Risk factors and prognosis for the primary intraosseous carcinoma of the jaw

Primary intraosseous carcinoma (PIOC) is a rare but aggressive type of odontogenic tumour arising within the jawbone. Diagnosis criteria and treatment strategy remain difficult and controversial. The present study aimed to clarify the clinicopathological features and determine prognostic factors in management of PIOC. A retrospective study of 30 patients with PIOC, treated at the Hospital of Stomatology of Sun Yat-sen University between 2009 and 2017, was conducted. Clinical, histopathological and treatment modality data were collected. Follow-up data were recorded to determine prognostic factors. There were 19 males and 11 females with a mean age of 52.3 years. The most common location of the tumour was the mandible (90%). Having a history of tooth extraction or tooth mobility was the major characteristic symptom (63.3%), jaw swelling coming in second (53.3%). Half of the patients underwent surgery alone. The estimated 2-year overall survival rate (OS) and recurrence-free survival rate (RFS) were 61.3% and 40.1%, respectively. Higher histological grade was an independent risk factor for poor OS (hazard ratio (HR) 0.233 [0.059-0.915], P=0.037), while at pN₊ stage for RFS, HR=5.627 [1.199-26.409], P=0.029. Because of its rarity and intrabony site, the classification, staging and treatment guidelines for PIOC should be further studied and established.