Is history of squamous-cell skin cancer a marker of poor prognosis in patients with cancer?

Background: Nonmelanoma skin cancer is associated with increased occurrence of subsequent cancer and death from cancer, but it is not known whether a history of skin cancer is associated with poor prognosis after a second diagnosis of cancer. Objective: To determine whether history of squamous-cell skin cancer is a marker of poor prognosis in patients with cancer. Design: Population-based cohort study. Setting: Sweden, 1958 to 1996. Patients: All patients in the Swedish Cancer Registry with or without a first diagnosis of squamous-cell skin cancer and a subsequent or first diagnosis of non-Hodgkin lymphoma (including chronic lymphocytic leukemia) or cancer of the colon, breast, prostate, or lung. Measurements: Relative risk (RR) for death determined by using Cox proportional hazards regression analysis. Results: Patients with a history of squamous-cell skin cancer had a significantly greater risk for death than those with no such history after receiving a diagnosis of non-Hodgkin lymphoma (RR, 1.33). colon cancer (RR, 1.24), breast cancer (RR, 1.19), or prostate cancer (RR, 1.17). Patients with lung cancer and a history of squamous-cell skin cancer who survived for 1 year after diagnosis of lung cancer also had an increased risk for death (RR, 1.29). Conclusion: Patients with a registered history of squamous-cell skin cancer have a poor prognosis after diagnosis of subsequent cancer and warrant careful medical attention.