Family history of hematopoietic and non-hematopoietic malignancies and risk of non-Hodgkin lymphoma

Background Family history of hematopoietic malignancies has been linked to the risk of non-Hodgkin lymphoma (NHL). The relationship between family history of specific hematopoietic and non-hematopoietic malignancies and the risk of NHL and by NHL subtypes are unclear. Methods We analyzed data from a population-based case–control study in Connecticut women. A total of 601 histologically confirmed NHL incident cases and 717 randomly selected controls were included in the study. Unconditional logistic regression was used to estimate the association between family cancer history and risk of NHL overall and by NHL subtypes. Results Compared to women who reported to have no family history of any malignancies in first-degree relatives, those who reported to have a family history of lymphoma (OR = 2.2, 95%CI: 1.1–4.5) or leukemia (OR = 2.5, 95%CI: 1.2–5.2) had an increased risk of NHL. The risk was higher among women who had a sibling with lymphoma or leukemia than those who had parents with lymphoma or leukemia. Several non-hematopoietic malignancies in first-degree relatives, including cancer of the lung (OR = 1.7, 95%CI: 1.1–2.6) in first-degree relatives, stomach (OR = 2.2, 95%CI: 0.8–5.9) and pancreas (OR = 2.6, 95%CI: 0.9–7.1) in parents, as well as liver (OR = 5.0, 95%CI: 1.0–24.6), breast (OR = 2.2, 95%CI: 1.3–3.9), cervix (OR = 7.5, 95%CI: 0.9–64.9), and ovary (OR = 3.5, 95%CI: 1.1–11.5) in siblings were also associated with an increased risk of NHL. Conclusions The risk associated with a family history of malignancies in first degree-relatives appears to vary by type of first-degree relatives.