Background and Aims
Gallbladder cancer (GBC) has a female predominance, whereas the other biliary tract cancers (BTCs) have a male predominance, suggesting that sex hormones may be involved in ...carcinogenesis. We sought to evaluate the association between menopausal hormone therapy (MHT) and the risk of BTC in women.
Approach and Results
This nested case‐control study was conducted in the UK Clinical Practice Research Datalink. Cases diagnosed between 1990 and 2017 with incident primary cancers of the gallbladder (GBC), cholangiocarcinoma (CCA), ampulla of Vater (AVC), and mixed type were matched to 5 controls on birth year, diagnosis year, and years in the general practice using incidence density sampling. Conditional logistic regression was used to calculate ORs and 95% CIs for associations between MHT use and BTC type. The sample consisted of 1,682 BTC cases (483 GBC, 870 CCA, 105 AVC, and 224 mixed) and 8,419 matched controls with a mean age of 73 (SD, 11) years. Combined formulations (estrogen‐progesterone) were associated with an increased GBC risk (OR, 1.97; 95% CI, 1.08, 3.59). Orally administered MHT was associated with an increased GBC risk (OR, 2.28; 95% CI, 1.24, 4.17). Estrogen‐only formulations (OR, 0.59; 95% CI, 0.34, 0.93) and cream or suppository administrations (OR, 0.57; 95% CI, 0.34, 0.95) were associated with decreased CCA risk. The number of prescriptions, dose, duration of use, and time since last use were not associated with GBC or CCA risk. MHT use was not associated with risk of AVC or mixed cancer.
Conclusions
Combination MHT formulations and oral administrations were associated with increased GBC risk, whereas estrogen‐only formulations were associated with a lower CCA risk. MHT formulation and administration should be carefully considered when prescribing.
Esophageal adenocarcinoma (EA) is characterized by a strong male predominance. Sex steroid hormones have been hypothesized to underlie this sex disparity, but no population-based study to date has ...examined this potential association.
Using mass spectrometry and ELISA, we quantitated sex steroid hormones and sex hormone binding globulin, respectively, in plasma from males- 172 EA cases and 185 controls-within the Factors Influencing the Barrett/Adenocarcinoma Relationship (FINBAR) Study, a case-control investigation conducted in Northern Ireland and Ireland. Multivariable adjusted logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for associations between circulating hormones and EA.
Higher androgen:estrogen ratio metrics were associated with increased odds of EA (e.g., testosterone:estradiol ratio ORQ4 v. Q1 = 2.58, 95%CI = 1.23-5.43; Ptrend = 0.009). All estrogens and androgens were associated with significant decreased odds of EA. When restricted to individuals with minimal to no decrease in body mass index, the size of association for the androgen:estrogen ratio was not greatly altered.
This first study of sex steroid hormones and EA provides tentative evidence that androgen:estrogen balance may be a factor related to EA. Replication of these findings in prospective studies is needed to enhance confidence in the causality of this effect.
Incorporation of polygenic risk scores and mammographic density into models to predict breast cancer incidence can increase discriminatory accuracy (area under the receiver operating characteristic ...curve AUC) from 0.6 for models based only on epidemiologic factors to 0.7. It is timely to assess what impact these improvements will have on individual counseling and on public health prevention and screening strategies, and to determine what further improvements are needed.
We studied various clinical and public health applications using a log-normal distribution of risk.
Provided they are well calibrated, even risk models with AUCs of 0.6 to 0.7 provide useful perspective for individual counseling and for weighing the harms and benefits of preventive interventions in the clinic. At the population level, they are helpful for designing preventive intervention trials, for assessing reductions in absolute risk from reducing exposure to modifiable risk factors, and for resource allocation (although a higher AUC would be desirable for risk-based allocation). Other public health applications require higher AUCs that can only be achieved with risk predictors 1.6 to 8.8 times as strong as all those yet discovered combined. Such applications are preventing an appreciable proportion of population disease when employing a high-risk prevention strategy and deciding who should be screened for subclinical disease.
Current and foreseeable risk models are useful for counseling and some prevention activities, but given the daunting challenge of achieving, for example, an AUC of 0.8, considerable effort should be put into finding effective preventive interventions and screening strategies with fewer adverse effects.
