Given a diagnosis of cancer, most patients immediately ask, "Can it be cured? How much time do I have?" And in a new analysis, Duke Cancer Institute researchers say where prostate cancer metastasizes, or spreads, will directly impact a man’s survival time. Patients with metastasis to the lymph alone survive the longest overall, their report indicates. When the liver becomes involved men fare the worst, while those patients who develop a lung or bone metastasis fall in the middle.

"This study is important because of the large number of men that we have analyzed, and confirms that site of metastases is an important factor for survival," Dr. Susan Halabi, a professor of biostatistics, told Medical Daily in an email.

The prostate is a gland found only in men. It sits beneath the bladder and surrounds the urethra, which is the tube that carries urine and semen through the penis. Usually the size and shape of a walnut, the prostate gland makes semen, the fluid that carries sperm. When a man develops prostate cancer, the website of Prostate Cancer UK explains, some men will show no signs of disease, while others may experience one or some of these symptoms:

  • a need to pee more often, especially at night
  • difficulty starting to urinate
  • straining, or taking a long time to finish
  • a weak flow
  • a feeling that the bladder hasn’t emptied properly
  • a need to rush to the toilet, and the occasional leak
  • dribbling urine

Risk factors include older age, a family history, high body weight, and ethnicity. Black men are more likely and Asian men are less likely to be diagnosed with the disease compared to white men, past research indicates.

Castration-Resistant Disease

Because male sex hormones, called androgens, fuel the fire of prostate cancer, a common treatment strategy is to lower a man’s androgen levels. This is done either through surgery or with drugs. If the cancer spreads beyond the prostate, a doctor will often recommend continuing hormone therapy but, for many men, their metastatic prostate cancer will soon become a castration-resistant disease. What this means is the cancer will grow and spread despite being deprived of the hormone it likes.

So, what happens to patients with castration-resistant prostate cancer? Halabi and her colleagues compiled a massive amount of data from nine separate clinical trials involving a total of 8,820 men. The researchers then categorized each patient’s site of metastasis, noting whether the disease spread to the lymph node only, the lymph plus bone, the lung, or the liver.

Nearly three-quarters of the patients had bone metastases. Their median survival rate was just over 21 months.

The longest survival time was for men with lymph involvement only; this group, representing just over 6 percent of the total, had a median survival rate of 32 months.

Men with lung metastases (nearly 9 percent of the total group) had a median survival time of 19 months. Finally, 8.6 percent of the patients — men with liver metastasis — had the worst median survival of nearly 14 months.

prostate cancer
Median Survival for Prostate Cancer Metastases Site Mark Dubowski for Duke Health

"Historically, men with advanced prostate cancer had a median survival of 12 months," said Halabi. "These days the median survival time in this group of men treated with docetaxel [a type of chemotherapy] is 22 months and anywhere up to 36 months. This information could be used to help guide treatment approaches using either hormonal therapy or chemotherapy."

To learn more about prostate cancer, the American Cancer Society is an excellent source of easy-to-read information.

Source: Halabi S, Kelly WK, Ma H, et al. A Meta-Analysis Evaluating the Impact of Site of Metastasis on Overall Survival in Men with Castration-Resistant Prostate Cancer. Journal of Clinical Oncology. 2016.

Note: Comments from Dr. Halabi were added to this story shortly after publication.