Metastatic prostate cancer can develop in other ways. In some men the disease progresses quickly, while in other men the cancer progresses slowly and has a greater prognosis. Researchers are developing a wide range of tools to predict how quickly prostate cancer may progress. The most promising are assays that count circulating tumor cells (CTCs) in blood samples.
Prostate cancer spreads by shedding CTCs into the bloodstream, so higher blood counts often reflect worse disease. Sometimes often called a liquid biopsy, the CTC assay may also help doctors resolve whether patients should undergo standard or more aggressive treatment. There is currently just one CTC assay available on the market for prostate cancer. Called CellSearch, its use has to date been limited to men with late-stage metastatic cancers for which hormonal treatments are not any longer effective.
Use of CTC data
Hormonal treatment blocks testosterone, a hormone that drives prostate tumors to grow. Research shows that top numbers of CTCs predict poor survival and rapid disease progression in patients with metastatic prostate cancer. who grow to be immune to this manner of treatment. But recent Research shows that CTC count can also be predictive. Initial stage Metastatic prostate cancer that also responds to hormonal therapy.
Why is that this vital? The earlier doctors can predict the cancer's trajectory, the higher their ability to pick out patients who might profit from a stronger (and possibly more aggressive) drug combination or clinical trial. Conversely, men who're older or frail could also be treated less aggressively if doctors have higher insight into their prognosis.
How was the study conducted?
Investigators collected blood samples from 503 newly diagnosed patients with hormone-sensitive metastatic prostate cancer who were enrolled in a clinical trial with experimental hormonal therapy. The team collected baseline samples at trial registration, after which one other set of samples after treatment was now not working. CTC counts were divided into three categories:
- More than 5 CTCs per 7.5 milliliters (mLs) of blood
- Between 1 and 4 CTCs per 7.5 ml of blood
- Zero CTCs per 7.5 mL of blood.
What did the research show?
The results showed that men with higher baseline CTC counts fared worse no matter which cancer drugs they were taking. Median survival for men with 5 or more CTCs was 27.9 months compared with 56.2 months for men with 1 to 4 CTCs. Patients with 0 CTC didn't have enough deaths to calculate survival rates.
Similarly, higher CTC counts predicted faster onset of resistance to hormonal therapy: 11.3 months for men in the best CTC category, 20.7 months and 59 months for men with 1 to 4 and nil CTC, respectively. Competitions. Importantly, high CTC counts correlate with measures of prostate cancer severity, including PSA levels, variety of bone metastases, and other indicators.
Observations and comments.
“It remains to be determined how this type of testing compares with traditional assessments of disease progression, such as X-rays, bone scans, and other forms of imaging. More invasive biopsies of metastatic deposits would be a welcome addition to the methodology – especially if future studies show that CTCs inform more accurate treatment choices.”