Adult cancer survivors at high risk for cardiovascular disease
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A growing body of evidence suggests cancer survivors face elevated risk for cardiovascular disease years after diagnosis.
Now, findings from analysis of data on about 12,000 people followed over decades have strengthened the evidence indicating a strong link between cancer survival and cardiovascular disease (CVD), particularly heart failure.
“Patients diagnosed with cancer are living longer and, in many cases, dying from other conditions such as cardiovascular disease,” Roberta Florido, MD, MHS, director of cardio-oncology at Johns Hopkins Medicine in Baltimore, said in an interview with Healio. “There has been increasing attention to the links between cancer and cardiovascular disease, but up until now the data on the risk of cardiovascular disease in cancer survivors had been limited. We leveraged data from a community-based cohort of U.S. participants who have been followed over decades with detailed information on cancer, cardiovascular disease and risk factors to assess the risk for cardiovascular disease and cardiovascular disease subtypes in survivors of various cancers. We found that, overall, cancer survivors have a 42% higher risk of cardiovascular disease compared with persons without prior cancer and 59% higher risk of future heart failure.”
Florido spoke with Healio about the possible drivers of the increased risk for CVD, the differences in risk across cancer types, and the need for further research in this area.
Healio: What was unique about the population in your study?
Florido: Our large, diverse, community-based cohort study included men and women with long-term follow-up. Furthermore, we benefited from information on cancer and cardiovascular disease events over decades of participant follow up, as well as very detailed information on cardiovascular risk factors (eg, smoking, high blood pressure, diabetes, obesity). All the information available in this study allowed us to accurately assess the risk for cardiovascular disease and cardiovascular disease subtypes in cancer survivors. It also allowed us to assess if the increased cardiovascular risk in cancer survivors is all due to traditional cardiovascular risk factors, such as smoking and diabetes.
Healio: What did you find?
Florido: We found that cancer survivors had a 42% greater risk for future cardiovascular disease than persons without prior cancer. We then evaluated specific types of heart disease and found that cancer survivors had significantly higher risk for heart failure (59% higher than persons without prior cancer) and a modestly increased risk for stroke (24% higher than persons without prior cancer). Importantly, this risk remained elevated even after we accounted for differences in risk factors such as smoking, obesity, hypertension and diabetes between the two groups. What that suggests is the increased risk for CVD among cancer survivors is not entirely caused by these risk factors and that there may be something unique in this population causing CVD. We can’t be sure what is driving the increased risk for CVD in cancer survivors, but we have some hypotheses. For example, we know some cancer therapies can negatively affect the heart function and it is possible that in the long term, they increase risk for heart failure.
Healio: What types of cancers were associated with an increased risk for CVD and why?
Florido: In our study we were able to assess the risk for CVD in survivors of the most common cancers. We found survivors of different cancers had variable risks for CVD. For example, survivors of hematologic malignancies such as leukemias and lymphomas had a 2.6-fold higher risk for CVD and 3-fold higher risk for heart failure than persons without prior cancer. They also had a 74% higher risk for coronary heart disease and 58% higher risk for stroke than persons without prior cancer. Conversely, survivors of prostate cancer had similar risk for CVD as persons without prior cancer. Although we are not certain, such variability in the excess risk for CVD among survivors of various cancers suggests cancer treatments may play a role. For example, leukemias and lymphomas are often treated with chemotherapy, including drugs that have the potential of harming the heart. Many of these patients also get chest radiation, which can increase the risk of valve disease, heart failure and coronary artery disease many years after treatment. Prostate cancer on the other hand is often very indolent and may be managed with observation or less aggressive therapies.
Healio: How long after active cancer treatment did CVD develop?
Florido: The median follow-up time to CVD for patients who did not have cancer was 14 years. For the patients with cancer, the average time from the date of cancer diagnosis to CVD diagnosis was 5 years, but this varied by type of cancer. This variation could be related to the therapies they received — some may cause more acute toxicities, and others may increase risk in the long term. Lifestyle factors may also be relevant — for example, many patients with lung cancer may smoke heavily, causing premature CVD.
Healio: What are the implications of your study? What improvements are needed?
Florido: The most important take-home point is that cancer survivors have significantly higher risk for CVD and may benefit from aggressive cardiovascular risk factor modification and prevention. Despite this growing evidence showing a strong link between cancer and cardiovascular disease, CVD screening and prevention practices among cancer survivors are highly variable and often neglected. Cancer survivors may have routine surveillance for cancer recurrence, but little attention is given to their cardiovascular health. This is likely due to limited evidence guiding screening and prevention of CVD in cancer survivors, as well as misconceptions regarding competing risks for cancer mortality. Both the oncology community and primary care providers need to be aware that there is higher risk for CVD in this population and manage their cardiovascular risk factors accordingly. When more specialized care is needed, patients should be referred to a cardiologist, ideally someone with expertise in cardio-oncology. This study also shows gaps in our knowledge and a need for further study. For example, we need to better understand the potential toxicities of all cancer treatments and how much of the excess risk for CVD in cancer survivors can be attributed to these.
Healio: What future research do you have planned in this area?
Florido: We want to understand what exactly is driving this risk so we can develop better ways to predict the risk and prevent CVD in cancer survivors.
For more information:
Roberta Florido, MD, MHS, can be reached at Johns Hopkins University, 600 N. Wolfe St., Baltimore, MD 21287; email: rflorid1@jhmi.edu.
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