Bone Metastasis is Uncommon in Patients with Oral Squamous Cell Carcinoma at Diagnosis-Bone Scan may be Not Necessary for Staging

Only a small portion of the patients with oral squamous cell carcinoma (OSCC) experience bone metastasis. This study is to evaluate the percentage of bone metastasis at diagnosis and after treatment and to discuss whether bone scan is necessary in OSCC patients. The medical records of all patients with newly diagnosed OSCC receiving bone scan or positron emission tomography (PET) at diagnosis between 2010 and 2015 were retrospectively reviewed. A total of 1049 patients were enrolled, including 458 (44%) with early stage tumor and 591 (56%) with late stage tumor. In total, 33 (3.1%) patients had bone metastasis at diagnosis (9 patients, 0.86%) and after treatment (24 patients, 2.29%) during the mean follow-up of 12 months. Among those with subsequent bone metastasis, only 5 (21%) patients had bone-only metastasis. All patients with bone metastasis before primary treatment and all but two patients with bone metastasis after treatment had locoregionally advanced OSCC. The mean survival time of the 33 patients after diagnosis of bone metastasis was 121 days. Bone metastasis is uncommon in patients with OSCC. It is not necessary to routinely use bone scan for initial staging, especially early stage OSCC, and for follow-up.