Genomic Testing Shows Promise for Metastatic Prostate Cancer

By Stephanie Murg, Managing Director, G2 Intelligence

On the heels of last week’s White House Precision Medicine Summit, new research findings suggest that a personalized approach can benefit patients with advanced prostate cancer. According to a study published in the March issue of Nature Medicine, tissue from a single metastasis can provide molecular information to help guide therapy in metastatic prostate cancer.

Although primary tumors can be managed by surgery or radiation, there are few effective treatments for metastatic cancer. Precision medicine approaches will only work if the metastases are not heterogeneous: that is, an individual’s tumors must share a similar set of characteristics so that they may be targeted accordingly. Researchers at Fred Hutchinson Cancer Research Center (Seattle) set out to determine whether prostate cancer metastases are good candidates for precision oncology: homogeneous within patients, but heterogeneous between patients.

The researchers evaluated primary or metastatic tumors from 176 men. The tissue was analyzed to determine characteristics such as copy number alterations and gene expression. Whole-exome sequencing was also used.

They found limited genomic diversity within patients, meaning that a single metastasis provided complete molecular and genetic information. The presumptive “driver” mutations—those that contribute to tumor progression—generally occurred within all metastases tested from a single individual, while the mutations that were found to be unique to specific tumors were generally not predicted to be detrimental. Substantial differences in genomic alterations were found between individuals.

“If you look in multiple metastases within a given patient, they’re actually very, very similar,” said senior author Peter S. Nelson, Ph.D., a member of the Human Biology, Clinical Research, and Public Health Sciences divisions at Fred Hutch. “They’re not identical, but in terms of the key features of a cancer that would inform how best to treat that cancer we can feel generally confident, at least with prostate carcinoma, that if you did sample a single tumor, you could make clinical decisions based on what you find.”