Montreal—When cancer patients took statins after radiation therapy of the chest, neck, or head, their risk of stroke—and maybe other cardiovascular complications—plummeted by nearly a third, according to a new study.
The study reported in the Journal of the American Heart Association was touted as the first to look at whether statins reduce cardiovascular complications in certain cancer patients.
The research, led by McGill University Health Center, is especially significant because more than half of cancer patients are treated with radiation therapy. Cardiovascular disease is the leading cause of illness and death among cancer survivors, according to background information in the report, at least partly because radiation-therapy side effects include scarring or thickening of arteries. In some cases, that results in blockages that can lead to myocardial infarction and stroke.
The study team sought to determine whether the cholesterol-lowering drugs also reduced vascular complications in thorax, head, and neck cancer patients postradiotherapy.
To do that, Canadian researchers conducted a retrospective cohort study within a provincial linked database of 5,718 cardiac patients with thorax and head or neck cancer who had undergone radiotherapy between 2000 and 2011. The study involved 1,552 nonstatin users and 4,166 statin users.
Defined as the primary outcome of interest was the composite of cerebrovascular events—transient ischemic attack and fatal or nonfatal stroke—or cardiovascular events—fatal or nonfatal myocardial infarction.
The study calculated that the crude event rate was 10.31% for nonusers and 9.03% for statin users (HR 0.92; 95% CI, 0.76-1.10; P = .3451), over a mean time to event/censoring of 534±687 days for nonusers and 594±706 days for the statin users.
Study authors said they adjusted those crude findings for age, sex, prior history of stroke/transient ischemic attack or myocardial infarction, diabetes mellitus, dyslipidemia, atrial fibrillation, chronic kidney disease, heart failure, and hypertension, determining at that point that statin use postradiotherapy was associated with a nonsignificant 15% relative risk reduction.
On the other hand, they found a strong trend toward reducing the primary outcome (HR 0.85; 95% CI, 0.69-1.04, P = .0811), and emphasized that the use of statins was associated with a significant reduction of 32% for the outcome of stroke alone (HR 0.68; 95% CI, 0.48-0.98, P = .0368).
“Statin use post radiation therapy was associated with a significant reduction in stroke, with a trend toward significantly reducing cardiovascular and cerebrovascular events,” the authors concluded.
Researchers called for prospective randomized controlled trials to definitively establish the benefit of statins in this at-risk population and to define guidelines on the management of radiation-induced vascular disease.
“Statins decrease cholesterol levels and have anti-inflammatory properties. Multiple studies have revealed the beneficial effects of statin therapy on reducing the risks of vascular disease in a variety of populations,” explained study coauthor Negar Mousavi, MD, MHSc. “Statins are protective in patients with heart disease, previous strokes and with high cholesterol levels.”
“Our study demonstrated that statin therapy could be favorable even with the competing risks of cancer and cancer-related mortality in patients who received radiation therapy,” Mousavi added, noting, “No other agent is recommended with enough evidence to reduce the risk of vascular events among cancer patients receiving radiation to the head, neck or chest.”
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The study reported in the Journal of the American Heart Association was touted as the first to look at whether statins reduce cardiovascular complications in certain cancer patients.
The research, led by McGill University Health Center, is especially significant because more than half of cancer patients are treated with radiation therapy. Cardiovascular disease is the leading cause of illness and death among cancer survivors, according to background information in the report, at least partly because radiation-therapy side effects include scarring or thickening of arteries. In some cases, that results in blockages that can lead to myocardial infarction and stroke.
The study team sought to determine whether the cholesterol-lowering drugs also reduced vascular complications in thorax, head, and neck cancer patients postradiotherapy.
To do that, Canadian researchers conducted a retrospective cohort study within a provincial linked database of 5,718 cardiac patients with thorax and head or neck cancer who had undergone radiotherapy between 2000 and 2011. The study involved 1,552 nonstatin users and 4,166 statin users.
Defined as the primary outcome of interest was the composite of cerebrovascular events—transient ischemic attack and fatal or nonfatal stroke—or cardiovascular events—fatal or nonfatal myocardial infarction.
The study calculated that the crude event rate was 10.31% for nonusers and 9.03% for statin users (HR 0.92; 95% CI, 0.76-1.10; P = .3451), over a mean time to event/censoring of 534±687 days for nonusers and 594±706 days for the statin users.
Study authors said they adjusted those crude findings for age, sex, prior history of stroke/transient ischemic attack or myocardial infarction, diabetes mellitus, dyslipidemia, atrial fibrillation, chronic kidney disease, heart failure, and hypertension, determining at that point that statin use postradiotherapy was associated with a nonsignificant 15% relative risk reduction.
On the other hand, they found a strong trend toward reducing the primary outcome (HR 0.85; 95% CI, 0.69-1.04, P = .0811), and emphasized that the use of statins was associated with a significant reduction of 32% for the outcome of stroke alone (HR 0.68; 95% CI, 0.48-0.98, P = .0368).
“Statin use post radiation therapy was associated with a significant reduction in stroke, with a trend toward significantly reducing cardiovascular and cerebrovascular events,” the authors concluded.
Researchers called for prospective randomized controlled trials to definitively establish the benefit of statins in this at-risk population and to define guidelines on the management of radiation-induced vascular disease.
“Statins decrease cholesterol levels and have anti-inflammatory properties. Multiple studies have revealed the beneficial effects of statin therapy on reducing the risks of vascular disease in a variety of populations,” explained study coauthor Negar Mousavi, MD, MHSc. “Statins are protective in patients with heart disease, previous strokes and with high cholesterol levels.”
“Our study demonstrated that statin therapy could be favorable even with the competing risks of cancer and cancer-related mortality in patients who received radiation therapy,” Mousavi added, noting, “No other agent is recommended with enough evidence to reduce the risk of vascular events among cancer patients receiving radiation to the head, neck or chest.”
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