New research uncovers how cancer therapies are escalating heart disease risk among older adults, spotlighting the need for better monitoring.

Study: Cardiovascular disease and stroke following cancer and cancer treatment in older adults. Image Credit: Tom Wanniwant / Shutterstock.com

A recent study published in the journal Cancer examines the risk of cardiovascular disease (CVD) in older adults who have undergone cancer treatment.

The challenges cancer survivors face after treatment

Recent advancements in cancer treatment have significantly improved survival rates and extended life expectancies of patients. However, cancer survivors are at a greater risk of future disease, including CVDs, related to either the cancer or its treatment as compared to the general population.

In fact, cancer patients are twice as likely to die of CVD. As a result, cancer patients, particularly those who have been prescribed cardiotoxic drugs, can be closely monitored to identify and manage their risk factors for CVD, alter treatment strategies, screen for heart abnormalities before and during treatment, and support physical exercise. Nevertheless, these monitoring strategies are not routinely incorporated into the healthcare plan for treating all cancer patients.

About the study

Data for the current study were acquired from the Aspirin in Reducing Events in the Elderly (ASPREE) trial to assess how cancer and cancer treatment impact a composite CVD endpoint in elderly cancer patients.

The ASPREE trial included 15,454 Australian and American patients with a median age of 74. Prostate and colorectal cancers affected 26% and 14% of study participants, respectively; breast and blood cancers affected 12% of the study cohort each, whereas lung and melanoma cancers affected 8% each.

Metastatic tumors were mostly from primary lung and prostate cancer, followed by CRC, pancreatic, and ovarian or uterine cancers. Over 80% of the study cohort received treatment, 55% of whom underwent surgery, 45% received chemotherapy, and 29% underwent radiation therapy.

Increased CVD risk

A total of 1,392 patients were newly diagnosed with cancer. As compared to cancer-free patients, cancer patients were twice as likely to be diagnosed with CVDs at 10.3 and 20.8 events for every 1,000 person-years, respectively.  

The cancer cohort had higher incidences of myocardial infarction (MI), hospitalization for heart failure (HHF), overall stroke, and ischemic stroke. This increased risk was unchanged after compensating for clinical risk factors for CVD.

A five-fold increased cancer incidence rate was observed among patients with metastatic cancer as compared to cancer-free individuals or those with localized cancer. Metastatic disease is more likely to be treated with higher doses or more cardiotoxic drugs, which contributes to the higher risk of CVDs, in addition to the increased severity associated with advanced cancer.

Among cancer types, hematologic and lung cancers were associated with a five- and three-fold increased risk of CVD, respectively. Importantly, lung cancer patients are more likely to be smokers, which confounds the CVD risk. However, this increased risk could also be related to the often delayed detection of lung and blood cancers.

For MI and HHF, the increased risk of CVDs was observed in the first year alone. Comparatively, when ischemic stroke was considered, the risk of developing CVDs increased more rapidly than in the cancer-free cohort from the third year onwards.

Among cancer patients, males were at a greater risk of CVDs after the first year as compared to women. Patients 75 years of age and older were also at an increased risk of CVDs that rose with time in both cancer and cancer-free cohorts.

Cancer chemotherapy was also associated with an increased risk of CVD by two-fold. This effect may be attributable to the cardiotoxicity of these drugs generally used for fitter patients.

Cancer patients who underwent surgery were at a reduced risk of developing CVD. In addition to these patients typically being reasonably fit at baseline, the rapid elimination of tumor-related factors may support the risk reduction. Comparatively, radiation therapy was associated with increased MI and HHF rates.

The use of aspirin did not appear to reduce CVD risk, as both aspirin and placebo groups exhibited similar incidence rates.

Conclusions

The study findings corroborate previous reports of a persistent increased risk of CVDs in older people after a cancer diagnosis; however, this risk weakens after five years. The highest risk of CVD was observed in patients with metastatic, hematologic, and lung cancers, as well as those who received chemotherapy.

Aspirin was ineffective in reducing CVD risk, which agrees with recent studies reporting the lack of a cardiovascular protective benefit observed in healthy older adults taking aspirin.

The clinical implications of our findings lie in the impact of CVD on mortality and the fact that with appropriate screening and management, cardiovascular risk in cancer survivors can be mitigated.”