Typically, case‐control studies to estimate odds‐ratios associating risk factors with disease incidence only include newly diagnosed cases. Recently proposed methods allow incorporating information ...on prevalent cases, individuals who survived from disease diagnosis to sampling, into cross‐sectionally sampled case‐control studies under parametric assumptions for the survival time after diagnosis. Here we propose and study methods to additionally use prospectively observed survival times from prevalent and incident cases to adjust logistic models for the time between diagnosis and sampling, the backward time, for prevalent cases. This adjustment yields unbiased odds‐ratio estimates from case‐control studies that include prevalent cases. We propose a computationally simple two‐step generalized method‐of‐moments estimation procedure. First, we estimate the survival distribution assuming a semiparametric Cox model using an expectation‐maximization algorithm that yields fully efficient estimates and accommodates left truncation for prevalent cases and right censoring. Then, we use the estimated survival distribution in an extension of the logistic model to three groups (controls, incident, and prevalent cases), to adjust for the survival bias in prevalent cases. In simulations, under modest amounts of censoring, odds‐ratios from the two‐step procedure were equally efficient as those estimated from a joint logistic and survival data likelihood under parametric assumptions. This indicates that utilizing the cases' prospective survival data lessens model dependencies and improves precision of association estimates for case‐control studies with prevalent cases. We illustrate the methods by estimating associations between single nucleotide polymorphisms and breast cancer risk using controls, and incident and prevalent cases sampled from the US Radiologic Technologists Study cohort.
Antiretroviral therapy (ART) has reduced mortality among people living with human immunodeficiency virus (HIV), but cancer remains an important cause of death. We characterized cancer-attributable ...mortality in the HIV population during 2001-2015.
We used data from population-based HIV and cancer registries in the United States (US). Cox proportional hazards regression models were used to estimate adjusted hazard ratios (HRs) associating cancer diagnoses with overall mortality, we could perhaps cut these words to accommodate the word limit. However readers will probably want to know what statistical adjustments were made to the model. Population-attributable fractions (PAFs) were calculated using these HRs and the proportion of deaths preceded by cancer. Cancer-specific PAFs and cancer-attributable mortality rates were calculated for demographic subgroups, AIDS-defining cancers (Kaposi sarcoma KS, non-Hodgkin lymphoma NHL, cervical cancer), and non-AIDS-defining cancers.
Cancer-attributable mortality was 386.9 per 100 000 person-years, with 9.2% and 5.0% of deaths attributed to non-AIDS-defining and AIDS-defining cancers, respectively. Leading cancer-attributable deaths were from NHL (3.5%), lung cancer (2.4%), KS (1.3%), liver cancer (1.1%), and anal cancer (0.6%). Overall, cancer-attributable mortality declined from 484.0 per 100 000 person-years during 2001-2005 to 313.6 per 100 000 person-years during 2011-2015, while the PAF increased from 12.6% to 17.1%; the PAF for non-AIDS-defining cancers increased from 7.2% to 11.8% during 2011-2015. Cancer-attributable mortality was highest among those aged ≥60 years (952.2 per 100 000 person-years), with 19.0% of deaths attributed to non-AIDS-defining cancers.
Although cancer-attributable mortality has declined over time, it remains high and represents a growing fraction of deaths in the US HIV population. Mortality from non-AIDS-defining cancers may rise as the HIV population ages. ART access, early cancer detection, and improved cancer treatment are priorities for reducing cancer-attributable mortality.
Monoclonal gammopathy of undetermined significance (MGUS) is a premalignant plasma-cell proliferative disorder associated with a life-long risk of progression to multiple myeloma (MM). It is not ...known whether MM is always preceded by a premalignant asymptomatic MGUS stage. Among 77 469 healthy adults enrolled in the nationwide population-based prospective Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial, we identified 71 subjects who developed MM during the course of the study in whom serially collected (up to 6) prediagnostic serum samples obtained 2 to 9.8 years prior to MM diagnosis were available. Using assays for monoclonal (M)–proteins (electrophoresis/immunofixation) and kappa-lambda free light chains (FLCs), we determined longitudinally the prevalence of MGUS and characterized patterns of monoclonal immunoglobulin abnormalities prior to MM diagnosis. MGUS was present in 100.0% (87.2%-100.0%), 98.3% (90.8%-100.0%), 97.9% (88.9%-100.0%), 94.6% (81.8%-99.3%), 100.0% (86.3%-100.0%), 93.3% (68.1%-99.8%), and 82.4% (56.6%-96.2%) at 2, 3, 4, 5, 6, 7, and 8+ years prior to MM diagnosis, respectively. In approximately half the study population, the M-protein concentration and involved FLC-ratio levels showed a yearly increase prior to MM diagnosis. In the present study, an asymptomatic MGUS stage consistently preceded MM. Novel molecular markers are needed to better predict progression to MM in patients with MGUS.
Effective antiretroviral therapy has reduced the risk of AIDS and dramatically prolonged the survival of HIV-infected people in the United States. Consequently, an increasing number of HIV-infected ...people are at risk of non-AIDS-defining cancers that typically occur at older ages. We estimated the annual number of cancers in the HIV-infected population, both with and without AIDS, in the United States.
