The two most common types of cancer are breast and prostate cancers, with 10-year survival rates close to 80%. Some cancer patients may have pre-existing diseases that affect the heart and blood vessels: Cardiovascular diseases (CVD). Cancer and CVD share similar risk factors. Three of the most common pre-existing diseases in cancer patients are lipid disorders, heart diseases and diabetes. Drugs, such as lipid-lowering agents, are often recommended to treat these chronic diseases. In cancer patients with pre-existing CVD, it is estimated that only half receive drugs to treat their CVD after their cancer diagnosis. Receiving the best possible treatment for lipid disorders, high blood pressure and diabetes, is important as it affects the risk of serious CVD events, such as stroke.
We do not know whether the management strategy of CVD risk changes in breast- and prostate cancer survivors. Therefore, this study aims to find out whether patients who are prescribed diabetes drugs, and drugs to lower cholesterol and blood pressure levels continue using these drugs after a prostate or breast cancer diagnosis. We will also investigate to what extent the risk of serious CVD events in breast and prostate cancer survivors is affected by the use of these agents. To achieve this, we will compare the rate of serious CVD events in cancer survivors who continue to use diabetes drugs, cholesterol-lowering and blood pressure lowering drugs with similar patients who stopped their treatment temporarily. Our study will help to identify whether the treatment of cancer survivors with pre-existing CVD can be improved.
The number of people surviving cancer has increased substantially with the predicted 10-year survival rate as high as 84% for prostate cancer and 79% for breast cancer, respectively. It is common for cancer patients to have pre-existing conditions including cardiovascular disease or diabetes which may be attributed to similar causative risk factors.
Management of pre-existing conditions is essential in assuring the best possible outcomes for cancer patients. However, when patients undergo cancer treatment adherence to existing therapies is known to reduce.
Nonadherence to medications to prevent serious CVD events is associated with increased all-cause mortality, and greater risk of all-cause hospitalization. Adherence to drugs used for the primary prevention of CVD in cancer patients is especially important as some cancer treatments are associated with increase in risk of adverse CVD events due to their cardiotoxic properties. Furthermore, patients with pre-existing diseases may be more susceptible to side-effects of their cancer treatment or may not be able to use certain cancer treatments. This in turn, may affect further their long term survival.
This study therefore aims to 1) measure and compare the prescribing rates of lipid-lowering, antihypertensive, and antidiabetic agents before and after a breast or prostate cancer diagnosis and 2) to assess if continuation of cardiovascular treatment after a diagnosis of breast or prostate cancer lowers the risk of serious cardiovascular events. To achieve this, we will compare the rate of serious CVD events in cancer survivors who receive continued prescriptions for antihypertensives, antidiabetic and lipid-lowering agents with similar cancer survivors who receive intermittent treatment and measure. We will calculate an Incidence Rate Ratio (IRR) with a 95% confidence interval (CI) for the association between continuous CVD treatment after cancer diagnosis and serious CVD events using a propensity score weighted regression model.
An understanding of the impact of concomitant CVD prescribing during cancer care is pertinent in the development of strategies to improve adherence. This is particularly important considering the context of current NHS resource constraints, and the strategic direction towards limiting over-treatment/over-prescribing, especially if the gains are marginal.
Prescription rates of lipid-lowering, antiplatelet, antihypertensive and antidiabetic agents. –Serious
Cardiovascular events (non-fatal myocardial infarction, non-fatal stroke, and cardiovascular death)
Ruth Brauer - Chief Investigator - University College London ( UCL )
Ruth Brauer - Corresponding Applicant - University College London ( UCL )
Ian Wong - Collaborator - University College London ( UCL )
Kenneth Man - Collaborator - University College London ( UCL )
Li Wei - Collaborator - University College London ( UCL )
Pinkie Chambers - Collaborator - University College London ( UCL )
Wallis Lau - Collaborator - University College London ( UCL )
Yogini Jani - Collaborator - University College London ( UCL )
NCRAS Cancer Registration Data;NCRAS National Radiotherapy Dataset (RTDS) data;NCRAS Systemic Anti-Cancer Treatment (SACT) data;ONS Death Registration Data;Patient Level Index of Multiple Deprivation