Menstrual and reproductive factors and pancreatic cancer in the SEARCH program of the IARC

Association between residential exposure to petrochemical industrial complexes and pancreatic cancer: a systematic review and meta-analysis

Increased in the global demand-expansion of the petrochemical industry is a possible environmental risk factor pancreatic cancer among residents living close to petrochemical complexes. This meta-analysis aimed to estimate the pooled risk of pancreatic cancer among residents living near petrochemical industrial complexes. We systematically searched and reviewed published studies in six databases based on the inclusion criteria derived from the population, exposure, comparator, and outcomes framework (population: general population; exposure: residence near petrochemical industrial complexes/living in cities with petrochemical industrial complexes; comparators: residents living farther away from petrochemical industrial complexes/living in cities without petrochemical industrial complexes; outcome: pancreatic cancer). We identified seven studies, covering 1,605,568 residents. Pooled analysis showed a significantly higher risk of pancreatic cancer among residents living near petrochemical industrial complexes (relative risk [RR] = 1.31, 95% confidence interval [CI] = 1.21-1.42) than those living farther away from petrochemical industrial complexes. Such effect was higher in female residents (RR = 1.34, 95% CI = 1.18-1.53) than in male residents (RR = 1.26, 95% CI = 1.12-1.41). This study suggests that exposure to petrochemical industry-related activities should be recognized as a risk factor for pancreatic cancer among residents living near petrochemical industrial complexes.

Association between oral contraceptive use and pancreatic cancer risk: A systematic review and meta-analysis

BACKGROUND

Studies on the association of oral contraceptive (OC) use and pancreatic cancer showed inconsistent findings.

AIM

To evaluate the relationship between OC use and pancreatic cancer risk.

METHODS

A literature search for observational studies (case-control and cohort studies) was conducted up to December 2020. A meta-analysis was performed by calculating pooled relative risks (RRs) and 95% confidence intervals (CIs). Heterogeneity was assessed using Cochran’s chi-square test and I² statistic. Subgroup analyses were performed by study design, source of controls in case-control studies, number of cases of pancreatic cancers, study quality according to Newcastle-Ottawa Scale score, geographical region and menopausal status. All analyses were performed using Review Manager 5.3 (RevMan 5.3).

RESULTS

A total of 21 studies (10 case-control studies and 11 cohort studies) were finally included in the present meta-analysis, comprising 7700 cases of pancreatic cancer in total. A significant association was observed between the ever use of OC and pancreatic cancer risk in the overall analysis (RR = 0.85; 95%CI = 0.73-0.98; P = 0.03). Duration of OC use (< 1 year, < 5 years, 5-10 years, > 10 years) was not significantly associated with the risk of pancreatic cancer. Subgroup analyses revealed a statistically significant subgroup difference for the geographic region in which the study was conducted (Europe vs Americas vs Asia; P = 0.07). Subgroup analyses showed a statistically significant decrease in pancreatic cancer risk and OC use in high-quality studies, studies conducted in Europe, and in postmenopausal women.

CONCLUSION

Despite the suggested protective effects of OC use in this meta-analysis, further epidemiological studies are warranted to fully elucidate the association between the use of OC and pancreatic cancer risk.

Association of Sex Hormones with Risk of Cancers of the Pancreas, Kidney, and Brain in the UK Biobank Cohort Study

BACKGROUND

There is some evidence to suggest that endogenous levels of sex hormones might influence the etiology of cancers of the pancreas, kidney, and brain, but epidemiologic data are lacking.

METHODS

We evaluated the association of circulating levels of total and free testosterone, and of sex hormone-binding globulin (SHBG), with the risk of cancers of the pancreas, kidney, and brain, and of total and free estradiol with the risk of kidney cancer, in the UK Biobank cohort study (n = 425,793; 225 pancreatic cancers, 749 kidney cancers, 467 brain cancers). Multivariable Cox proportional hazards models were used to estimate HRs and 95% confidence intervals for the associations.

