How Does Focal Laser Ablation Work?

A glance back in history reveals that not so many years ago, a prostatectomy to remove prostate cancer was a long and bloody surgery. It meant days in the hospital, a month of recovery, and higher rates of incontinence and ED than today’s robot-assisted laparascopic techniques. In comparison, today’s minimalist focal treatments for appropriate patients seem practically like magic: most patients walk in, a few hours later they walk out, a few days later they’re back at work no worse for wear, and within two weeks the majority are back to their weight training or racquetball or whatever exercise routine they do.

Of course, it’s not magic—just an integration of scientific excellence in biology and physics. I thought I’d demystify what happens during Focal Laser Ablation (FLA), our pioneering MRI-guided treatment that we offer appropriate patients. I’m going to explain each word in “Focal Laser Ablation,” but in reverse order, starting with ablation, which is at the heart of FLA.

Ablation

You Latin scholars will recognize that the verb “ablate” is from the prefix ab (meaning from) and the root lat (a form of the verb that means to carry). Thus, ablate means to carry away from, or out of. In medicine, ablation means the removal of tissue (e.g. organs, abnormal or harmful growths) from the body by mechanical means. As such, ablation technically includes surgically taking something out of the body, but another way to remove a source of danger in the body is to convert it to harmlessness while leaving it in place, rather than cut the body open and using a sharp instrument to carve something out of it. In other words, ablation accomplishes the same goal as surgery: eliminate the threat.

Ablation is an alternative to invasive surgery. It can be done by applying a chemical like ethanol to destroy tissue, but today it is almost universally done with energy, e.g. extreme cold, electricity, light energy (laser), acoustic energy (high-intensity focused ultrasound), radiofrequency, microwave, or a combination of laser plus a sensitizing chemical (photodynamic therapy). All are minimal-to-noninvasive depending on how the energy is applied. All of them are limited to the amount of tissue they can destroy per application, and all of them are calculated to “fit” the targeted tissue plus a wider margin of safety.

Laser

There are many different kinds of lasers that harness the power of light. What distinguishes them is how they are generated, the wavelength used, and the delivery system. In medical use, the laser energy causes intense heat that can do one of three things: cut, vaporize, or coagulate. For example, LASIK eye surgery makes tiny cuts; GreenLight vaporizes the urethral passage to widen it in BPH cases. FLA uses lower temperatures to coagulate prostate cancer tumors.

You learned about coagulation of blood early in life. Kids get cuts and scrapes all the time, and if it weren’t for the ability of blood to quickly congeal, all of us would probably have bled to death before the age of 10. However, tissue coagulation is different from liquid blood turning to a semi-solid or solid.

In tissue, coagulation induces cell death. In FLA, a laser optic fiber is inserted into the target area. When the laser energy reaches the tip of the thin fiber, the tissue begins to heat. The heat has a limited penetration depth, creating a globe-shaped area that is monitored on MRI for size, shape and precise temperature as it encompasses the planned volume of tissue. Whether healthy or cancerous, all the cells included in the “globe” undergo structural and molecular changes that result in immediate cell death. This area is confirmed on MRI before the laser fiber is withdrawn. What is left is called necrotic (dead) tissue. Over time, much of it is simply reabsorbed by the body and eventually excreted as waste. As this scar tissue is reduced, it has the effect of somewhat shrinking the volume of prostate itself. In fact, many of our prostate cancer patients who were experiencing difficulty urinating due to prostate enlargement find that, after FLA for their cancer, when they come in for follow-up, they tell us, “I can pee like I’m young again.”

Focal

Once again taking a peek back in time, the ideal of focal therapy for prostate cancer is quite recent. In the late 1990s, a handful of U.S. doctors were quietly performing focal cryoablation (freezing) of prostate cancer tumors for qualified patients. These doctors were scorned as irresponsible by the vast majority of urologists who had long believed that prostate cancer is a multifocal disease. They assumed that a focal ablation could not help but leave microscopic cancer cells behind, like a ticking time bomb that would eventually kill the patient. However, in the early 2000s and since then, we have learned from pathology evidence that about 30% of cases are truly unifocal. Bursting the bubble of belief about multifocal cancer paved the way to legitimize focal therapy for properly qualified patients, and it is now universally recognized as a legitimate option—for the right patient, of course! It is not surprising, then, that so many energy sources and delivery methods have been, and continue to be, developed in order to do focal therapy for unifocal prostate cancer.

Regardless of the method, focal treatment is thankfully here to stay, with its competitive cancer control and high quality of life. For the Sperling Prostate Center, the choice of laser is a no-brainer. Its controlled precision is safe and efficient, and the ability of multiparametric MRI to plan, guide, monitor and confirm its effectiveness gives us the confidence that we have ablated the targeted tumor.

 

NOTE: This content is solely for purposes of information and does not substitute for diagnostic or medical advice. Talk to your doctor if you have health concerns or questions of a personal medical nature.