Secondary lung tumors in hematological patients

Advances made in the field of chemotherapy and radiotherapy have considerably increased the survival of patients with Hodgkin's disease (HD), non-Hodgkin's lymphoma (NHL), and chronic lymphocytic leukemia (CLL). Unfortunately, these antiblastic therapies have also increased the risk of late complications such as second tumors, especially second lung cancers. Although the role of ionizing radiations in carcinogenesis is now clear, less is known about the damage caused by chemotherapy, immunodeficiency induced by drugs or hematological pathologies, and cigarette smoking. In HD, the relative risk (RR) of second lung cancer increases considerably in relation to the dose of ionizing radiation given to the patient, with an RR of 9.6 when more than 9 Gy are administered. Some studies have reported a significantly higher risk of second lung cancers in smokers compared with nonsmokers ( p = .03). The role of chemotherapy in the development of second lung cancers has yet to be determined. Although some authors correlate a greater risk with an increased number of chemotherapy cycles, others maintain that chemotherapy increases the risk of second lung cancer only if associated with cigarette smoking. Even less is known about the correlation between NHL and second lung cancer. Although the RR is higher in long-term NHL survivors than in healthy individuals (RR = 1.36), the heterogeneity of histotype and treatment does not permit us to confirm a correlation with chemotherapy and smoking. Conversely, in CLL, the development of second lung cancer appears to be linked to the immunodeficiency that accompanies this hematological malignancy. This is confirmed by the identical RR (1.66) for CLL patients subjected to chemotherapy and for those who have only follow-up.