Risk factors and timing of subsequent cutaneous squamous cell carcinoma in patients with cutaneous squamous cell...

Information about the frequency and timing of subsequent cutaneous squamous cell carcinoma (cSCC), along with associated risk factors, is limited. However, this information is crucial to guide follow-up care for these patients.

To evaluate the risk and timing of subsequent cSCC in patients who presented with an initial diagnosis of cSCC.

Retrospective review of an institutional review board-approved, single-institution registry of invasive cSCC. All patients had at least 2 primary cSCCs diagnosed on 2 separate dates 2 months apart.

A total of 299 primary cSCCs were included. At 6 months from initial cSCC diagnosis, 18.06% (n = 54) of patients developed subsequent cSCC; at 1 year, 31.77% (n = 94); at 3 years, 67.56% (n = 202); and at 5 years, 87.96% (n = 263) developed subsequent cSCC. Risk factors associated with subsequent cSCC include age at initial diagnosis (hazard ratio [HR], 1.02; 95% confidence interval, 1.004-1.027; P = .008), T2 stage (HR, 1.66; 95% CI, 1.07-2.57; P = .025), and poor tumor grade. Tumor grades well, moderate, and unknown have HRs of 0.21 (P < .001), 0.16 (P .001), and 0.25 (P = .001), respectively.

Of patients who develop subsequent cSCC, 18.06% do so within 6 months, and 31.77% do so within 1 year of initial cSCC diagnosis. Patients with advanced age, poor histologic differentiation, and American Joint Committee on Cancer T2 stage are at highest risk. Close clinical follow-up after the initial diagnosis is recommended.