Early Cardiovascular Death in Patients with Cancer

Abstract

To the Editor: The increased risk of cardiovas-cular death in the weeks after a diagnosis of can-cer has been described in several recent arti-cles. 1,2 Each one cites the psychological stress of receiving a diagnosis of cancer as a potential ex-planation for this risk. We believe that a major and underreported confounder is the risk of car-diovascular death that accompanies surgical pro-cedures that are therapeutic, diagnostic, or both in these patients. Surgery and general anesthesia are associated with a risk of cardiovascular illness and death in the initial postoperative period. 3 Rates of cardiac death or nonfatal myocardial infarction range from less than 1% among patients who have un-dergone low-risk surgery to 5% or less among patients who have undergone intermediate-risk surgery to even higher rates among patients who have undergone high-risk surgery. To examine surgery as a major confounder (or maybe even cause) of cardiovascular death after a diagnosis of cancer, we conducted an analysis in-volving all 287,512 patients who received a diagno-sis of cancer between 1998 and 2008 in the Sur-veillance, Epidemiology, and End Results (SEER) registry and who died within 1 month after diagnosis. We examined the proportion of cardiovascu-lar deaths in the 32,990 patients who had sur-gery to the primary site as compared with the 173,965 patients who did not have surgery. A total of 80,557 patients in whom data on surgery were unknown were excluded. Using a chi-square test, we found that cardiovascular death was significantly more common in patients who un-derwent surgery for the primary tumor than in those who did not have surgery (12.3% vs. 5.5%, P<0.001) (Fig. 1). Limitations to this analysis include other potential confounders that could not be analyzed with the use of data from the SEER registry; these confounders include coex-isting medical conditions, performance status, and cardiovascular risk factors. However, it is known that patients with cancer who have clini-cally significant coexisting conditions are less likely to undergo surgery for cancer. 4,5 These data suggest that patients who under-went surgery after a cancer diagnosis were more than twice as likely to die from a cardiac cause within the first month than those who did not undergo surgery. This proportion appears simi-lar to the increased risk among patients with cancer that was previously attributed to the psy-chological stress of a cancer diagnosis. We think that in the future, investigators reporting car-diovascular death in patients with a recent diag-nosis of cancer should report the rates of sur-gery, since it probably has an effect on the rates of early cardiovascular deaths among these pa-tients, possibly over and above any influence of psychological stress.