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Estimates of the future breast cancer burden preventable through modifications to current behaviours are lacking. We assessed the effect of individual and joint behaviour modifications on breast cancer burden for premenopausal and postmenopausal Australian women, and whether effects differed between population subgroups. We linked pooled data from six Australian cohort studies (n = 214,536) to national cancer and death registries, and estimated the strength of the associations between behaviours causally related to cancer incidence and death using adjusted proportional hazards models. We estimated exposure prevalence from representative health surveys. We combined these estimates to calculate Population Attributable Fractions (PAFs) with 95% confidence intervals (CIs), and compared PAFs for population subgroups. During the first 10 years follow‐up, there were 640 incident breast cancers for premenopausal women, 2,632 for postmenopausal women, and 8,761 deaths from any cause. Of future breast cancers for premenopausal women, any regular alcohol consumption explains 12.6% (CI = 4.3–20.2%), current use of oral contraceptives for ≥5 years 7.1% (CI = 0.3–13.5%), and these factors combined 18.8% (CI = 9.1–27.4%). Of future breast cancers for postmenopausal women, overweight or obesity (BMI ≥25 kg/m2) explains 12.8% (CI = 7.8–17.5%), current use of menopausal hormone therapy (MHT) 6.9% (CI = 4.8–8.9%), any regular alcohol consumption 6.6% (CI = 1.5–11.4%), and these factors combined 24.2% (CI = 17.6–30.3%). The MHT‐related postmenopausal breast cancer burden varied by body fatness, alcohol consumption and socio‐economic status, the body fatness‐related postmenopausal breast cancer burden by alcohol consumption and educational attainment, and the alcohol‐related postmenopausal breast cancer burden by breast feeding history. Our results provide evidence to support targeted and population‐level cancer control activities. What's new? While several potentially‐modifiable behavioural risk factors have been identified for breast cancer, estimates of the preventable future breast cancer burden are still lacking. Based on a large prospective pooled Australian cohort, here the authors reveal that regular alcohol consumption is the leading modifiable cause of breast cancer burden for premenopausal women (12.6%). Using the latest exposure prevalence information, the authors rank body fatness as the leading cause of preventable breast cancer burden for postmenopausal women (12.8%), with regular alcohol consumption also contributing substantially (6.6%). The findings provide evidence to support targeted and population‐level cancer control activities in Australia and beyond. [ABSTRACT FROM AUTHOR]

Evidence on the endometrial and ovarian cancer burden preventable through modifications to current causal behavioural and hormonal exposures is limited. Whether the burden differs by population subgroup is unknown. We linked pooled data from six Australian cohort studies to national cancer and death registries, and quantified exposure-cancer associations using adjusted proportional hazards models. We estimated exposure prevalence from representative health surveys. We then calculated Population Attributable Fractions (PAFs) with 95% confidence intervals (CIs), accounting for competing risk of death, and compared PAFs for population subgroups. During a median 4.9 years follow-up, 510 incident endometrial and 303 ovarian cancers were diagnosed. Overweight and obesity explained 41.9% (95% CI 32.3–50.1) of the endometrial cancer burden and obesity alone 34.5% (95% CI 27.5–40.9). This translates to 12,800 and 10,500 endometrial cancers in Australia in the next 10 years, respectively. The body fatness-related endometrial cancer burden was highest (49–87%) among women with diabetes, living remotely, of older age, lower socio-economic status or educational attainment and born in Australia. Never use of oral contraceptives (OCs) explained 8.1% (95% CI 1.8–14.1) or 2500 endometrial cancers. A higher BMI and current long-term MHT use increased, and long-term OC use decreased, the risk of ovarian cancer, but the burden attributable to overweight, obesity or exogenous hormonal factors was not statistically significant. Excess body fatness, a trait that is of high and increasing prevalence globally, is responsible for a large proportion of the endometrial cancer burden, indicating the need for effective strategies to reduce adiposity. • Contemporary estimates of endometrial cancer burden attributable to body fatness. • Overweight and obesity explain 42%, and obesity alone explains 35% of endometrial cancers. • First estimates of future endometrial cancer burden for population subgroups. • Overweight and obesity explain 49–87% of the endometrial cancer burden for some subgroups of women. [ABSTRACT FROM AUTHOR]

Iatrogenic immunosuppression is a strong risk factor for non-Hodgkin lymphoma ( NHL) but the dose-related association between individual immunosuppressive agents and NHL risk is unknown. We conducted a population-based cohort study of 4131 adult Australian liver, heart and lung transplant recipients (1984-2006). We ascertained NHL incidence by probabilistic record linkage between transplant registries and the Australian Cancer Database, and abstracted risk factor data at transplantation and at regular intervals thereafter from medical records. We estimated adjusted hazard ratios ( HR) for early (<1 year after transplantation; n = 29) and late (≥1 year; n = 61) NHL using the Fine and Gray proportional subdistribution hazards model that accounted for death as a competing risk. After adjustment for immunosuppression, the risk of both early and late NHL did not significantly differ by organ type. In final models, higher mean daily doses of azathioprine were associated with increased risk of both early [ HR 2·20, 95% confidence interval ( CI): 1·21-4·01] and late NHL ( HR 1·78, 95% CI: 1·12-2·84). There was no association between any other maintenance immunosuppressive agent and NHL risk. This study provides evidence that differences in immunosuppression may explain variation in NHL incidence by organ type, and high doses of azathioprine may independently predict NHL risk. [ABSTRACT FROM AUTHOR]

