Fatal heart disease among cancer patients

Abstract

As the overlap between heart disease and cancer patients increases as cancer-specific mortality is decreasing and the surviving population is aging, it is necessary to identify cancer patients who are at an increased risk of death from heart disease. The purpose of this study is to identify cancer patients at highest risk of fatal heart disease compared to the general population and other cancer patients at risk of death during the study time period. Here we report that 394,849 of the 7,529,481 cancer patients studied died of heart disease. The heart disease-specific mortality rate is 10.61/10,000-person years, and the standardized mortality ratio (SMR) of fatal heart disease is 2.24 (95% CI: 2.23-2.25). Compared to other cancer patients, patients who are older, male, African American, and unmarried are at a greatest risk of fatal heart disease. For almost all cancer survivors, the risk of fatal heart disease increases with time.

Fig. 1. Standardized mortality ratios (SMRs) of fatal heart disease among cancer patients by cancer subsite.

The y-axis depicts the SMR with 95% CI, and the x-axis depicts the disease site. Different time periods after diagnosis (<1 year vs 1–5 years vs 5–10 years vs >10 years) are shown in blue, orange, grey, and yellow, respectively. At the 1–5 year post-diagnosis time point, the risk of heart disease among cancer patients is two times that of the general population and rises with longer follow-up time. Certain cancer patients have relatively high SMR from heart disease in the first year after diagnosis (e.g. lung with SMR of 13.3, and myeloma with SMR of 7.5). These 12 cancer were chosen as they represent the sites with the greatest number of person–years at risk. Total person years at risk = 1,195,381.08. Error bars represent the 95% CI by site. Source data are provided as a Source Data file.

Fig. 2. Age adjusted mortality rates per 100,000 for fatal heart disease by cancer subsite.

a The y-axis depicts the heart disease-specific mortality rate per 100,000 and the x-axis depicts the age group at diagnosis in years. The colors depict the disease sites as follows: light blue = prostate; dark blue = colon and rectum; pink = breast; white = lung; yellow = bladder; black = melanoma; green = non-Hodgkin lymphoma; orange = kidney; light orange = leukemia; gray = oral cavity and pharynx; coral = endometrial; maroon = myeloma; purple = Hodgkin lymphoma; dark pink = testicular. The plurality of fatal heart disease occurs in patients diagnosed with cancer of the prostate, colon and rectum, breast, and lung, and the majority fatal heart disease cases are diagnosed at an older age. b The y-axis depicts the relative heart disease-specific mortality rate per 100,000 compared to all cancer patients, and the x-axis depicts the age group at time of diagnosis. For each age group, heart disease-specific mortality rates are displayed as a relative percentage to other cancer sites in that specific age group. The colors depict the disease sites. For patients under age 40, the plurality of heart disease deaths occurs in patients treated for breast cancer and lymphomas. In contrast, among patients ≥40 years old, the plurality of heart disease deaths occurs in patients treated for cancers of the prostate, breast, and colon and rectum. Source data are provided as a Source Data file.

Fig. 3. Observed number of deaths due to primary cancer vs. fatal heart disease.

The y-axis depicts the relative percent of cases from each cause of death. The x-axis depicts the number of years since cancer diagnosis. Each graph represents a patient of the same primary disease site, as indicted by the colors. The colors depict the disease sites as follows: light blue = prostate; dark blue = colon and rectum; pink = breast; white = lung; yellow = bladder; black = melanoma; green = non-Hodgkin lymphoma; orange = kidney; light orange = leukemia; gray = oral cavity and pharynx; coral = endometrial; maroon = myeloma; purple = Hodgkin lymphoma; dark pink = testicular. Grey represents fatal heart disease while all other colors represent death from primary cancer diagnosis. For all sites, the percentage of fatal heart disease cases increases with follow-up time. The largest relative increase in fatal heart disease cases over the follow-up period is seen in endometrial cancer. Myeloma patients are more likely to die from their primary cancer than from heart disease at all time points during the follow-up period. All trend tests for changes in proportion of death from primary cancer versus heart disease are statistically significant (two-sided test; chi-squared value range: 30.9–123,840; P < 0.001). Source data are provided as a Source Data file.