Contents lists available at ScienceDirect Oral Oncology journal homepage: www.elsevier.com/locate/oraloncology Treatment outcomes of squamous cell carcinoma of the oral cavity in young adults ☆ Mauricio E. Gamez a,1 , Ryan Kraus c,1 , Michael L. Hinni b , Eric J. Moore d , Daniel J. Ma e , Stephen J. Ko f , Jean Claude M. Rwigema a , Lisa A. McGee a , Michele Y. Halyard a , Matthew R. Buras g , Robert L. Foote e , Samir H. Patel a, ⁎ a Department of Radiation Oncology, Mayo Clinic Hospital, Phoenix, AZ, United States b Department of Otolaryngology-Head and Neck Surgery/Audiology, Mayo Clinic Hospital, Phoenix, AZ, United States c University of Southern California Keck School of Medicine, Los Angeles, CA, United States d Department of Otorhinolaryngology-Head and Neck Surgery, Mayo Clinic, Rochester, MN, United States e Department of Radiation Oncology, Mayo Clinic, Rochester, MN, United States f Department of Radiation Oncology, Mayo Clinic, Jacksonville, FL, United States g Biostatistics, Mayo Clinic, Scottsdale, AZ, United States ARTICLE INFO Keywords: Head and neck cancer Oral cavity Oral tongue ABSTRACT Objectives: The natural history of squamous cell carcinoma (SCC) of the oral cavity (OC) in young adults is unknown. We sought to provide an updated report on treatment outcomes of patients with OC SCC who were 40 years or younger. Materials and methods: We performed a retrospective analysis of 124 consecutive patients with primary OC SCC treated at Mayo Clinic (1980–2014). Patient and tumor characteristics and treatment approach were abstracted from patient charts. Results: Median patient age was 35 years (range, 19–40 years). The most common primary site was oral tongue (107 patients; 86.3%). Most patients (101; 81.5%) underwent wide local excision. Surgery alone was curative in 77 patients (62.1%); 47 (37.9%) received radiotherapy, and 26 (21%) received chemotherapy. Five-year overall survival (OS) was 78.1%; 10-year OS was 76.9%. Five-year disease-free survival (DFS) was 66.6%; 5-year local control was 87.6%; and 5-year locoregional control was 78.5%. On multivariable analysis, factors associated with worse OS and DFS were higher pathologic T stage (P = .008), lymph node positivity (P < .001), and disease recurrence (P < .001). Conclusion: Young adults with primary OC SCC may be treated with a similar treatment approach as older adults. Introduction Oral cavity cancer (OCC) includes cancers that involve the lip, floor of the mouth, oral tongue, buccal mucosa, upper and lower gingivae, hard palate, and retromolar trigone, with the oral tongue being the most commonly affected subsite [1,2]. More than 90% of cancers in the oral cavity (OC) are squamous cell carcinomas (SCCs) [3]. In 2018, an estimated 33,950 cases of OCC and 6800 deaths are expected to occur [4]. Historically, OCC has been thought of as a disease of older men who have a history of tobacco and alcohol use; the average age at di- agnosis is 60 years; approximately 95% of OCC occurs after age 45 years [5]. Although the overall incidence of OCC has decreased over the past 30 years in the United States [6,7], the incidence of OCC in younger patients increased over the same period, peaked in the late 1980s, and has remained at an elevated level [2]. Of all patients with OCC, 4% to 6% are younger than 40 years [2,8–10], and most recent studies report https://doi.org/10.1016/j.oraloncology.2018.10.014 Received 30 August 2018; Received in revised form 10 October 2018; Accepted 14 October 2018 Abbreviations: AJCC, American Joint Committee on Cancer; DFS, disease-free survival; EGFR, epidermal growth factor receptor; HR, hazard ratio; LC, local control; LRC, locoregional control; MVA, multivariable analysis; OC, oral cavity; OCC, oral cavity cancer; OS, overall survival; SCC, squamous cell carcinoma; UVA, uni- variable analysis ☆ Portions of this manuscript have been published in abstract form: Int J Radiat Oncol Biol Phys. 2018;100(5):1340–1. ⁎ Corresponding author at: Department of Radiation Oncology, Mayo Clinic Hospital, 5777 E Mayo Blvd, Phoenix, AZ 85054, United States. 1 Both authors equally contributed to this manuscript. E-mail address: patel.samir@mayo.edu (S.H. Patel). Oral Oncology 87 (2018) 43–48 1368-8375/ © 2018 Elsevier Ltd. All rights reserved. T