Prediction of Maxillary Bone Invasion in Hard Palate/Upper Alveolus Cancer: A Multi-Center Retrospective Study

SIMPLE SUMMARY: Pathological bone invasion is an independent, poor prognostic factor in oral cancer, and accurate prediction of bone invasion is critical to the prognosis estimation and treatment decision. Many previous studies on bone invasion of oral cancer have focused on mandibular invasion, but there have been relatively few reports about the maxillary bone invasion (MBI) of hard palate/upper alveolus (HP/UA) cancer. Therefore, we have attempted to design a prediction model for MBI using several radiological and clinical variables of HP/UA cancer. We found that computerized tomography (CT) alone predicted MBI, with a discrimination ability of 77.9%. Meanwhile, the discrimination performance was increased up to 91.1% in a prediction model including CT findings, tumor dimensions, clinical factors (male sex, nodal metastasis), and maximal standardized uptake value of positron emission tomography/CT. In addition, the scoring system using these variables clearly distinguished low-, intermediate-, and high-risk groups for MBI in HP/UA cancer. ABSTRACT: Background: maxillary bone invasion (MBI) is not uncommon in hard palate or upper alveolus (HP/UA) cancer; however, there have been relatively few reports about the MBI of HP/UA cancer. Patients and Methods: this was a multi-center retrospective study, enrolling 144 cases of HP/UA cancer. MBI was defined by surgical pathology or radiology follow-up. The multiple prediction models for MBI were developed in total cases and in cases having primary bone resection, using clinical and radiological variables. Results: computerized tomography (CT) alone predicted MBI, with an area under receiver operating curve (AUC) of 0.779 (95% confidence interval (CI) = 0.712–0.847). The AUC was increased in a model that combined tumor dimensions and clinical factors (male sex and nodal metastasis) (0.854 (95%CI = 0.790–0.918)). In patients who underwent (18)fluorodeoxyglucose positron emission tomography/CT (PET/CT), the discrimination performance of a model including the maximal standardized uptake value (SUVmax) had an AUC of 0.911 (95%CI = 0.847–0.975). The scoring system using CT finding, tumor dimension, and clinical factors, with/without PET/CT SUVmax clearly distinguished low-, intermediate-, and high-risk groups for MBI. Conclusion: using information from CT, tumor dimension, clinical factors, and the SUVmax value, the MBI of HP/UA cancer can be predicted with a relatively high discrimination performance.