Incidence rates for individual cancer types were obtained from the HIV/AIDS Cancer Match Study by linking 15 HIV and cancer registries in the United States. Estimated counts of the US HIV-infected and AIDS populations were obtained from Centers for Disease Control and Prevention surveillance data. We obtained estimated counts of AIDS-defining (ie, Kaposi sarcoma, non-Hodgkin lymphoma, and cervical cancer) and non-AIDS-defining cancers in the US AIDS population during 1991-2005 by multiplying cancer incidence rates and AIDS population counts, stratified by year, age, sex, race and ethnicity, transmission category, and AIDS-relative time. We tested trends in counts and standardized incidence rates using linear regression models. We multiplied overall cancer rates and HIV-only (HIV infected, without AIDS) population counts, available from 34 US states during 2004-2007, to estimate cancers in the HIV-only population. All statistical tests were two-sided.
The US AIDS population expanded fourfold from 1991 to 2005 (96,179 to 413,080) largely because of an increase in the number of people aged 40 years or older. During 1991-2005, an estimated 79 656 cancers occurred in the AIDS population. From 1991-1995 to 2001-2005, the estimated number of AIDS-defining cancers decreased by greater than threefold (34,587 to 10,325 cancers; P(trend) < .001), whereas non-AIDS-defining cancers increased by approximately threefold (3193 to 10,059 cancers; P(trend) < .001). From 1991-1995 to 2001-2005, estimated counts increased for anal (206 to 1564 cancers), liver (116 to 583 cancers), prostate (87 to 759 cancers), and lung cancers (875 to 1882 cancers), and Hodgkin lymphoma (426 to 897 cancers). In the HIV-only population in 34 US states, an estimated 2191 non-AIDS-defining cancers occurred during 2004-2007, including 454 lung, 166 breast, and 154 anal cancers.
Over a 15-year period (1991-2005), increases in non-AIDS-defining cancers were mainly driven by growth and aging of the AIDS population. This growing burden requires targeted cancer prevention and treatment strategies.
Purpose People with HIV infection have an elevated risk of anal cancer. However, recent calendar trends are incompletely described, and which population subgroups might benefit from cancer screening ...is unknown. Methods We used linked data from HIV and cancer registries in nine US areas (1996 to 2012). We calculated standardized incidence ratios to compare anal cancer incidence in people with HIV infection with the general population, used Poisson regression to evaluate anal cancer incidence among subgroups of people with HIV and to assess temporal trends, and estimated the cumulative incidence of anal cancer to measure absolute risk. Results Among 447,953 people with HIV infection, anal cancer incidence was much higher than in the general population (standardized incidence ratio, 19.1; 95% CI, 18.1 to 20.0). Anal cancer incidence was highest among men who have sex with men (MSM), increased with age, and was higher in people with AIDS than in those without AIDS (ie, HIV only; adjusted incidence rate ratio, 3.82; 95% CI, 3.27 to 4.46). Incidence among people with HIV increased steeply during 1996 to 2000 (annual percentage change, 32.8%; 95% CI, -1.0% to 78.2%), reached a plateau during 2001 to 2008, and declined during 2008 to 2012 (annual percentage change, -7.2%; 95% CI, -14.4% to 0.6%). Cumulative incidence after a 5-year period was high for MSM with HIV only age 45 to 59 or ≥ 60 years (0.32% to 0.33%) and MSM with AIDS age 30 to 44, 45 to 59, or ≥ 60 years (0.29% to 0.65%). Conclusion Anal cancer incidence is markedly elevated among people with HIV infection, especially in MSM, older individuals, and people with AIDS. Recent declines may reflect delayed benefits of HIV treatment. Groups with high cumulative incidence of anal cancer may benefit from screening.
In epidemiologic studies, association estimates of an exposure with disease outcomes are often biased when the uncertainties of exposure are ignored. Consequently, corresponding confidence intervals ...(CIs) will not have correct coverage. This issue is particularly problematic when exposures must be reconstructed from physical measurements, for example, for environmental or occupational radiation doses that were received by a study population for which radiation doses cannot be measured directly. To incorporate complex uncertainties in reconstructed exposures, the two-dimensional Monte Carlo (2DMC) dose estimation method has been proposed and used in various dose reconstruction efforts. The 2DMC method generates multiple exposure realizations from dosimetry models that incorporate various sources of errors to reflect the uncertainty of the dose distribution as well as the uncertainties in individual doses in the exposed population. Traditional measurement-error model approaches, typically based on using mean doses in the dose-exposure analysis, do not fully account exposure uncertainties. A recently developed statistical approach that overcomes many of these limitations by analyzing multiple exposure realizations in relation to disease risk is Bayesian model averaging (BMA). The analytic advantage of the BMA is its ability to better accommodate complex exposure uncertainty in the risk estimation, but a practical. Drawback is its significant computational complexity. In this present paper, we propose a novel frequentist model averaging (FMA) approach which has all the analytical advantages of the BMA method but is much simpler to implement and computationally faster. We show in simulations that, like BMA, FMA yields 95% confidence intervals for association parameters that close to 95% coverage rate. In simulations, the FMA has shorter length of CIs than those of another frequentist approach, the corrected information matrix (CIM) method. We illustrate the similarities in performance of BMA and FMA from a study of exposures from radioactive fallout in Kazakhstan.
PDF