RESULTS

Testosterone and SHBG levels were not associated with risk of pancreatic cancer. Most of the associations for the other two anatomic sites were null. There were inverse associations between total testosterone and brain cancer in men and between SHBG and risk of kidney cancer in the total sample and in women. Estradiol was not associated with the risk of kidney cancer.

CONCLUSIONS

The results of this study provide little support for associations between sex hormones/SHBG and risk of cancers of the pancreas, kidney, and brain. Larger studies are warranted.

IMPACT

Although these results provide little support for roles for sex hormones and SHBG in the etiology of cancers of the pancreas, kidney, and brain, there is a need for studies with larger numbers of cases.

Hormonal contraceptive use and risk of pancreatic cancer-A cohort study among premenopausal women

IMPORTANCE

The association between the use of hormonal contraceptive and pancreatic cancer among premenopausal women has until now been unclear. This is the first study to investigate the risk of pancreatic cancer in pre-menopausal women.

OBJECTIVE

To determine whether hormonal contraception increases the risk of developing pancreatic cancer in pre-menopausal women.

DESIGN

A nationwide prospective cohort study followed all women in Denmark in the age range of 15-49 years without previous cancer or venous thrombosis from 1995 to 2014. The Danish National Prescription Registry provided individually updated exposure information on use of hormonal contraception. The Danish Cancer Registry provided cancer diagnoses, and the Danish National Patient Register containing clinical diagnoses and surgical codes at discharge from public and private hospitals.

SETTING

Population-based cohort study.

PARTICIPANTS

All women living in Denmark aged 15-49 years at January 1st, 1995, and those subsequently reaching age 15 years up to December 31st, 2014 were eligible for the study.

RESULTS

Among 1.9 million women who were followed on average for 11.4 years, 235 pancreatic cancers occurred. Compared to never users, ever users of any type of hormonal contraception had a relative risk (RR) of pancreatic cancer of 0.90 (95% confidence interval (CI) 0.68-1.19). No overall association between duration of hormonal contraceptive use and pancreatic cancer risk was found. Neither was long-term use of hormonal contraception associated with pancreas cancer, RR 0.83 (95% CI 0.47-1.50). The risk did not vary between users of combined and progestogen-only products. All models were adjusted for age, completed or ongoing education, polycystic ovary syndrome, endometriosis and among parous women; parity, age at first birth, smoking and body mass index.

CONCLUSIONS AND RELEVANCE

Compared to never users the risk of pancreatic cancer is not significantly higher among current and recent users of contemporary hormonal contraception and does not vary between users of combined and progestogen-only products. In conclusion, our study suggests no risk of pancreatic cancer with use of any type of hormonal contraception.

Hormonal factors and pancreatic cancer risk in women: The Malmö Diet and Cancer Study

The incidence of pancreatic cancer is leveling between sexes. Smoking, high age and heredity are established risk factors, but evidence regarding the influence of hormonal factors is unclear. In this study, we investigated the associations of reproductive factors, use of oral contraceptives (OC) and hormone replacement therapy (HRT) with pancreatic cancer risk in the Malmö Diet and Cancer Study, a prospective, population‐based cohort encompassing 17,035 women. Up until 31 December 2015, 110 women were identified with incident pancreatic cancer through the Swedish Cancer Registry. Higher age at menarche was significantly associated with pancreatic cancer risk (age‐adjusted [hazard ratio] HR = 1.17; 95% confidence interval [CI] 1.04–1.32, and fully adjusted HR = 1.17; 95% CI 1.04–1.32). Ever use of OC was not significantly associated with pancreatic cancer risk but ever use of HRT was significantly associated with a decreased risk of pancreatic cancer (age‐adjusted HR = 0.47, 95% CI 0.23–0.97, and fully adjusted HR = 0.48, 95% CI 0.23–1.00), in particular use of estrogen‐only regimen (age‐adjusted HR = 0.21; 95% CI 0.05–0.87 and fully adjusted HR = 0.22; 95% CI 0.05–0.90). Age at menopause or first childbirth, parity and breastfeeding history were not significantly associated with pancreatic cancer risk. Collectively, these findings suggest a protective role of female hormones against pancreatic cancer. Further studies are needed, and potential modifying genetic factors and indirect hazardous effects of smoking should also be considered.

