Risk of second primary malignancies among cancer survivors in the United States, 1992-2008

Abstract

BACKGROUND. We sought to describe the incidence, most common sites, and mortality of second primary malignancies among survivors of common cancers. METHODS. We identified patients ≥18 years old diagnosed with a primary malignancy from the 10 most common cancer sites (prostate, breast, lung, colon, rectum, bladder, uterus, kidney, melanoma and non-Hodgkin lymphoma) in 1992–2008 from Surveillance, Epidemiology, and End Results (SEER) data. We explored factors associated with the incidence of second primary malignancies using bivariable and multivariable models, and examined mortality attributable to first and second primary malignanices. RESULTS. We identified a cohort of 2,116,163 patients, of whom 170,865 (8.1%) developed a second primary malignancy. Bladder cancer survivors had the highest risk for a second cancer. In a multivariable model controlling for age, race, grade, stage, marital status, education, and income, a history of non-Hodgkin lymphoma (HR 2.70 and 2.88, men and women respectively) and bladder cancer (HR 1.88 and 1.66, men and women respectively) predicted the highest risk for deveping a second cancer. For patients with two incident cancers, 13% died from their initial cancer, but more than half (55%) died from their second primary malignancy. Lung cancer was the cause of death in 12% of patients with two incident cancers. CONCLUSION. Nearly 1 in 12 patients diagnosed with a common cancer developed a second malignancy, the most common of which was lung cancer. More than half of patients with two incident cancers died from their secondary malignancy. Our findings may inform care strategies among cancer survivors.