Female reproductive factors, exogenous hormone use, and pancreatic cancer risk: the Japan Public Health Center-based prospective study

The Disproportionate Rise in Pancreatic Cancer in Younger Women Is Due to a Rise in Adenocarcinoma and Not Neuroendocrine Tumors: A Nationwide Time-Trend Analysis Using 2001-2018 United States Cancer Statistics Databases

In previous studies, a significant increase in the incidence of pancreatic cancer among younger women compared to men in the United States was noted. However, the specific histopathologic characteristics were not delineated. This population-based study aimed to assess whether this disproportionate rise in pancreatic cancer in younger women was contributed by pancreatic ductal adenocarcinoma (PDAC) or pancreatic neuroendocrine tumors (PanNET). The United States Cancer Statistics (USCS) database was used to identify patients with pancreatic cancer between 2001 and 2018. The results showed that, in younger adults, the incidence of PDAC has increased in women [average annual percentage change (AAPC) = 0.62%], while it has remained stable in men (AAPC = -0.09%). The PDAC incidence rate among women increased at a greater rate compared to men with a statistically significant difference in AAPC (p < 0.001), with neither identical nor parallel trends. In contrast, cases of PanNET did not demonstrate a statistically significant sex-specific AAPC difference. In conclusion, this study demonstrated that the dramatic increase in the incidence rate of PDAC explains the disproportionate rise in pancreatic cancer incidence in younger women. This prompts further prospective studies to investigate the underlying reasons for these sex-specific disparities in PDAC.

Adherence to the 2018 World Cancer Research Fund (WCRF)/American Institute for Cancer Research (AICR) Cancer Prevention Recommendations and risk of 14 lifestyle-related cancers in the UK Biobank prospective cohort study

BACKGROUND

The World Cancer Research Fund (WCRF)/American Institute for Cancer Research (AICR) Cancer Prevention Recommendations are lifestyle-based recommendations which aim to reduce cancer risk. This study investigated associations between adherence, assessed using a standardised scoring system, and the risk of all cancers combined and of 14 cancers for which there is strong evidence for links with aspects of lifestyle in the UK.

METHODS

We used data from 94,778 participants (53% female, mean age 56 years) from the UK Biobank. Total adherence scores (range 0-7 points) were derived from dietary, physical activity, and anthropometric data. Associations between total score and cancer risk (all cancers combined; and prostate, breast, colorectal, lung, uterine, liver, pancreatic, stomach, oesophageal, head and neck, ovarian, kidney, bladder, and gallbladder cancer) were investigated using Cox proportional hazard models, adjusting for age, sex, deprivation index, ethnicity, and smoking status.

RESULTS

Mean total score was 3.8 (SD 1.0) points. During a median follow-up of 8 years, 7296 individuals developed cancer. Total score was inversely associated with risk of all cancers combined (HR: 0.93; 95%CI: 0.90-0.95 per 1-point increment), as well as breast (HR: 0.90; 95%CI: 0.86-0.95), colorectal (HR: 0.90; 95%CI: 0.84-0.97), kidney (HR: 0.82; 95%CI: 0.72-0.94), oesophageal (HR: 0.84; 95%CI: 0.71-0.98), ovarian (HR: 0.76; 95%CI: 0.65-0.90), liver (HR: 0.78; 95%CI: 0.63-0.97), and gallbladder (HR: 0.70; 95%CI: 0.53-0.93) cancers.

CONCLUSIONS

Greater adherence to lifestyle-based recommendations was associated with reduced risk of all cancers combined and of breast, colorectal, kidney, oesophageal, ovarian, liver, and gallbladder cancers. Our findings support compliance with the Cancer Prevention Recommendations for cancer prevention in the UK.

