Wendy Cozen

Abstract 867: Reproductive factors and risk of B-cell non-Hodgkin lymphoma among women in Los Angeles

Background: Overall, non-Hodgkin lymphoma (NHL) incidence is higher in men than women, and the male to female ratio differs by NHL subtype. Historically, female reproductive characteristics and patterns have been inconsistently linked to NHL risk, though studies on this topic remain limited. Because a woman experiences changes in immune function during pregnancy, that permit her to establish and maintain a successful pregnancy, we hypothesize that such pregnancy-associated changes in immune function could affect the risk of NHL, a cancer of the immune cells. Methods: We conducted a population-based case-control study among women in Los Angeles County comprising 998 histologically confirmed B-cell NHL patients diagnosed 2004-2008 from the Los Angeles Cancer Surveillance Program and 998 individually matched controls (matched on age, race and socioeconomic status). Conditional logistic regression was used to calculate the associations [odds ratios (OR) and 95% confidence intervals (CI)] between female reproductive factors (e.g., ever pregnant; number of full-term pregnancies; breastfeeding) with B-cell NHL overall and unconditional logistic regression was used to calculate the associations with major NHL subtypes. Results: Compared to women who had never been pregnant, women who had full-term pregnancies had 17% decreased risk of B-cell NHL (OR = 0.83, 95% CI = 0.64-1.08); the decreased risk was most pronounced for the diffuse large B-cell lymphoma (DLBCL) subtype (OR = 0.68, 95% CI = 0.47-0.98). Increasing number of full-term pregnancies was inversely associated with B-cell NHL overall (P-trend = 0.02), DLBCL (P-trend = 0.03) and follicular lymphoma (P-trend = 0.04). Women who had reported breastfeeding also had decreased risk of B-cell NHL overall (OR = 0.80, 95% CI = 0.64-1.00) and follicular lymphoma (OR = 0.71, 95% CI = 0.50-1.00). Among women who had full-term pregnancies, women who breastfed for 60 weeks or more had 30% decreased risk of B-cell NHL overall (OR = 0.70, 95% CI = 0.52-0.93; P-trend = 0.06), which was consistent for follicular lymphoma and chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). Conclusions: Our results provide evidence for an association between female reproductive factors and decreased risk of B-cell NHL, supporting a role for hormonal factors in B-cell NHL etiology. Citation Format: Yani Lu, Jianning Luo, Sophia Wang, Jane Sullivan-Halley, Wendy Cozen, Leslie Bernstein. Reproductive factors and risk of B-cell non-Hodgkin lymphoma among women in Los Angeles. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 867. doi:10.1158/1538-7445.AM2015-867

Abstract 2918: Menopausal hormone therapy and B-cell non-Hodgkin lymphoma (NHL) risk in the Los Angeles County NHL Case-Control Study

Introduction: Immune modulation has long been established as a risk factor for non-Hodgkin lymphoma (NHL). Menopausal hormone therapy (MHT) has been shown to affect immune function in both animal and human studies. However, the evidence for an association between MHT and NHL remains unclear. Cohort studies have suggested either no association or increased risk between MHT use and NHL, particularly for the follicular lymphoma subtype. A recent pooled analysis of case-control studies from the United States, Europe, and Australia reported a decreased risk for NHL among women who used MHT, but this analysis was limited by the lack of information on MHT formulation, dose, and duration. Methods: The Los Angeles County NHL Case-Control Study comprises 1010 B-cell NHL patients diagnosed 2004-2008 from the Los Angeles Cancer Surveillance Program, matched 1:1 by age and race to female neighborhood controls. Extensive information on MHT use was ascertained, along with information on demographic and known NHL risk factors. Among 685 post-menopausal women diagnosed with NHL and 685 matched controls, we conducted conditional logistic regression, adjusting for age, race and socioeconomic status, to evaluate the association between MHT use, formulation, dose and duration, and risk for B-cell NHL. Results: B-cell NHL risk was reduced among women who reported having ever used MHT (HR = 0.66, 95% CI = 0.52-0.85) compared to never users. This risk reduction was similar for women who reported using unopposed estrogen only (HR = 0.75, 95% CI =0.56-1.01), estrogen plus progestin only (HR=0.62, 95% CI =0.45-0.85), sequential use of unopposed estrogen followed by estrogen plus progestin (HR=0.36, 95% CI=0.18-0.70), and sequential use of unopposed estrogen plus progestin followed by unopposed estrogen (HR=0.57, 95% CI=0.32-1.00). Among women who reported using unopposed estrogen or estrogen plus progestin by pill or patch (prescription only), reduced B-cell NHL risk was most pronounced among those who started MHT use early, at age 45 years or younger (HR=0.60, 95% CI=0.42-0.85) and generally among women with longer duration of use. The protective associations associated with MHT use were consistent among major B-cell NHL subtypes, including diffuse large B-cell lymphoma and follicular lymphoma. Conclusions: These data provide evidence for an association between MHT use - either unopposed estrogen or estrogen plus progestin use - and decreased risk of B-cell NHL, supporting a role for postmenopausal hormones in B-cell NHL etiology. Citation Format: Sophia S. Wang, Jianning Luo, Jane Sullivan-Halley, Yani Lu, James V. Lacey, Jr., Wendy Cozen, Leslie Bernstein. Menopausal hormone therapy and B-cell non-Hodgkin lymphoma (NHL) risk in the Los Angeles County NHL Case-Control Study. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2918. doi:10.1158/1538-7445.AM2014-2918