Head and Neck Osteosarcoma : Perineural Invasion is Associated With Disease-Free Survival and Tumor Metastasis

Background: Head and neck osteosarcoma (HNOS) is the most common bone malignancy in the head and neck region, accounting for 10% of all osteosarcoma cases. Perineural invasion (PNI) is a notable indication of aggressive tumor behavior, which includes the phenomenon of tumor cells invading any of the 3 layers of the nerve sheath or tumor cells gathering, encircling one-third of the nerve circumference, and infiltrating and metastasizing along the nerve. PNI has been reported in various malignant tumors and is considered to be linked to poor prognosis. Purpose: The study's purpose is to measure the association between PNI and survival outcomes in patients with HNOS. Study Design, Setting, Sample: This retrospective cohort study focused on HNOS patients who underwent surgery at the Department of Oral and Maxillofacial Head and Neck Oncology, Shanghai Ninth People's Hospital School of Medicine, Shanghai Jiao Tong University, from January 1, 2019 to December 31, 2021. Patients who did not undergo complete surgical resection of the tumor, did not receive a conventional osteosarcoma diagnosis, and had positive surgical margins were eliminated. Predictor Variable: The predictor variable is PNI status. The pathological section of the tumor was consistent with any of the PNI features, which was considered PNI-positive. Main Outcome Variable(s): The primary outcome variables were 3-year disease-free survival (DFS) and 3-year overall survival. Secondary outcomes were 3-year tumor local recurrence and 3-year metastasis (MT). Covariates: Covariates were categorized into the following categories: demographic variables (age, sex), clinical variables (tumor region, primary tumor), and treatment variables (chemotherapy, radiotherapy).