Rural patients with oral squamous cell carcinoma experience better prognosis and long-term survival.

OBJECTIVES: No studies have attempted to examine the role of geographic location on oral squamous cell carcinoma (OSCC) disease progression in the United States (US). The purpose of this study is to analyze rural-urban differences in prognosis and long-term survival in patients with OSCC. MATERIALS AND METHODS: This retrospective cohort study utilizes the National Cancer Institute's (NCI) Surveillance, Epidemiology and End Results (SEER) database to examine primary OSCC diagnoses from 1990 to 2015 in the US. The primary predictor variable was patient Rural-Urban Continuum Code (RUCC) (rural vs. urban). The primary outcome variable consisted of overall survival time after initial diagnosis. Additional variables assessed include patient demographics, primary anatomical site of the cancer, histological diagnosis, stage/grade at time of diagnosis, and disease outcome. Descriptive statistics were calculated, and categorical variables were compared. Additional cumulative survival and univariate/multivariate analyses were performed. RESULTS: 46,678 cases of OSCC between 1990 and 2015 were identified. The rural subgroup was more likely to present at the time of diagnosis with a lower grade (p < 0.001) and an earlier stage (p < 0.001). Rural populations demonstrated superior overall survival (p < 0.001), whereas urban populations were more likely to die as a result of their OSCC (p < 0.001). After adjusting for all patient-specific factors, urban status still yielded a poorer disease prognosis. CONCLUSION: Living in rural areas is associated with better prognosis and long-term survival in patients with OSCC. Further studies are needed to better elucidate the mechanisms underlying these findings.

Biallelic PTCH1 Inactivation Is a Dominant Genomic Change in Sporadic Keratocystic Odontogenic Tumors.

Keratocystic odontogenic tumors (KCOTs) are locally aggressive odontogenic neoplasms with recurrence rates of up to 60%. Approximately 5% of KCOTs are associated with nevoid basal cell carcinoma (Gorlin) syndrome and 90% of these show genomic inactivation of the PTCH1 gene encoding Patched 1. Sporadic KCOTs reportedly have PTCH1 mutations in 30% of cases, but previous genomic analyses have been limited by low tumor DNA yield. The aim of this study was to identify recurrent genomic aberrations in sporadic KCOTs using a next-generation sequencing panel with complete exonic coverage of sonic hedgehog (SHH) pathway members PTCH1, SMO, SUFU, GLI1, and GLI2. Included were 44 sporadic KCOTs from 23 female and 21 male patients with a median age of 50 years (range, 10 to 82 y) and located in the mandible (N=33) or maxilla (N=11). Sequencing identified PTCH1 inactivating mutations in 41/44 (93%) cases, with biallelic inactivation in 35 (80%) cases; 9q copy neutral loss of heterozygosity targeting the PTCH1 locus was identified in 15 (34%) cases. No genomic aberrations were identified in other sequenced SHH pathway members. In summary, we demonstrate PTCH1 inactivating mutations in 93% of sporadic KCOTs, indicating that SHH pathway alterations are a near-universal event in these benign but locally aggressive neoplasms. The high frequency of complete PTCH1 loss of function may provide a rational target for SHH pathway inhibitors to be explored in future studies.

Mucocutaneous Diseases.

Mucocutaneous diseases affecting the oral cavity are predominantly immune mediated or inflammatory. Three of the most common and clinically significant conditions are reviewed in this article: lichen planus, pemphigus vulgaris, and mucous membrane pemphigoid. Because oral manifestations may be the first or only manifestation of mucocutaneous diseases, oral health professionals play a critical role in the early diagnosis and multidisciplinary management of these conditions.