Common variability in oestrogen-related genes and pancreatic ductal adenocarcinoma risk in women

The incidence of pancreatic ductal adenocarcinoma (PDAC) is different among males and females. This disparity cannot be fully explained by the difference in terms of exposure to known risk factors; therefore, the lower incidence in women could be attributed to sex-specific hormones. A two-phase association study was conducted in 12,387 female subjects (5436 PDAC cases and 6951 controls) to assess the effect on risk of developing PDAC of single nucleotide polymorphisms (SNPs) in 208 genes involved in oestrogen and pregnenolone biosynthesis and oestrogen-mediated signalling. In the discovery phase 14 polymorphisms showed a statistically significant association (P < 0.05). In the replication none of the findings were validated. In addition, a gene-based analysis was performed on the 208 selected genes. Four genes (NR5A2, MED1, NCOA2 and RUNX1) were associated with PDAC risk, but only NR5A2 showed an association (P = 4.08 × 10-5) below the Bonferroni-corrected threshold of statistical significance. In conclusion, despite differences in incidence between males and females, our study did not identify an effect of common polymorphisms in the oestrogen and pregnenolone pathways in relation to PDAC susceptibility. However, we validated the previously reported association between NR5A2 gene variants and PDAC risk.

Reproductive Factors, Use of Exogenous Hormones, and Pancreatic Cancer Incidence: The Norwegian Women and Cancer Study

Introduction

The incidence of pancreatic cancer is increasing worldwide and characterized by a particularly low survival rate. Studies have reported weak and inconsistent evidence for associations among reproductive factors, use of exogenous hormones, and pancreatic cancer incidence in women.

Purpose

To investigate relationships between reproductive factors, exogenous hormones, and the rate of pancreatic cancer incidence in a large population-based prospective cohort of women in Norway.

Methods

We used data from the Norwegian Women and Cancer study on 588 incident cases of pancreatic cancer diagnosed among 165,419 women, with mean follow-up of 18.7 years. Cox proportional-hazard models were used to estimate HRs and 95% CIs for associations of interest.

Results

Cumulative breastfeeding duration >24 months was associated with 63% decreased incidence of pancreatic cancer compared to no breastfeeding. We observed an inverse linear dose–response trend between cumulative breastfeeding duration and pancreatic cancer incidence, which was confirmed in parous women and ever-smokers. Higher age at first birth and menopause were inversely associated with pancreatic cancer incidence, though with less precise effect estimates. Current use of oral contraceptives was associated with a doubling of pancreatic cancer incidence, but the analysis was hampered by a small number of cases. There was no evidence of any associations between age at menarche, parity or use of menopausal hormone therapy, and incidence of pancreatic cancer.

Conclusion

Our results suggest a potential protective effect of breastfeeding duration against pancreatic cancer incidence. Inconsistent results for the other reproductive factors suggested no important role of estrogens in pancreatic cancer etiology.

Gynecological and reproductive factors and the risk of pancreatic cancer: A case-control study

BACKGROUND

/Objectives: Pancreatic ductal adenocarcinoma (PDAC) has a higher incidence in men compared to women, although the difference in known risk factors cannot explain this disparity completely. Reproductive and hormonal factors have been demonstrated in pre-clinical studies to influence pancreatic carcinogenesis, but the few published data on the topic are inconsistent. The aim was to investigate the role of reproductive and hormonal factors on PDAC occurrence in women.

METHODS

We conducted a unicenter case-control study; PDAC cases were matched to controls by age with a 1:2 ratio. Risk factors were screened through questionnaires about gynecologic and medical history. Comparisons were made using Chi-square and Fisher's exact tests where appropriate for categorical variables and Student's t-test for continuous variables. Logistic regression was used to calculate Odds Ratios (ORs) and their 95% confidence intervals (CI). Multivariable logistic regression models were adjusted for potential confounders.

RESULTS

253 PDAC and 506 matched controls were enrolled. At logistic regression multivariable analysis adjusted for confounding factors, older age at menopause (OR:0.95 per year; 95% CI:0.91-0.98; p = 0.007), use of Oral Contraceptives (OR:0.52; 95% CI:0.30-0.89; p = 0.018), use of Hormonal Replacement Therapy (OR:0.31; 95% CI:0.15-0.64; p = 0.001), and having had two children (OR:0.57; 95% CI:0.38-0.84; p = 0.005) were significant, independent protective factors for the onset of PDAC.

CONCLUSIONS

These data confirm some previous findings on menopause age and number of births while, to our knowledge, this is the first study to show a protective effect of HRT and OC use. The results collectively support the hypothesis that exposure to estrogens plays a protective role towards PDAC.