In the ancient world, there were endless tales about the epic deeds of heroes like Jason, who set out with a band of fellow argonauts to find the Golden Fleece.
Today, we know these deeds are myths, but we now have researchers conducting a very real, historic argosy for a liquid biopsy that could diagnose prostate cancer (PCa) without invasively poking holes in the prostate gland. They are searching for a way to analyze a blood or urine sample that would provide information so detailed that an accurate treatment plan could be made!
Much progress has already occurred. PCa cells “leak” clues, or biomarkers, into bodily fluids. They consist of measurable, detectable biological matter that ranges from molecules to entire cells. For example, circulating tumor cells that break away and begin to travel in blood or lymphatic fluid can be isolated and counted. Other types of matter include circulating tumor DNA, extracellular vesicles, etc. It’s possible to sample blood or other fluid and use it to extract and analyze these tiny particles. They can not only reveal that cancer is present somewhere in the body, but can even help profile it. This is important, because it can make the difference in planning a treatment.
With all of that, why do we still need to sample tissue from the prostate gland? Not only are prostate biopsies uncomfortable—even painful—if proper anesthetics are not used, there are side effect risks. However, the tumor cells themselves as well as their location, shape and size of the mass are the foundation for determining whether treatment is needed for significant PCa, and if so, the most effective treatment match with the least impact of quality of life. A liquid biopsy can help determine cellular and genomic content, but can’t give the anatomy of a tumor, or the potential diversity of cell lines and levels of aggression contained in a single tumor.
There’s a saying, “If the only tool you have is a hammer, you’ll see every problem as a nail.” When it comes to prostate cancer, if the only treatments we had were prostatectomy or whole-gland radiation, you might be tempted to think that specific tumor information wasn’t required. After all, if you’re going to remove the whole gland, or bombard it with radiation, wouldn’t that handle the PCa? Why take extra time and money to get to know it better, if it’s all going to be gone or destroyed anyway?
There are two responses to that line of thinking:
- There’s no 100% guarantee that a tumor is both truly confined and also nonaggressive. There are many different cells lines, and some are more dangerous than others. Did you know that prostatectomy failure rates can be as high as 25%, even as late as 15 years out from surgery? Even when the surgeon says, “We got it all,” patients are rightly mystified when their PSA begins to rise years later. What if more had been known about their cell line before they went under the knife?
- Today we have a recipe for tailored treatment that relies on three ingredients: multiparametric MRI (mpMRI) before biopsy, in-bore MRI-guided targeted biopsy using fewer needles, and the genomics from actual tumor cells obtained from biopsy. The currently available liquid biopsies can round these out.
Such specific information makes sense, because there are excellent focal therapy alternatives to radical surgery and radiation. The success of focal treatment completely depends on a thorough, detailed portrait of each patient’s PCa as well as his lifestyle needs and preferences.
Think of it like buying a new car. If all you want is a way to get from one place to another, you won’t spend much time shopping for the “right” vehicle because any of them will fit the bill. However, if you want specific features for certain purposes, you won’t choose a BMW sedan if you’re an off-roader. You won’t buy a Ferrari 2-seater if you need to accommodate two growing teens, their sports equipment and groceries. You won’t want an SUV if only a Corvette will satisfy your changing midlife self-image. Instead, you’ll examine your needs and preferences, and then research makes and models, talk to other drivers, read consumer reports, etc. In short, you gain all the information you can in order to fine-tune your ultimate purchase so it’s the “right” car for you.
It’s the same with gaining all you can know about your PCa. The current approaches to liquid biopsy cannot yet provide that definitive initial PCa diagnosis sufficient for treatment planning. On the other hand, sophisticated sampling of bodily fluids can not only supplement a biopsy-proven diagnosis with more information such as the number of circulating tumor cells, they are of increasing value for tracking response and success after treatment when combined with PSA plus mpMRI.
So yes, needle biopsies are still necessary to diagnose PCa—and the Sperling Prostate Center offers the best type of prostate biopsy—but day is coming when 3T mpMRI plus Artificial Intelligence plus liquid biopsy will eventually replace needles.
NOTE: This content is solely for purposes of information and does not substitute for diagnostic or medical advice. Talk to your doctor if you are experiencing pelvic pain, or have any other health concerns or questions of a personal medical nature.