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Menopausal hormone therapy and risk of gastrointestinal cancer: Nested case–control study within a prospective cohort, and meta‐analysis
Author(s) -
Green Jane,
Czanner Gabriela,
Reeves Gillian,
Watson Joanna,
Wise Lesley,
Roddam Andrew,
Beral Valerie
Publication year - 2011
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.26236
Subject(s) - medicine , cancer , colorectal cancer , nested case control study , relative risk , prospective cohort study , cohort study , cohort , gastrointestinal cancer , confidence interval , gastroenterology , oncology , gynecology
Use of menopausal hormone therapy (HT) has been associated with reduced risk of colorectal cancer; evidence for its effect on other gastrointestinal cancers is limited. We conducted a nested case–control study within a UK cohort, and meta‐analyses combining our results with those from published studies. Our study included women aged 50+ in the UK General Practice Research Database (GPRD): 1,054 with oesophageal, 750 with gastric and 4,708 with colorectal cancer, and 5 age‐ and practice‐matched controls per case. Relative risks (RRs) and 95% confidence intervals (CIs) for cancer in relation to prospectively‐recorded HT prescriptions were estimated by conditional logistic regression. Women prescribed HT had a reduced risk of oesophageal cancer (adjusted RR for 1+ vs . no HT prescriptions, 0.68, 95% CI 0.53–0.88; p = 0.004), gastric cancer (0.75, 0.54–1.05; p = 0.1) and colorectal cancer (0.81, 0.73–0.90; p < 0.001). There were no significant differences in cancer risk by HT type, estimated duration of HT use or between past and current users. In meta‐analyses, risks for ever vs . never use of HT were significantly reduced for all three cancers (summary RR for oesophageal cancer, 0.68, 0.55–0.84, p < 0.001; for gastric cancer, 0.78, 0.65–0.94, p = 0.008; for colorectal cancer, 0.84, 0.81–0.88, p < 0.001). In high‐income countries, estimated incidence over 5 years of these three cancers combined in women aged 50–64 was 2.9/1,000 in HT users and 3.6/1,000 in never users. The absolute reduction in risk of these cancers in HT users is small compared to the HT‐associated increased risk of breast cancer.