What's new?

Female hormones appear to protect against pancreatic cancer, at least in Sweden. Numerous studies have investigated the relationship between the two, but no clear picture has yet emerged. These authors used data from the Malmö Diet and Cancer study, looking for correlations between hormone levels and cancer risk. They found that a younger start to menstruation—indicating an earlier boost in estrogen—correlated with less chance of developing pancreatic cancer. Use of hormone replacement therapy, particularly estrogen‐only therapy, significantly reduced risk among postmenopausal women. Breastfeeding, oral contraceptive use and parity did not appear to affect pancreatic cancer risk.

Reproductive factors, exogenous hormone use, and risk of pancreatic cancer in postmenopausal women

INTRODUCTION

The epidemiologic literature on menstrual and reproductive factors associated with pancreatic cancer has yielded weak and inconsistent evidence of an association. Furthermore, few cohort studies have examined the association of exogenous hormone use, including type and duration, with this disease. The aim of this study was to assess the association of these exposures with risk of pancreatic cancer in a large cohort of postmenopausal women.

METHODS

We used data from the Women's Health Initiative on 1003 cases of pancreatic cancer diagnosed among 158,298 participants over 14.3 years of follow-up. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (95% CI) for the associations of interest.

RESULTS

Being parous vs. nulliparous was associated with reduced risk (HR=0.84, 95% CI 0.70-1.00), and women who had 1-2 and 3-4 births were at decreased risk compared to nulliparous women, whereas women who had >5 births showed no decrease in risk. Compared to women who gave birth between the ages of 20-29, women who gave birth at age 30 or above were at increased risk (HR 1.23, 95% CI 1.00-1.53, p for trend 0.003). Other reproductive factors and exogenous hormone use were not associated with risk.

CONCLUSIONS

Together with the existing literature on this topic, our results suggest that reproductive and hormonal exposures are unlikely to play an important role in the etiology of pancreatic cancer.

Menstrual and Reproductive Factors, Hormone Use, and Risk of Pancreatic Cancer: Analysis From the International Pancreatic Cancer Case-Control Consortium (PanC4)

OBJECTIVES

We aimed to evaluate the relation between menstrual and reproductive factors, exogenous hormones, and risk of pancreatic cancer (PC).

METHODS

Eleven case-control studies within the International Pancreatic Cancer Case-control Consortium took part in the present study, including in total 2838 case and 4748 control women. Pooled estimates of odds ratios (ORs) and their 95% confidence intervals (CIs) were calculated using a 2-step logistic regression model and adjusting for relevant covariates.

RESULTS

An inverse OR was observed in women who reported having had hysterectomy (ORyesvs.no, 0.78; 95% CI, 0.67-0.91), remaining significant in postmenopausal women and never-smoking women, adjusted for potential PC confounders. A mutually adjusted model with the joint effect for hormone replacement therapy (HRT) and hysterectomy showed significant inverse associations with PC in women who reported having had hysterectomy with HRT use (OR, 0.64; 95% CI, 0.48-0.84).

CONCLUSIONS

Our large pooled analysis suggests that women who have had a hysterectomy may have reduced risk of PC. However, we cannot rule out that the reduced risk could be due to factors or indications for having had a hysterectomy. Further investigation of risk according to HRT use and reason for hysterectomy may be necessary.

Modifiable and non-modifiable risk factors for pancreatic cancer: A review

Pancreatic ductal adenocarcinoma is associated with a poor prognosis and a high case-fatality rate. The reasons for poor prognosis are low rates of curative resection due to local infiltration and distant metastasis. To increase survival rates of patients with pancreatic cancer, early detection through surveillance and screening is important. However, screening could only be cost-effective in high-risk populations. Identification of significant risk factors therefore assumes significance. Risk factors could be non-modifiable or modifiable. Non-modifiable risk factors include increasing age, familial cancer syndromes, Afro-American race, hereditary and other forms of chronic pancreatitis, diabetes, and non-O blood group. Important modifiable risk factors include smoking, obesity, dietary factors such as non-vegetarian diet, and toxins. Preventive strategies at the population level and an effective screening program targeted at high-risk people may help in prevention and early detection of pancreatic ductal adenocarcinoma.

