Nearly 80% of men with metastatic prostate cancer died from their malignancy, according to a retrospective cohort study involving 26,000-plus American men diagnosed with advanced disease in roughly the last 20 years.

The findings fill an information gap because, remarkably, “data are lacking” on causes of death among men whose prostate cancer has spread to other sites, say lead author Ahmed Elmehrath, MD, of Cairo University, Cairo, Egypt, and colleagues.

“It was an important realization by our team that prostate cancer was the cause of death in 78% of patients,” said senior author Omar Alhalabi, MD, of University of Texas MD Anderson Cancer Center, Houston, in an email to Medscape Medical News.

“Most patients with metastatic prostate cancer die from it, rather than other possible causes of death,” confirm Samuel Merriel, MSc, Tanimola Martins, PhD, and Sarah Bailey, PhD, University of Exeter Medical School, Exeter, United Kingdom, in an accompanying accompanying editorial. The study was published last month in JAMA Network Open.

The findings represent the near opposite of a commonly held — and comforting — belief about early-stage disease: “You die with prostate cancer, not from it.”

That old saying is articulated in various ways, such as this from the Prostate Cancer Foundation: “We can confirm that there are those prostate cancers a man may die with and not of, while others are very aggressive.” The American Cancer Society says this: “Prostate cancer can be a serious disease, but most men diagnosed with prostate cancer do not die from it.”

However, these commonplace comments do not cover metastatic disease, which is what the authors of the new study decided to focus on.

The team used data from the Surveillance, Epidemiology, and End Results Program (SEER) database to gather a sample of 26,168 US men who received a diagnosis of metastatic prostate cancer from January 2000 to December 2016. They then analyzed the data in 2020 and found that 16,732  men (64%) had died during the follow-up period.