The risk of secondary malignancies over 30 years after the treatment of non-Hodgkin lymphoma
Cancer. 2006 May 17; [Epub ahead of print] [Link]
Tward JD, Wendland MM, Shrieve DC, Szabo A, Gaffney DK.
Department of Radiation Oncology, Huntsman Cancer Hospital, University of Utah, Salt Lake City, Utah.
Background: Survivors of non-Hodgkin lymphoma (NHL) are at increased risk for developing secondary malignancies. For the current study, the authors quantitated this risk in a group of NHL survivors over 30 years of follow-up.
Methods: Standardized incidence ratios (observed-to-expected [O/E] ratio) and absolute excess risk of secondary malignancies were assessed in 77,876 patients who were diagnosed with NHL between 1973 and 2001 from centers that participated in the National Cancer Institute’s Surveillance, Epidemiology, and End Results Program.
Results: There were 5638 patients who developed secondary malignancies, significantly more than the endemic rate (O/E, 1.14; P<.001). Overall, irradiated patients had a similar risk of secondary malignancies compared with unirradiated patients (relative risk, 1.04; 95% confidence interval, 0.98-1.10; P = .21). Irradiated patients had excess risk for sarcomas, breast cancers, and mesothelioma compared with unirradiated survivors (P<.05). Patients age <25 years at the time of their NHL diagnosis had the highest relative increased risk (no radiation: O/E, 2.1; P<.05; radiation: O/E, 4.51; P<.05). Overall, no statistical difference was observed for secondary cancer incidence between females and males (O/E, 1.12 vs. 1.15, respectively). Female survivors of NHL were less likely to develop breast cancer than the general population (O/E, 0.85; P<.05), but women age <25 years at the time of their NHL diagnosis were more likely to develop breast cancer (no radiation: O/E, 2.1; P<.05; radiation: O/E, 4.51; P<.05).
Conclusions: The overall risk of secondary malignancies was increased for NHL survivors and varied according to age at NHL diagnosis, gender, and treatment.
Keywords: absolute excess risk; observed-to-expected ratio; second malignancies; standardized incidence ratio; Surveillance, Epidemiology, and End Results Program