Perineural invasion means prostate cancer is present inside a nerve in the prostate. This may provide important information about a person’s outlook, but it is not the most important factor in determining how aggressive a cancer is.

As many as 84% of prostate cancers feature perineural invasion. It may mean the prostate tumor has metastasized, or spread outside the prostate.

When a doctor suspects prostate cancer, they will order a biopsy, which is a tissue sample that a lab then examines. The pathology report from the lab will provide important information about the cancer, including whether it has spread into or around a nerve.

This article will explain what perineural invasion in prostate cancer means, along with its symptoms, causes, and treatment.

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Perineural invasion prostate cancer is when the cancer has spread from the prostate to a nerve in or around the prostate. It is one sign that the cancer has spread outside the prostate, but it is not the most important sign.

Research on the meaning of perineural invasion has mixed results. Some data suggest that perineural invasion may point to a worse outlook, but other data suggest there is no correlation.

What is prostate cancer?

The prostate is a gland that makes seminal fluid, an important component of semen. It sits in the groin between the base of the penis and the rectum, and a doctor can examine it via a rectal exam.

Prostate cancer is the most commonly diagnosed cancer in males and the sixth-leading cause of cancer deaths.

The outlook for those with prostate cancer is usually good, especially with treatment. The American Cancer Society (ACS) reports a 97% overall 5-year survival rate. However, cancer that spreads to distant locations has a survival rate of around 32%.

Learn more about prostate cancer.

A person cannot diagnose prostate cancer or determine how far it has spread based on symptoms. In the early stages, prostate cancer usually causes no symptoms. When it does cause symptoms, they may include:

  • frequent urination, especially at night
  • painful urination
  • weak urine stream
  • blood in the urine

Advanced prostate cancer may cause symptoms such as:

No single cause explains all cases of prostate cancer. Genetics may play a role, and certain genetic risk factors, such as the BRCA1 gene, may increase the risk of developing more aggressive prostate cancer.

Lifestyle factors are also important. A typical Western diet that is rich in processed foods and saturated fat increases the risk of prostate cancer. Certain risk factors also play a role, including:

Perineural invasion is a sign that cancer is spreading. It may occur if the cancer is more aggressive or goes undetected for a long period.

A doctor can diagnose prostate cancer based on a biopsy, which involves taking a sample of tissue from the prostate and sending it to a lab for analysis. A biopsy can show perineural invasion.

A doctor may also recommend imaging tests, such as an MRI of the prostate, or genetic testing.

Because perineural invasion is not the most important indicator of a person’s outlook, a doctor will likely rely on other data. One of the most important measures of outlook is the Gleason score, which gauges how aggressive the cancer is.

Cells steadily change as they become cancerous. The Gleason score measures how significantly they have changed on a scale of 1 to 5. A score of 5 indicates a very aggressive cancer with no normal cells present.

Learn more about a prostate biopsy.

Treatment depends on many factors, including a person’s overall health, the genetics of the cancer, and how advanced the cancer is. Perineural invasion does not determine treatment. Treatment options include:

In the United States, the 5-year survival rate among people who have localized disease that has not spread far outside the prostate is nearly 100%. They are also unlikely to die of prostate cancer within 15 years.

As the disease spreads, the outlook worsens, with a 5-year survival rate of around 29% with the most aggressive cancers.

Research on the role of perineural invasion in prostate cancer outlook is inconsistent. A 2023 study of 198 men with perineural invasion found they had lower rates of grade reclassification-free survival. This means the cancer was more likely to spread and lead to reclassification among this group.

Other studies undermine this claim, and the exact role of perineural invasion remains uncertain.

5-year survival rate

The 5-year survival rate is the percentage of people in a treatment group who are still alive 5 years after receiving a diagnosis or beginning treatment.

Was this helpful?

Perineural invasion is one way to assess prostate cancer and may provide some information about its spread. However, it is not the most important factor, and studies on its role in predicting the outcome are inconsistent.

People with prostate cancer should discuss the meaning of their specific pathology report with an oncologist. Many factors will help with determining the right treatment and outlook.