectively. Results: Primary tumor sites were maxillary sinus in 19 cases (31.7%, including 6 cases of pterygopalatine fossa), ethmoid sinus in 25 cases (41.7%, 5 cases with skull base bone involvement but not dura mater), nasal cavity in 11 cases (18.3%), frontal sinus in 3 cases (5.0%), and sphenoid sinus in 2 cases (3.3%). Clinical stages included stage Ⅲ in 53 (88.3%) and stage Ⅳ in 7 (11.7%). The surgical methods of orbital invasion cases were as follows: 18 cases (30.0%) of grade I underwent orbital bone wall resection with orbital fascia and orbital contents preserved; 36 cases (60.0%) in Grade Ⅱ were resected the involved orbital fascia, extra-cone fat and lacrimal sac and preserved the internal cone structure of extra-ocular muscle. Six cases (10.0%) were grade Ⅲ, of which 2 cases were subjected to selective extraocular muscle resection with preserving eyeballs, and 4 cases were subjected to orbital contents removal. The 3-year and 5-year overall survival (OS) rates of all patients were 76.7% and 63.3%, respectively, and the 5-year survival rate of the local recurrence-free group was significantly higher than that of the recurrence group (69.4% vs. 36.4%, χ²=3.91, P=0.048). The 5-year survival rates were significantly negatively correlated with the degrees of orbital invasions (83.3% for grade Ⅰ, 58.3% for grade Ⅱ and 33.3% for grade Ⅲ, (χ²=10.49, P=0.005). The effects of T stages (66.7% in stage T3 vs. 33.3% in stage T4, χ²=7.21, P=0.007) and clinical stages (67.9% in stage III vs. 28.6% in stage IV, χ²=11.80, P=0.001) on survival rates were statistically significant. The 5-year survival rate of patients with cervical lymph node metastases was significantly lower than that of patients without metastasis (37.5% vs. 67.3%, χ²=8.32, P=0.004). The tumor-free survival rate was 56.7%. Cox multivariate analysis identified T stage [HR=3.53 (95%CI: 1.31-9.52)] and clinical stage [HR=35.14 (95%CI: 1.88-658.62)] as independent prognostic factors (both P<0.05). Conclusions: The outcomes of patients with orbital invasion in SNSCC are associated with T stage and clinical stage. If the muscle cone and the structures within the muscle cone are not invaded, eye-preserving surgery is feasible.