Hypothyroidism following immunotherapy predicts more postoperative complication in oral squamous cell carcinoma.

Objective: To evaluate the impact of hypothyroidism that develops following immunotherapy on surgical outcomes in patients diagnosed with oral cancer.

Methods: Patients with surgically treated oral cancer following neoadjuvant immunochemotherapy were retrospectively enrolled. Impact of hypothyroidism on postoperative complication were analyzed.

Results: In total, 303 patients were enrolled. In comparison to patients with normal thyroid function, patients with subclinical or overt hypothyroidism did not exhibit a significantly increased risk of surgical site infection, but both conditions were associated with a higher risk of fistula formation and wound debridement. The cohort suffering from subclinical hypothyroidism exhibited odds ratios (ORs) of 1.88 [95% confidence interval (CI): 1.12-5.47] for fistula development and 1.95 [95% CI: 1.27-6.98] for wound debridement. Patients with overt hypothyroidism had a 2.03-fold higher risk of fistula formation (95% CI: 1.35-6.24) and a 2.17-fold higher risk of wound debridement (95% CI: 1.20-7.53). The rate of wound debridement escalated to 40.0% when both hypothyroidism and diabetes were present simultaneously; in contrast, it diminished to 20.0% in cases of isolated hypothyroidism, 12.1% in individuals with diabetes alone, and a mere 5.2% in patients devoid of both conditions. The incidence of fistula formation was most pronounced in patients with coexisting diabetes and hypothyroidism, followed closely by 6.7% in those with solely hypothyroidism. The occurrence of fistulas was remarkably rare among patients with only diabetes or those lacking both factors.

Conclusions: Hypothyroidism induced by neoadjuvant immunotherapy exerts a considerable negative impact on the formation of fistulas and wound debridement in patients with locally advanced oral cancer, an effect that may be exacerbated by the presence of diabetes.