Noncancer causes of death ‘increasingly pertinent’ among men with advanced prostate cancer
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A substantial number of deaths among men with metastatic prostate cancer resulted from noncancer causes, including cardiovascular disease, according to a retrospective cohort study published in JAMA Network Open.
The findings could help inform the medical community on how men with metastatic prostate cancer should be counseled regarding future health risks and highlight the need for multidisciplinary care of these patients, researchers wrote.
“With the improvement of our armamentarium against metastatic prostate cancer over the past several years, we wanted to evaluate the causes of death in patients with this disease,” Omar Alhalabi, MD, assistant professor in the department of genitourinary medical oncology in the division of cancer medicine at The University of Texas MD Anderson Cancer Center, told Healio. “When a patient is diagnosed with stage IV cancer, some might assume that the cancer is going to be the cause of death most of the time. We wanted to investigate if that is the case regarding metastatic prostate cancer from the SEER database.”
The analysis included 26,168 men with metastatic prostate cancer (mean age at diagnosis, 70.83 years; 48.9% aged 50-70 years; 74.5% white; 72.7% stage M1b disease) diagnosed between 2000 and 2016.
Alhalabi and colleagues calculated standard mortality ratios (SMR) for various causes of death by dividing the observed number of deaths due to each cause by the expected number of deaths in the age-matched U.S. population — based on mortality rates from the National Center for Health Statistics — for the same period. They adjusted analyses for age and race or ethnicity.
Nearly two-thirds (63.9%) of men in the cohort died during the follow-up period (mean age of death, 74.13 years). More than half of the deaths (59%) occurred within 2 years of diagnosis, whereas 31.6% occurred within 2 to 5 years and 9.4% occurred after 5 years.
Results showed 13,011 deaths (77.8%) were due to prostate cancer, whereas 2,797 (16.7%) were due to noncancer causes (SMR = 1.29; 95% CI, 1.24-1.33) and 924 (5.5%) were due to other cancers (SMR = 1.6; 95% CI, 1.5-1.71).
The most common noncancer causes of death during all latency periods included cardiovascular diseases (SMR = 1.34; 95% CI, 1.26-1.42), chronic obstructive pulmonary disease and related conditions (SMR = 1.19; 95% CI, 1.03-1.36) and cerebrovascular diseases (SMR = 1.31; 95% CI, 1.13-1.5).
Within 2 years of diagnosis, a greater percentage of men aged 50 years or older died of causes unrelated to prostate cancer compared with men aged younger than 50 years (21.2% vs. 11.1%; Fisher exact test P < .001).
“Cancer is still the main reason for death (78% of the time). However, in patients who passed away more than 5 years after diagnosis, other causes become increasingly pertinent (33.4%), mainly cardiovascular and cerebrovascular disease,” Alhalabi said.
Most of the results met expectations of the researchers.
“Overall, cardiac disease is an important cause of death, and it was not totally surprising to come right after prostate cancer as a cause of death in our cohort,” Alhalabi said. “We noted that 2% of deaths were due to suicide. Of note, white patients and Asian or Pacific Islander patients had an increased risk [for] suicide, but Black patients and American Indian or Alaska Native patients did not.”
Therapy and follow-up should “be tailored to the needs of each patient” with metastatic prostate cancer and should include counseling on future health risks, Alhalabi added.
Alhalabi and colleagues suggested further investigation into suicide deaths with a larger sample size and future prospective studies aimed at assessing the association of strategies to reduce risk for cardiovascular disease with mortality among men aged 50 and older with metastatic prostate cancer.
Although they acknowledged the limitations inherent to SMR estimates, authors of an editorial accompanying the study wrote the findings were important because most men with prostate cancer are living longer following their diagnosis.
“As such, identifying the causes of deaths among these patients may help with multidisciplinary treatment planning,” Samuel W. D. Merriel, MSc, clinical senior research fellow in the College of Medicine and Health at University of Exeter in the U.K., and colleagues wrote. “[Alhalabi and colleagues] postulate that hormone therapy treatments may increase the risk [for] cardiovascular and cerebrovascular disease in patients treated for metastatic prostate cancer, a theory that is supported by some epidemiological and biomedical evidence. Their finding of increased suicide rates among Asian or Pacific Islander patients and white patients with metastatic prostate cancer is a surprise and should be investigated further, considering that such deaths are potentially preventable.”
References:
Elmehrath AO, et al. JAMA Netw Open. 2021;doi:10.1001/jamanetworkopen.2021.19568.
Merriel SWD, et al. JAMA Netw Open. 2021:doi:10.1001/jamanetworkopen.2021.20889.
For more information:
Omar Alhalabi, MD, can be reached at Department of Genitourinary Medical Oncology, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center, 1155 Pressler St., Unit 1374, CPB7.3538, Houston, TX, 77030; email: oalhalabi@mdanderson.org.