Author(s)
Connie J Zhou, BS (1)
Neil N Patel, MD (2)
Ivan H El-Sayed, MD (2)
Jonathan R George, MD (2)
Chase M Heaton, MD (2)
William R Ryan, MD (2)
Patrick K Ha, MD (2)
Affiliation(s)
(1)University of California, School of Medicine; (2) University of California San Francisco, Department of Otolaryngology-Head and Neck Surgery;
Abstract:
Introduction:
Studies have demonstrated an increasing incidence of young patients with OCSCC. Moreover, large case series have suggested that a younger phenotype of OCSCC exhibits clinical differences when compared to older patients and differences in survivorship has been noted based on subsite irrespective of age. However, differences in the incidence and survival by anatomical subsite, stratified by age have not been studied on a national level. This study aims to evaluate differences in the incidence and survival by subsite in young (<50 years old) and old (50+ years old) oral cavity squamous cell carcinoma (OCSCC) patients.
Methods
Utilizing the Surveillance, Epidemiology, and End Results (SEER) Program Research Plus Data, 18 Registries November 2020 Submission data between 2000 and 2018, patient demographics, clinicopathological features, and outcomes were recorded. Cox regression for survival analyses were performed to compare survival and incidence rates of OCSCC in 7 subsites (lip, oral tongue, buccal mucosa, alveolus, retromolar trigone, hard palate, and floor of mouth) stratified by age. Covariates in the analysis included stage and sex. Cause-specific mortality was the primary outcome.
Results
The study included 16,104 individuals, with 2,458 and 13,646 in the young and old groups, respectively. 35.8% were female (as defined in SEER) in the young group and 39.7% in the old group. Mean length of follow up was 57.4 months (SD = 46.6). The older cohort demonstrated higher heterogeneity by SCC subsite compared to the young cohort. By AJCC6 staging, 39.2% and 35.3% of patients in the young and old groups, respectively, presented with Stage I OCSCC.
For young patients, mortality from buccal mucosa SCC was higher (Hazard Ratio (HR): 1.331, p = 0.022), but was lower in lip SCC (HR: 0.365, p = 0.026) when compared to oral tongue SCC. Young patients with hard palate SCC demonstrated a trend towards lower mortality (HR: 0.583) compared to oral tongue (p = 0.067). For old patients, SCC of buccal mucosa (HR: 1.307, p < 0.001), floor of mouth (HR: 1.115, p = 0.003), hard palate (HR: 1.216, p = 0.006), and lip (HR: 0.462, p < 0.001) demonstrated significantly different overall survival relative to oral tongue.
Conclusion
This study is consistent with previous studies demonstrating oral tongue is the most common subsite among young patients. In both cohorts, buccal mucosa SCC confers the highest mortality risk. While in older patients, hard palate SCC is associated with higher mortality, this trend does not translate to the young patient cohort. Further studies are needed to elucidate why such differences are present between older and younger patients. However, this study demonstrates that a more accurate prognosis could be obtained when accounting for age and subsite of oral cavity SCC.