What Mayo Clinic is doing to better manage low-risk prostate cancer

Because of the high volumes, Mayo Clinic urologists have the opportunity to tap into a burgeoning database of valuable prostate cancer information. Clinical data, tissue and serum samples, and treatment follow-up data are included in an extensive database. This compiled information gives urologists the data to help develop markers on prostate cancer, diagnostic tests and novel treatments for the diagnosis and treatment of those with low-risk prostate cancer.

For those patients whose prostate cancer is considered to be low risk, about 50 percent per year, or 100,000 men, most might not require aggressive treatment. Prostate-specific antigen (PSA) screening identifies most prostate cancers, but does not always delineate between high-risk and low-risk tumors, in particular for PSAs less than 10 ng/mL.

The majority of men with low-risk prostate cancer choose active treatment (radiation or radical prostatectomy) rather than active surveillance. Urologist R. Jeffrey Karnes, M.D., at Mayo Clinic in Rochester, Minn., explains, "With active surveillance, there are still a lot of unknowns as to what the potential of the cancer might be."

To solve this conundrum, Mayo Clinic is working on a gene-based prostate prognostic test to distinguish indolent tumors from aggressive ones. "We are looking at the DNA of these cancers and trying to sort out the differences between an insignificant cancer and a significant one, even when on the surface they all appear to be low risk," says Dr. Karnes.

A multidisciplinary group of Mayo Clinic scientists have joined forces in the development of this gene-based prostate diagnostic test. Researchers are analyzing DNA alterations of prostate tumor cells to weed out significant cancers from insignificant ones.

To develop this gene-based test, Mayo Clinic researchers utilized a combination of technologies to analyze DNA alterations of four groups of tumors:

  • Indolent, large volume Gleason 6
  • Both patterns of Gleason 7 (4+3 and 3+4)
  • A group of Gleason 8 cancers

Laser capture microdissection (LCM) was utilized to capture cells, followed by DNA amplification techniques. DNA changes were analyzed using high-throughput generation sequencing, which provided a revolutionary platform to unravel the precise DNA aberrations concealed within subgroups of tumor cells.

The researchers found that this novel methodology aids in the derivation of genomic aberrations that initiate cancer and drive cancer progression. "In the future, we hope this test or similar ones will be a valuable tool in guiding treatment decisions," says Dr. Karnes. "Patients who have a genetic profile of their prostate cancer at Mayo Clinic might better be able to tell if the cancer is an indolent one or a more significant one."

Feb. 20, 2014