Reproductive factors and risk of biliary tract cancer in a population-based study

Menopausal hormone therapy increases the risk of gallstones: Health Insurance Database in South Korea (HISK)-based cohort study

OBJECTIVE

To determine whether menopausal hormone therapy (MHT) increases the risk of gallstones and gallbladder cancer.

DESIGN

A retrospective cohort study.

PATIENTS OR OTHER PARTICIPANTS

Data from the Korea National Health Insurance Corporation was obtained between January 1, 2002, and December 31, 2019.

INTERVENTIONS

Participants were divided into MHT and non-MHT groups; the MHT group was analyzed in detail by dividing participants into tibolone, combined estrogen plus progestin by the manufacturer (CEPM) or physician (CEPP), oral estrogen alone, and topical estrogen subgroups.

MAIN OUTCOME MEASURES

The incidence of gallstones and gallbladder cancer was compared between the two groups.

RESULTS

This study enrolled 1,004,034 and 381,711 patients in the non-MHT and the MHT groups, respectively. The incidence of gallstones was 2.6% in the non-MHT group and 3.4%, 2.6%, 3.4%, 3.2%, and 4.4% in the tibolone, CEPM, oral estrogen alone, CEPP, and topical estrogen groups, respectively. Cox proportional hazard analysis revealed that all hormones increased the risk of gallstones ([tibolone] hazard ratio [HR]: 1.347, 95% confidence interval [CI]: 1.309-1.387, [CEPM] HR: 1.146, 95% CI: 1.1-1.19, [oral estrogen alone] HR: 1.241, 95% CI: 1.18-1.305, [CEPP] HR: 1.164, 95% CI: 1.01-1.341, [topical estrogen] HR: 1.602, 95% CI: 1.295-1.983). However, the risk of gallbladder cancer did not change with any hormone therapy.

CONCLUSIONS

All types of MHT including tibolone, increased the risk of gallstones. This risk was the highest with topical estrogen, which may be a result of selection bias due to concerns regarding the adverse effects of CEE and MPA.

Reproductive factors and gall-bladder cancer, and the effect of common genetic variants on these associations: a case-control study in India

BACKGROUND

In India, as elsewhere, the incidence of gall-bladder cancer (GBC) is substantially higher in women than in men. Yet, the relevance of reproductive factors to GBC remains poorly understood.

METHODS

We used logistic regression adjusted for age, education and area to examine associations between reproductive factors and GBC risk, using 790 cases of histologically confirmed GBC and group-matched 1726 visitor controls. We tested the interaction of these associations by genetic variants known to increase the risk of GBC.

RESULTS

Parity was strongly positively associated with GBC risk: each additional pregnancy was associated with an ∼25% higher risk {odds ratio [OR] 1.26 [95% confidence interval (95% CI) 1.17-1.37]}. After controlling for parity, GBC risk was weakly positively associated with later age of menarche [postmenopausal women, OR 1.11 (95% CI 1.00-1.22) per year], earlier menopause [OR 1.03 (95% CI 1.00-1.06) per year] and shorter reproductive lifespan [OR 1.04 (95% CI 1.01-1.07) per year], but there was little evidence of an association with breastfeeding duration or years since last pregnancy. Risk alleles of single-nucleotide polymorphisms in the ABCB4 and ABCB1 genetic regions had a multiplicative effect on the association with parity, but did not interact with other reproductive factors.

CONCLUSIONS

We observed higher GBC risk with higher parity and shorter reproductive lifespan, suggesting an important role for reproductive and hormonal factors.

Menopausal hormone therapy and risk of biliary tract cancers

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.

Associations between reproductive factors and biliary tract cancers in women from the Biliary Tract Cancers Pooling Project

BACKGROUND & AIMS

Gallbladder cancer (GBC) is known to have a female predominance while other biliary tract cancers (BTCs) have a male predominance. However, the role of female reproductive factors in BTC etiology remains unclear.

METHODS

We pooled data from 19 studies of >1.5 million women participating in the Biliary Tract Cancers Pooling Project to examine the associations of parity, age at menarche, reproductive years, and age at menopause with BTC. Associations for age at menarche and reproductive years with BTC were analyzed separately for Asian and non-Asian women. Hazard ratios (HRs) and 95% CIs were estimated using Cox proportional hazards models, stratified by study.

RESULTS

During 21,681,798 person-years of follow-up, 875 cases of GBC, 379 of intrahepatic bile duct cancer (IHBDC), 450 of extrahepatic bile duct cancer (EHBDC), and 261 of ampulla of Vater cancer (AVC) occurred. High parity was associated with risk of GBC (HR ≥5 vs. 0 births 1.72; 95% CI 1.25-2.38). Age at menarche (HR per year increase 1.15; 95% CI 1.06-1.24) was associated with GBC risk in Asian women while reproductive years were associated with GBC risk (HR per 5 years 1.13; 95% CI 1.04-1.22) in non-Asian women. Later age at menarche was associated with IHBDC (HR 1.19; 95% CI 1.09-1.31) and EHBDC (HR 1.11; 95% CI 1.01-1.22) in Asian women only.

CONCLUSION

We observed an increased risk of GBC with increasing parity. Among Asian women, older age at menarche was associated with increased risk for GBC, IHBDC, and EHBDC, while increasing reproductive years was associated with GBC in non-Asian women. These results suggest that sex hormones have distinct effects on cancers across the biliary tract that vary by geography.

