Is That Prostate Cancer Worth Treating? Chromosomes May Tell

MONDAY, May 13, 2019 (HealthDay News) -- To treat, or not to treat: That remains one of the tough conundrums for men with prostate cancer and their doctors, because some tumors may be aggressive, while others may take decades to cause harm.

Now, new research suggests that tracking specific changes in the number of chromosomes inside prostate cancer cells might help solve the riddle.

Besides giving new insights into how prostate tumors form and spread, the chromosomal data might someday "be employed clinically to inform risk stratification and treatment" decisions for patients, according to a team led by Angelika Amon, of the Massachusetts Institute of Technology.

The research focuses on a genetic state known as aneuploidy -- an abnormal number of chromosomes in cells. Aneuploidy is a known hallmark of cancer, but it's unclear how it influences cancer progression, or whether tracking chromosome gains or losses might help guide treatment.

Treatment guidance for prostate cancer is sorely needed, said Dr. Manish Vira. He helps direct urologic research at Northwell Health's Arthur Smith Institute for Urology, in Lake Success, N.Y.

That's because use of the prostate-specific antigen (PSA) blood test has fallen out of favor somewhat as a means of gauging whether a man needs surgery or other treatment, Vira said. In many cases, the tumor might turn out to be "indolent" -- so slow-growing that it's better to leave it in place and simply "watch and wait."

So, "the holy grail in prostate cancer remains to be finding a test, given at the time of diagnosis, that can identify the subset of patients that are at highest risk of dying of prostate cancer," explained Vira, who wasn't involved in the new study.

In this study, Amon's group was seeking just such a test.

The investigators used prostate tumor samples from 333 men to develop a method to estimate a "signature" pattern of chromosomal gains and losses within cells.

They then applied this method to 404 prostate cancer patients who were followed for a median of 15 years.

Compared to those who had no predicted aneuploidy, the 23% of patients whose tumors had five or more predicted chromosome arm alterations at the time of diagnosis were 5.3 times more likely to die of prostate cancer during follow-up, the findings showed.

Even among high-risk patients, the degree of tumor aneuploidy predicted future deadly prostate cancer, according to the study published May 13 in the Proceedings of the National Academy of Sciences.

The findings suggest that aneuploidy does play a key role in aggressive prostate cancer, Amon's team said, and that the extent of aneuploidy could be used to determine the level of risk from the cancer and to help make treatment decisions.

Vira agreed the tool has potential, and "could be used on prostate biopsy samples to further stratify patients at the time of diagnosis."

Dr. Nicholas Karanikolas directs urologic oncology at Staten Island University Hospital in New York City. Reading over the new findings, he agreed that oncologists need "a broader understanding of the genetic makeup of the cancer itself" to help guide treatment.

Any test that might tell men they have a fivefold higher odds of dying from a prostate cancer "would provide further guidance as to those patients who would benefit from adjuvant treatments and/or inclusion in clinical trials," Karanikolas said.

More information

The U.S. National Cancer Institute has more on prostate cancer.