Medications with potential hormonal effects and cancer risk and survival

• Main Author: Karasneh, Reema Abdullah Ali
• Published: Queen's University Belfast 2017
• Subjects: 616.99
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.727410

This thesis aimed to examine the potential hormonal effects of medications on the risk of breast and upper gastrointestinal cancers including gastroesophageal, liver and pancreatic cancers and to examine whether their use after cancer diagnosis would influence survival in breast, colorectal, and prostate cancers. Different methodologies were used to achieve the aim of this thesis including systematic review and meta-analysis, population-based cohort studies, and nested case-control study. Utilising linked data sources from United Kingdom Clinical Practice Research Datalink, cancer registries, office of national statistics, and Scottish national datasets and Primary Care Clinical Informatics Unit Research Digoxin and spironolactone are phytoestrogens and in our systematic review and meta-analysis increased risk in breast cancer was observed with cardiac glycosides (mainly digoxin) use. Therefore, concerns have been raised about the safety of their use in breast cancer patients. Reassuringly, we found no evidence of reduced survival with digoxin/ spironolactone use in breast cancer patients. Similar findings were observed in colorectal cancer patients who used digoxin after diagnosis. Furthermore, despite the observed reductions in prostate cancer risk with digoxin use in several studies; we could not find any evidence of increased survival with digoxin use after prostate cancer diagnosis. Evidence from the literature suggests gender bias in upper gastrointestinal tract cancers suggesting a role for hormones and hormone receptors. The use of digoxin, hormone replacement therapy, and finasteride (an anti-androgen) and the risk of gastro-oesophageal, liver, and pancreatic cancers has been investigated in this thesis. There was an evidence of reduction in the risk of gastro-oesophageal cancer with HRT / finasteride use. These findings support that oestrogen may have anti-cancer effect on gastro-oesophageal cancer. The novel protective associations on gastro-oesophageal cancer with finasteride use require confirmation in large, observational studies before randomised controlled trials of finasteride use can be recommended.