Solid and Hematologic Neoplasms After Testicular Cancer: A US Population-Based Study of 24 900 Survivors
Michael T. Milano, Paul C. Dinh, Hongmei Yang, Mohammad Abu Zaid, Sophie D. Fosså, Darren R. Feldman, Patrick O. Monahan, Lois B. Travis, Chunkit Fung
Abstract
Abstract Background No large US population-based study focusing on recent decades, to our knowledge, has comprehensively examined risks of second malignant solid and hematological neoplasms (solid-SMN and heme-SMN) after testicular cancer (TC), taking into account initial therapy and histological type. Methods Standardized incidence ratios (SIR) vs the general population and 95% confidence intervals (CI) for solid-SMN and heme-SMN were calculated for 24 900 TC survivors (TCS) reported to the National Cancer Institute’s Surveillance, Epidemiology, and End Results registries (1973–2014). All statistical tests were two-sided. Results The median age at TC diagnosis was 33 years. Initial management comprised chemotherapy (n = 6340), radiotherapy (n = 9058), or surgery alone (n = 8995). During 372 709 person-years of follow-up (mean = 15 years), 1625 TCS developed solid-SMN and 228 (107 lymphomas, 92 leukemias, 29 plasma cell dyscrasias) developed heme-SMN. Solid-SMN risk was increased 1.06-fold (95% CI = 1.01 to 1.12), with elevated risks following radiotherapy (SIR = 1.13, 95% CI = 1.06 to 1.21) and chemotherapy (SIR = 1.36, 95% CI = 1.12 to 1.41) but not surgery alone (SIR = 0.83, 95% CI = 0.75 to 0.92). Corresponding risks for seminoma were 1.13 (95% CI = 1.06 to 1.21), 1.28 (95% CI = 1.02 to 1.58), and 0.87 (95% CI = 0.74 to 1.01) and for nonseminoma were 1.05 (95% CI = 0.67 to 1.56), 1.25 (95% CI = 1.08 to 1.43), and 0.80 (95% CI = 0.70 to 0.92), respectively. Thirty-year cumulative incidences of solid-SMN after radiotherapy, chemotherapy, and surgery alone were 16.9% (95% CI = 15.7% to 18.1%), 10.1% (95% CI = 8.8% to 11.5%), and 8.8% (95% CI = 7.8% to 9.9%), respectively (P < .0001). Increased leukemia risks after chemotherapy (SIR = 2.68, 95% CI = 1.70 to 4.01) were driven by statistically significant sevenfold excesses of acute myeloid leukemia 1 to 10 years after TC diagnosis. Risks for lymphoma and plasma cell dyscrasias were not elevated. Conclusions We report statistically significant excesses of solid-SMN affecting 1 in 6 TCS 30 years after radiotherapy, and 2.7-fold risks of leukemias after chemotherapy, mostly acute myeloid leukemia. Efforts to minimize chemotherapy and radiotherapy exposures for TC should continue. TCS should be counseled about cancer prevention and screening.