Identifying risk factors for the prognosis of head and neck cutaneous squamous cell carcinoma: A systematic review and meta-analysis

In this study, we sought to identify the potential impacts of disease characteristics on the prognosis of cutaneous squamous cell carcinoma (cSCC). We searched the PubMed, EmBase, and Cochrane Library databases from their inception until February 2020 to identify studies that investigated the prognosis of cSCC. The pooled effect estimates were applied using odds ratios (OR) and 95% confidence intervals (CI) and were calculated using the random-effects model. Forty-three studies including a total of 21,530 patients and reporting 28,627 cases of cSCC were selected for the final meta-analysis. Poor differentiation (OR, 3.54; 95% CI, 2.30-5.46; P < 0.001), perineural invasion (OR, 3.27; 95% CI, 1.60-6.67; P = 0.001), Breslow greater than 2 mm (OR, 5.47; 95% CI, 2.63-11.37; P < 0.001), diameter greater than 20 mm (OR, 4.62; 95% CI, 2.95-7.23; P < 0.001), and location on temple (OR, 3.20; 95% CI, 1.12-9.15; P = 0.030) were associated with an increased risk of recurrence, whereas immunosuppression status and location on cheek, ear, or lip were not associated with the risk of recurrence. Poor differentiation (OR, 6.82; 95% CI, 4.66-9.99; P < 0.001); perineural invasion (OR, 7.15; 95% CI, 4.73-10.83; P < 0.001); Breslow greater than 2 mm (OR, 6.11; 95% CI, 4.05-9.21; P < 0.001); diameter greater than 20 mm (OR, 5.01; 95% CI, 2.56-9.80; P < 0.001); and location on ear (OR, 2.38; 95% CI, 1.39-4.09; P = 0.002), lip (OR, 2.15; 95% CI, 1.26-3.68; P = 0.005), and temple (OR, 2.77; 95% CI, 1.20-6.40; P = 0.017) were associated with an increased risk of metastasis, whereas immunosuppression status and location on cheek did not affect the risk of metastasis. Finally, poor differentiation (OR, 5.97; 95% CI, 1.82-19.62; P = 0.003), perineural invasion (OR, 6.64; 95% CI, 3.63-12.12; P < 0.001), and Breslow greater than 2 mm (OR, 3.42; 95% CI, 1.76-6.66; P < 0.001) were associated with an increased risk of disease-specific death, whereas diameter; immunosuppression status; and location on ear, lip, and temple did not affect the risk of disease-specific death. We found that differentiation, perineural invasion, depth, diameter, and location could affect the prognosis of cSCC. The potential role of other patient characteristics on the prognosis of cSCC should be identified in further large-scale prospective studies.