Relationship between female hormonal and menstrual factors and pancreatic cancer: a meta-analysis of observational studies

The objective of this study was to assess the relationship between female hormone and menstrual factors and pancreatic cancer (PC) through a meta-analysis of observational studies. We undertook a systematic literature search up to July 10, 2014 in PubMed and EMBASE databases. Combined relative risks (RRs) were estimated by random-effects models. Subgroup analysis was performed by study design, source of control, and geographic regions. Sensitivity analyses and publication bias were utilized to evaluate the robustness of our results. A total of 27 case-control and cohort studies were retrieved for this meta-analysis. No significant associations were observed between the risk of PC and age at menarche (RR = 0.94, 95% confidence interval [CI] 0.83-1.07), age at menopause (RR = 0.98, 95% CI 0.85-1.13), hysterectomy (RR = 0.97, 95% CI 0.84-1.11), oophorectomy (RR = 1.02, 95% CI 0.82-1.26), hormone replacement therapy (RR = 0.97, 95% CI 0.87-1.08), and oral contraceptives (RR = 1.09, 95% CI 0.96-1.23). This meta-analysis of observational studies does not support the hypothesis that exogenous hormone use and menstrual factors are associated with PC.

Parity and pancreatic cancer risk: evidence from a meta-analysis of twenty epidemiologic studies

Multiple studies have hypothesized parity is associated with pancreatic cancer risk but obtained conflicting results. We conducted a meta-analysis (including a dose-response approach) of current available epidemiologic studies to investigate the association between parity and risk of pancreatic cancer. Ten cohort studies and ten case-control studies including 8205 cases were eligible for inclusion. The combined RR (relative risk) of pancreatic cancer for the parous vs. nulliparous was 0.91 (95% CI, confidence interval = 0.85–0.97, I² = 39.0%, P_h = 0.01). We observed an inverse association between giving birth to two children pancreatic cancer risk with RR of 0.86 (95% CI = 0.80–0.93, I² = 8.7%, P_h = 0.36). And no evidence supported there was non-linear (P = 0.33) or linear relationship (P = 0.14) between number of parity and risk of pancreatic cancer. Findings from this meta-analysis indicate that giving birth to two children has the lowest pancreatic cancer risk, mechanism of this protective effect needs further investigation.

Parity and pancreatic cancer risk: a dose-response meta-analysis of epidemiologic studies

Background

Previous epidemiologic studies have reported inconsistent results between parity and pancreatic cancer (PC) risk. To our knowledge, a comprehensive and quantitative assessment of this association has not been conducted.

Methods

Relevant published studies of parity and PC were identified using MEDLINE (PubMed) and Web of Science databases until November 2013. Two authors (H-BG and LW) independently assessed eligibility and extracted data. Eleven prospective and 11 case-control studies reported relative risk (RR) estimates and 95% confidence intervals (CIs) of PC associated with parity. Fixed- and random-effects models were used to estimate the summary RR depending on the heterogeneity of effects.

Results

The summary RR for PC comparing the highest versus lowest parity was 0.86 (95% CI: 0.73–1.02; Q = 50.49, P<0.001, I² = 58.4%). Significant inverse associations were also observed in the studies that adjusted for cigarette smoking (RR = 0.81; 95% CI: 0.68–0.98), Type 2 diabetes mellitus (RR = 0.83; 95% CI: 0.75–0.93), and those that included all confounders or important risk factors (RR = 0.85; 95% CI: 0.76–0.96). Additionally, in the dose-response analysis, the summary RR for per one live birth was 0.97 (95% CI: 0.94–1.01; Q = 62.83, P<0.001, I² = 69.8%), which also indicated a borderline statistically significant inverse effect of parity on PC risk. No evidence of publication bias and significant heterogeneity between subgroups were detected by meta-regression analyses.

Conclusion

In summary, these findings suggest that higher parity is associated with a decreased risk of PC. Future large consortia or pooled studies are warranted to fully adjust for potential confounders to confirm this association.

