(Results from the population-based PCBaSe Sweden)
Hormone therapy (ADT) is designed to prevent the manufacturing of testosterone however, testosterone is a very important preventive hormone, especially in the area of heart health. ADT also causes a number of metabolic side-effects including increased body weight, insulin resistance, dyslipidemia, and hyperglycemia. So, how is the risk of eliminating testosterone balanced against the risk of prostate cancer deaths?
Recently there has been a lot of investigation around the concerns of the increased risk of heart disease which is believed to be due to a reduced cardio-protective effect of testosterone.
A study I wish to report on focused on cardiovascular and thrombotic side effects following endocrine treatment (ADT) in the Swedish PCBaSe, which started in 1996 and captures more than 96% of all newly diagnosed, biopsy-confirmed prostate cancers.
The researchers analyzed the relation between different types of prostate cancer treatment and the following subtypes of cardiovascular disease in 76,600 prostate cancer patients (40% ADT, 35% curative treatment, and 25% surveillance): ischemic heart disease, acute myocardial infarction, arrhythmia, heart failure, and stroke, as well as the following subtypes of thrombotic disease: deep-venous thrombosis, pulmonary embolism, and arterial embolism.
They found that:
• the standardized incidence rates (SIRs) were elevated for each disease studied in all prostate cancer patients, with the highest SIR for those treated with ADT.
• These findings were independent of circulatory disease history (SIR for myocardial infarction in men without circulatory disease history: 1.40 (95%CI: 1.31-1.49), 1.15 (1.01-1.31), and 1.20 (1.11-1.30) for men on ET, curative treatment, and surveillance, respectively).
• In the study on thromboembolic diseases, the SIRs for men on ADT were increased for all thromboembolic diseases studies, especially deep-venous thrombosis and pulmonary embolism (2.48 (95%CI: 2.25-2.73) and 2.00 (1.81-2.22)).
• They also reported increased SIRs for curatively treated men and men on surveillance (eg. SIR for deep-venous thrombosis in curatively treated men 1.73 (1.47-2.01) and men on surveillance 1.27 (1.08-1.47)). Increased thromboembolic risks were maintained when stratified by different age and tumor stages strata.
• The absolute risk differences indicate that less than 10 extra cases of cardiovascular or thromboembolic disease per 1,000 person-years would occur after ADT.
The researchers concluded that based on the small absolute risk differences they saw and the high absolute risk of dying from metastatic prostate cancer and the fact that ADT is currently the only effective treatment for metastatic disease, these findings indicate that cardiovascular and thromboembolic risk should be considered when prescribing ADT, but not constitute a contraindication when the expected gain is tangible.
J Clin Oncol. 2010 Published online June 21. Mieke Van Hemelrijck, MSc, et al.
Joel T Nowak, M.A. M.S.W.