LAY SUMMARY

Our findings show that the risk of gallbladder cancer is increased among women who have given birth (especially women with 5 or more children). In women from Asian countries, later age at menarche increases the risk of gallbladder cancer, intrahepatic bile duct cancer and extrahepatic bile duct cancer. We did not see this same association in women from Western countries. Age at menopause was not associated with the risk of any biliary tract cancers.

Menopausal hormone therapy and biliary tract cancer: a population-based matched cohort study in Sweden

BACKGROUND

This study tested the hypothesis that contemporary menopausal hormonal therapy (MHT) increases the risk of biliary tract cancer. The risk of cancer of the biliary tract (gallbladder and extra-hepatic bile ducts) may be increased following estrogen exposure.

MATERIAL AND METHODS

This was a nationwide population-based matched cohort study in Sweden. Data from the Swedish Prescribed Drug Register identified all women exposed to systemic MHT in 2005-2012. Group-level matching (1:3 ratio) was used to select women unexposed to MHT from the same study base, matched for history of delivery, thrombotic events, hysterectomy, age, smoking- and alcohol related diseases, obesity, and diabetes. Conditional logistic regression was used to calculate odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

Comparing 290,186 women exposed to MHT with 870,165 unexposed, MHT did not increase the OR of biliary tract cancer. The OR of gallbladder cancer was rather decreased in MHT users (OR 0.58, 95% CI 0.43-0.79), but this association became attenuated and statistically non-significant after adjusting for gallstone disease (OR 0.84, 95% CI 0.60-1.15). The OR of extra-hepatic bile duct cancers was 0.83 (95% CI 0.61-1.15). There were no clear differences when the analyses were stratified for estrogen or estrogen/progestogen combinations. MHT increased the risk of gallstone disease (OR 6.95, 95% CI 6.64-7.28).

CONCLUSIONS

Contemporary MHT does not seem to increase the risk of biliary tract cancer. The decreased risk of gallbladder cancer may be explained by the increased use of surgery for symptomatic gallstones in MHT users.

Tea consumption and the risk of biliary tract cancer: a systematic review and dose-response meta-analysis of observational studies

Recent studies have shown that tea consumption is associated with the reduced incidence of some types of cancer, possibly including biliary tract cancer. However, the epidemiological evidences for the association with risk of biliary tract cancer are contradictory. Thus, we performed meta-analysis of published observational studies to assess the association between tea consumption and risk of biliary tract cancer. Relevant studies were identified by searching PubMed, EMBASE, and ISI Web of Science published before October 2016. The Newcastle-Ottawa Scale was used to evaluate the quality of included studies, and publication bias was evaluated using funnel plots, and Begg's and Egger's tests. This meta-analysis includes eight studies comprising 18 independent reports. The incidence of biliary tract cancer reduced about 34% (significantly) for tea intake group in comparison with never intake group (summary odds ratio [OR] = 0.66; 95% confidence interval [CI] = 0.48-0.85). Additionally, an inverse relationship between tea intake and risk of biliary tract cancer was statistically significant in women (OR = 0.65; 95 % CI = 0.47-0.83), but not in men (OR = 0.86; 95% CI = 0.58-1.13). Dose- response analysis indicated that the risk of biliary tract cancer decreased by 4% with each additional cup of tea one day (relative risk [RR] = 0.96, 95% CI = 0.93-0.98, p = 0.001). In summary, tea intake is associated with decreased risk of biliary tract cancer, especially for women.

Exogenous estrogen and the risk of biliary tract cancer - a population-based study in a cohort of Swedish men treated for prostate cancer

BACKGROUND

To assess the role of exogenous estrogen in the etiology of biliary tract cancer, a nationwide population-based cohort study in Sweden was performed.

METHODS

The study included all men in Sweden with prostate cancer diagnosed in 1961-2008. Due to treatment standards, patients diagnosed in 1961-1980 were considered more exposed to estrogen, while those diagnosed in 1981-2008 were regarded less exposed. Standardized incidence ratios (SIRs) with 95% confidence intervals (CIs) were calculated to estimate the risk of biliary tract cancer in cohort members compared to the corresponding Swedish male population.

RESULTS

After 849 307 person-years of follow-up in 203 131 prostate cancer patients, there were 41 incident gallbladder cancers and 36 cancers of the extra-hepatic bile ducts. In overall, there were no apparent differences in the risk of gallbladder cancer or bile duct cancer between patients diagnosed in 1961-1980 and patients diagnosed in 1981-2008. However, in patients diagnosed in 1961-1980, there was a statistically non-significant increased risk of gallbladder cancer (SIR 1.34; 95% CI 0.71-2.29) and extra-hepatic bile duct cancer (SIR 1.20; 95% CI 0.55-2.28) > 5 years of follow-up after the prostate cancer diagnosis. No such association was found for patients diagnosed in 1981-2008. Sensitivity analyses excluding prostate cancer patients exposed to potential confounding factors did not change the SIRs.

CONCLUSIONS

Long exposure to high doses of exogenous estrogen might increase the risk of biliary tract cancer. However, any potential excess risk of bile duct cancer resulted by prolonged exposure to high doses of exogenous estrogen seems to be small.