Unconfounded comparative data on the type and dose of immunosuppressive agents among solid organ transplant recipients are sparse, as are data on longitudinal immunosuppressive therapy since transplantation. We addressed this issue in a population-based cohort of Australian liver (n = 1895), heart (n = 1220), and lung (n = 1059) transplant recipients, 1984-2006. Data on immunosuppressive therapy were retrospectively collected at discharge, three months, and one, five, 10, and 15 yr after first transplant. We computed unadjusted and adjusted estimates for the association between the type and dose of immunosuppressive therapy and organ type. After adjustment for confounders, use of induction antibody and maintenance corticosteroids was more common in heart and lung compared to liver recipients (p < 0.001), and antibody therapy for rejection more common in liver recipients (p < 0.001). Liver recipients were more likely to receive calcineurin inhibitor monotherapy, with or without corticosteroids, compared to heart and lung recipients (p < 0.001). Liver recipients consistently received lower doses of azathioprine than heart and lung recipients (p < 0.001). These differences in immunosuppression may partly explain variations in immunosuppression-related morbidity by transplanted organ, for example, malignancy risk. Longitudinal changes in the type and the dose of immunosuppressive therapy over time since transplantation also demonstrate the need for time-dependent data in observational research. [ABSTRACT FROM AUTHOR]

Background: Most cohort studies investigating the effect of immunosuppression on transplant outcomes use drugs at first hospital discharge. We evaluated the extent of drug exposure misclassification and its impact on outcome prediction. Methods: We retrospectively collected longitudinal immunosuppression data, at discharge and at 1, 5, 10, and 15 years after transplantation, and outcomes for solid organ transplant recipients 1984‐2006 (n = 3133). We compared the risk of death from exposure to individual immunosuppressive drugs (cyclosporine, tacrolimus, azathioprine, and mycophenolate) and dual therapies, as defined by discharge only vs longitudinal immunosuppression data, using adjusted Cox proportional hazards models. Results: During a median follow‐up of 5.2 years, immunosuppressive drugs were altered for 947 (30%) recipients and 955 recipients died. Longitudinal receipt of cyclosporine and azathioprine were associated with an increased risk (HR 1.41, 95% CI 1.07‐1.89, and HR 1.34, 95% CI 1.00‐1.80), and mycophenolate with a reduced risk (HR 0.35, 0.16‐0.78), of death. Recipients on mycophenolate and tacrolimus dual therapy had a lower risk of death compared to those on azathioprine and cyclosporine dual therapy (HR 0.30, 0.10‐0.93). The increased risk of death associated with the receipt of cyclosporine or azathioprine was not shown in the analyses based on drugs allocated at discharge, and all of the associations between immunosuppressive regimens and death were strengthened in the analyses based on longitudinal immunosuppression data. Conclusions: Cohort findings based on immunosuppressive drugs allocated at discharge should be interpreted with caution due to potential exposure misclassification. The use of granular, longitudinal data on immunosuppressive regimens could improve prediction. [ABSTRACT FROM AUTHOR]

Background: Iatrogenic immunosuppression is a risk factor for lip cancer but the determinants are unknown.Objective: We sought to quantify the association between the type, dose, and duration of iatrogenic immunosuppression and lip cancer risk in solid organ transplant recipients.Methods: We conducted a population-based cohort study of all adult Australian liver, heart, and lung transplant recipients from 1984 to 2006 (n = 4141). We abstracted longitudinal data from medical records and ascertained incident lip cancer (n = 58) and deaths (n = 1434) by linkage with national registries. We estimated multivariable hazard ratios (HR) for lip cancer using the Fine and Gray proportional subdistribution hazards model, accounting for death as a competing risk.Results: Lip cancer risk (n = 58) increased with high mean daily dose of azathioprine (HR 2.28, 95% confidence interval [CI] 1.18-4.38), longer duration of immunosuppression (HR 9.86, 95% CI 2.10-46.3), increasing year of age at transplantation (HR 1.14, 95% CI 1.04-1.25), earlier transplantation era (HR 8.73, 95% CI 1.11-68.7), and history of smoking (HR 2.71, 95% CI 1.09-6.70).Limitations: Data on potential confounders such as personal solar ultraviolet radiation exposure were not available.Conclusion: Higher doses of azathioprine increase lip cancer risk, with implications for managing immunosuppressed populations and our understanding of the relationship between solar ultraviolet radiation and lip cancer. [ABSTRACT FROM AUTHOR]