On the crossroads of cardiovascular disease and cancer: shared risk factors and treatment strategies

Although cardiovascular-related mortality has decreased in the past decades, the number of patients in a chronic phase of cardiovascular disease is still growing. Cardiovascular disease shares several important modifiable risk factors with cancer, including smoking and obesity. Given these shared risk factors, patients with vascular disease might not only be at increased risk of recurrent vascular events, but also of cancer. Knowledge about the risk of cancer and specific causes of death in these patients, as well as a better understanding of important risk factors, may yield treatment strategies that could simultaneously reduce the burden of these diseases. In this thesis it is shown that patients with vascular disease have a 19% higher risk of developing cancer compared to the general population. Furthermore, patients with vascular disease die 5.5 years younger on average than the general population, with 80% of the excess years of life lost attributable to cardiovascular disease. Middle-aged patients lose an excess ten years of potential life, of which 24% are lost due to cancer. Adherence to treatment goals for secondary cardiovascular prevention, including smoking cessation, weight management, physical activity, diabetes management and antithrombotics could potentially reduce the risk of cancer in patients with vascular disease. In this thesis it is shown that the risk of cancer in patients who met all treatment goals was 30% lower than in those meeting only 0 to 2 goals. This thesis also focuses on the translation of results from clinical trials to individual patients. Rather than determining the efficacy of a specific treatment based on a group-level average treatment effect, the treatment effects for individual patients are predicted using a multivariable prognostic model including clinically available patient characteristics. Such individualized prediction of treatment effects provides a comprehensive approach to identify those patients who benefit most from treatment, enabling clinicians to make patient-tailored treatment decisions and better weigh treatment benefits against harms. This method is demonstrated for alternate-day aspirin in women for the primary prevention of cardiovascular disease and cancer as well as for pemetrexed plus carboplatin versus single-agent pemetrexed as second-line chemotherapy in advanced non-squamous non-small cell lung cancer. In both cardiovascular medicine and oncology the approach of individualized treatment effect prediction could be used to guide clinical decision-making to improve clinical outcome and to select patients for randomized trials.