Reproductive factors, exogenous hormones, and pancreatic cancer risk in the CTS

Female steroid hormones are hypothesized to play a protective role in pancreatic cancer risk. However, results from epidemiologic studies that examined hormone-related exposures have been inconsistent. The California Teachers Study is a cohort study of female public school professionals that was established in 1995-1996. Of the 118,164 eligible study participants, 323 women were diagnosed with incident invasive pancreatic cancer through December 31, 2009. Multivariable Cox proportional hazards regression methods were used to estimate hazard ratios and 95% confidence intervals for the association of pancreatic cancer risk with reproductive factors and exogenous hormone use. Current users of estrogen-only therapy at baseline (1995-1996) had a lower risk of pancreatic cancer than did participants who had never used hormone therapy (hazard ratio = 0.59, 95% confidence interval: 0.42, 0.84). Use of estrogen-plus-progestin therapy was not associated with the risk of pancreatic cancer. A longer duration of oral contraceptive use (≥10 years of use compared with never use) was associated with an increased risk of cancer (hazard ratio = 1.72, 95% confidence interval: 1.19, 2.49). Reproductive factors, including age at menarche, parity, breastfeeding, and age at menopause, were not associated with pancreatic cancer risk. Our results suggest that increased estrogen exposure through estrogen-only therapy may reduce pancreatic cancer risk in women.

Menstrual and reproductive factors in women, genetic variation in CYP17A1, and pancreatic cancer risk in the European prospective investigation into cancer and nutrition (EPIC) cohort

Menstrual and reproductive factors and exogenous hormone use have been investigated as pancreatic cancer risk factors in case-control and cohort studies, but results have been inconsistent. We conducted a prospective examination of menstrual and reproductive factors, exogenous hormone use and pancreatic cancer risk (based on 304 cases) in 328,610 women from the EPIC cohort. Then, in a case-control study nested within the EPIC cohort, we examined 12 single nucleotide polymorphisms (SNPs) in CYP17A1 (an essential gene in sex steroid metabolism) for association with pancreatic cancer in women and men (324 cases and 353 controls). Of all factors analyzed, only younger age at menarche (<12 vs. 13 years) was moderately associated with an increased risk of pancreatic cancer in the full cohort; however, this result was marginally significant (HR = 1.44; 95% CI = 0.99-2.10). CYP17A1 rs619824 was associated with HRT use (p value = 0.037) in control women; however, none of the SNPs alone, in combination, or as haplotypes were associated with pancreatic cancer risk. In conclusion, with the possible exception of an early age of menarche, none of the menstrual and reproductive factors, and none of the 12 common genetic variants we evaluated at the CYP17A1 locus makes a substantial contribution to pancreatic cancer susceptibility in the EPIC cohort.

Reproductive and hormonal factors and pancreatic cancer risk in women

OBJECTIVES

To investigate the role of menstrual, reproductive, and hormonal factors, as well as benign female conditions, on pancreatic cancer risk.

METHODS

We analyzed the combined data from 2 Italian case-control studies including 285 female case patients of pancreatic cancer and 713 female controls. All subjects were interviewed by trained interviewers during their hospital stay using similar structured questionnaires. Odds ratios (ORs) and their corresponding 95% confidence intervals (CIs) were estimated using multiple logistic regression models adjusted for selected covariates.

RESULTS

Compared to nulliparae, the OR was 0.76 (95% CI, 0.51-1.12) for parous women and 0.46 (95% CI, 0.26-0.85) for women with 4 or more births, in the absence, however, of a significant trend with increasing number of births. Pancreatic cancer risk was also nonsignificantly reduced among women with age at first birth lower than 25 years (OR, 0.65; 95% CI, 0.42-1.01). Other factors, including age at menarche and menopause, menopausal status, type of menopause, history of spontaneous and induced abortions, use of oral contraceptives and hormone replacement therapy, and history of most female benign conditions were not related to pancreatic cancer risk.

CONCLUSIONS

This study provides little support for the hypothesis that menstrual, reproductive, or hormonal factors are related to the development of pancreatic cancer.