Incidence of cancer among patients with hidradenitis suppurativa

Background: On the basis of some case reports, a relationship has been sugg ested between hidradenitis suppurativa (HS) and the development of nonmelan oma skin cancer. Objectives: To confirm this relationship and to explore the risk of other c ancers among patients with HS. Patients: Patients with a discharge diagnosis of HS were obtained from the computerized database of hospital discharge diagnoses from January 1, 1965, through December 31, 1997. A total of 2119 patients with HS were identifie d. Setting: All hospitals in Sweden. Design: With record linkage to the Swedish National Cancer Registry, standa rdized incidence ratios (SIR [the ratio of the observed to expected inciden ce]) were calculated to estimate relative risk. Results: The risk of developing ally cancer in the cohort with HS increased 50% (95% confidence interval of SIR, 1.1-1.8, based on 73 observed cases). Statistically significant risk elevations were observed for nonmelanoma sk in cancer (5 cases; SIR, 4.6; 95% confidence interval, 1.5-10.7), buccal ca ncer (5 cases; SIR, 5.5; 95% confidence interval, 1.8-12.9), and primary li ver cancer (3 cases; SIR, 10.0; 95% confidence interval, 2.1-29.2). Conclusions: This study confirms an increased risk of nonmelanoma skin canc er among patients with HS. The risk for buccal cancer and primary liver can cer was also elevated among this cohort, but these associations should be i nterpreted cautiously because the combination of multiple significance rest ing and the few observed cases may have generated chance findings.