The aim of this retrospective study was to assess the efficacy and safety of cetuximab therapy for patients with locally advanced (LA) and recurrent/metastatic (R/M) oral squamous cell carcinoma (OSCC), with a specific focus on distant metastases (DMs). Data from 21 patients with unresectable LA and R/M OSCC treated with cetuximab therapy in our department between December, 2012 and July, 2015 were reviewed. The endpoint was the time-to-progression and the assessments made were tumor response rate, progression-free survival (PFS), overall survival (OS) and safety. The overall response rate was 57.1%, with a complete response (CR) rate of 33.3%. The overall median PFS and OS were 5.5 and 8.0 months, respectively. For patients with DMs, the overall response rate was 60.0%, with a CR rate of 40.0%. The median PFS and OS were 3.8 and 5.8 months, respectively. In addition, improved 1-year OS was observed following approval of cetuximab, although the differences between the group of patients treated after that time and historical controls were not statistically significantly (P=0.246). Grade 3–4 adverse events included infusion reaction (4 cases), neutropenia, hypophosphatemia, upper gastrointestinal hemorrhage, liver toxicity and mucositis (1 case each). There was one cetuximab-related death due to interstitial pneumonia. An acne-like rash was observed in all cases, but no grade 3 or 4 rash was reported. Hypomagnesemia was observed in 10 cases. Our results suggest that cetuximab may display significant therapeutic efficacy in patients with unresectable LA and R/M OSCC, including those with DMs.

The aim of the present study was to identify the most useful markers for predicting recurrence of keratocystic odontogenic tumors (KCOTs). A total of 65 tumor samples from 63 patients diagnosed with typical parakeratinized cysts and KCOTs between 1992 and 2014 were retrospectively studied. Clinical and histopathological data and treatment modality were reviewed. In addition, the expression profiles of Ki-67, cluster of differentiation (CD)34 and podoplanin were assessed using immunohistochemistry. The association between these factors and the rate of KCOT recurrence was evaluated. The presence of daughter cysts, epithelial islands and high Ki-67, CD34 and podoplanin expression levels were revealed to be associated with tumor recurrence. In particular, univariate analysis revealed that high CD34 expression levels were significantly associated with tumor recurrence (P=0.034), as was conservative surgical treatment (P=0.003). Multivariate analysis revealed that conservative treatment was the greatest independent risk factor for tumor recurrence (odds ratio=13.337; P=0.018). These results suggest that overexpression of CD34 may be a potent predictor of tumor recurrence and radical treatment of the teeth that are in contact with the tumors is recommended in order to prevent tumor recurrence.

Primary intraosseous squamous cell carcinoma (PIOSCC) is a rare malignant odontogenic tumor that originates from odontogenic epithelial remnants. It is often difficult to diagnose PIOSCC definitively; hence, extraction or surgical treatment is performed before the initial diagnosis in most cases. The present study examined new insights into and prognostic factors of patients with PIOSCC admitted to the authors' department. An extensive record review was conducted of patients who underwent radical surgery for PIOSCC from January 2001 through December 2014. Of all cases of OSCC, the frequency of PIOSCC was 1.45%. The 2-year relapse-free survival (RFS) and overall survival (OS) rates were 50.0 and 41.6% in all cases, respectively. Three patients underwent surgery or tooth extraction before the initial diagnosis; in fact, intervention before initial diagnosis was found to be an important poor prognostic factor for RFS and OS. In contrast, patients who were not treated before the initial diagnosis was made did not exhibit any locoregional recurrence. The treatment of PIOSCC should be similar to that for oral cancer with at least clinical stage T3N0 in the National Comprehensive Cancer Network clinical practice guidelines. In addition, cases of PIOSCC that are not treated before the initial diagnosis are more likely to obtain a good prognosis.