Association Between Immunosuppression and Outcomes in Oral Cavity Squamous Cell Carcinoma

Objective To assess the effect of immunosuppression on recurrence and mortality outcomes in oral cavity squamous cell carcinoma (SCC) after initial surgical treatment. Study Design Retrospective cohort study. Setting A single academic tertiary referral center. Methods Patients with oral cavity SCC treated with initial surgery were included. Immunosuppressed versus nonimmunosuppressed groups were compared. Primary end points were 5-year overall recurrence and all-cause mortality. Secondary end points were recurrence subtypes (local, regional, and distant) and disease-specific mortality. Results Of 803 patients with oral cavity SCC, 71 (9%) were immunosuppressed from therapeutic drug use (n = 48) or systemic disease (n = 23). The immunosuppressed group consisted of patients with a history of transplant (21%), autoimmune or pulmonary disorder (45%), hematologic malignancy or myeloproliferative disorder (30%), and HIV infection (3%). After adjusting for baseline variables of age, sex, comorbidities, pathologic tumor characteristics, and adjuvant treatment, all recurrence and mortality outcomes were worse in the immunosuppressed group. The multivariate-adjusted hazard ratio for overall recurrence was 2.16 (95% CI, 1.50-3.12; P < .01), and all-cause mortality was 1.79 (95% CI, 1.15-2.78; P < .01) in Cox regression analysis. The 2 groups were then matched in a 1:5 ratio according to the same baseline variables. All end points apart from disease-specific mortality were significantly worse in the immunosuppressed group after matching. Conclusion This study demonstrates that immunosuppression is associated with poor outcomes in oral cavity SCC, with an approximate 2-fold increase in rates of recurrence and mortality. Future studies are needed to assess the risks and benefits of adjusting therapeutic immunosuppression in this population.