In a study reported in JAMA Network Open, KC et al identified factors involved with primary cancer mortality vs noncancer mortality among long-term survivors of breast, prostate, and colorectal cancers.
Study Details
The study included data on 627,702 patients in the Surveillance, Epidemiology, and End Results (SEER) registry with breast (n = 364,230), prostate (n = 118,839), or colorectal cancer (n = 144,633; 104,488 with colon and 40,145 with rectal cancer) who were diagnosed between January 2003 and December 2014. They received definitive treatment for localized disease and were alive 5 years after diagnosis. Based on established risk factors of cancer-specific mortality, patients in each cancer cohort were categorized as being at low, intermediate, or high risk. Follow-up ended in 2019.
Key Findings
In the breast cancer cohort, two-thirds of deaths were the result of causes other than the primary cancer, with heart disease accounting for one-quarter. In the prostate cancer cohort, more than three-quarters of deaths were the result of noncancer causes, with heart disease accounting for one-quarter. In the colorectal cancer cohort, more than two-thirds of deaths were the result of noncancer causes, with one-third from heart disease.
Factors associated with shorter median cancer-specific survival included stage III disease in patients with breast cancer (survival time ratio [TR] = 0.54, 95% confidence interval [CI] = 0.53–0.55) and colorectal cancer (TR = 0.60, 95% CI = 0.58–0.62 for colon; TR = 0.71, 95% CI = 0.69–0.74 for rectal), and Gleason score ≥ 8 in prostate cancer (TR = 0.61, 95% CI = 0.58–0.63).
For all cohorts, patients at low risk had at least a three-fold higher rate of noncancer mortality vs cancer-specific mortality (all P < .001) at 10 years from diagnosis: a cumulative incidence of 20.9% vs 3.2% (ratio = 6.7) for breast cancer, 14.2% vs 1.7% (ratio = 8.6) for prostate cancer, 30.6% vs 4.4% (ratio = 7.0) for colon cancer, and 26.5% vs 8.5% (ratio = 3.1) for rectal cancer.
Patients at high risk had a higher cumulative incidence of cancer-specific mortality vs noncancer mortality in all cohorts except the prostate cancer cohort (all P < .001): 6.0% vs 8.1% (ratio = 0.4) for breast cancer, 6.0% vs 3.4% (ratio = 1.8) for prostate cancer, 5.9% vs 9.3% (ratio = 0.6) for colon cancer, and 5.6% vs 13.5% (ratio = 0.4) for rectal cancer.
The investigators concluded: “This study is the first to date to examine competing oncologic and nononcologic risks focusing on long-term adult survivors of cancer. Knowledge of the relative risks facing long-term survivors may help provide pragmatic guidance to patients and clinicians regarding the importance of ongoing primary and oncologic-focused care.”
Michaela A. Dinan, PhD, of the Department of Chronic Disease Epidemiology, Yale School of Public Health, is the corresponding author of the JAMA Network Open article.
Disclosure: This research was supported by the American Cancer Society. For full disclosures of the study authors, visit jamanetwork.com.
