Association between ischaemic bowel syndromes and androgen deprivation therapy in patients with prostate cancer: a retrospective cohort study

OBJECTIVE: This study investigated the risk of ischaemic bowel syndrome (IBS) in androgen deprivation therapy (ADT) users to explore the long-term outcomes of patients with prostate cancer (PC) receiving ADT treatment. METHODS: We performed a population-based retrospective cohort study. All the clinical information of the study participants were acquired from the Longitudinal Health Insurance Database for Catastrophic Illness Patients in Taiwan. We extracted data for all the patients newly diagnosed with prostate malignancy (ICD-9-CM 185 or C61 in ICD-10-CM) from 2000 to 2008. The patients were then divided into two groups: 7160 male ADT cohort receiving ADT and 7160 male non-ADT comparison group frequency matched by age and index year of ADT treatment of the ADT group. Cox proportional hazard regression was used to estimate the adjusted HR and 95% CIs of the IBS risk. RESULTS: No significant difference was noted in the overall incidence rate for IBS between the ADT and non-ADT cohorts (0.86 and 0.89 per 1000 person–year, respectively, p=0.89). Even after adjusting for potential risk factors, a 1.06-fold risk of IBS (95% CI 0.62 to 1.82, p=0.82) was observed in the ADT cohort relative to the non-ADT cohorts. Moreover, we stratified the ADT cohort by time point of ADT treatment after PC diagnosis. Different IBS incidence rates were observed among the early ADT, late-ADT and non-ADT users at 0.77, 1.23 and 0.89 per 1000 person-years, respectively; nonetheless, the difference was not statistically significant. Moreover, no difference was found between the ADT treatment types and IBS risk, including sole orchiectomy, sole luteinising-hormone-releasing hormone and both. CONCLUSIONS: Results showed that ADT treatment in patients with PC is not an independent factor for IBS incidence. Large sample sizes for patients with IBS with patients with PC who had received ADT treatment are needed for further study.