Focal laser ablation uses precisely targeted heat, delivered through a small insertion and guided into the prostate by magnetic resonance imaging, to burn away cancerous cells in the prostate.
A small, phase 1 trial, to published early online in the journal Radiology, found that this approach, designed to treat just the diseased portion of the prostate rather than removing or irradiating the entire gland, is safe and can be performed without the troubling complications associated with more aggressive therapies.
None of the nine men treated in the study had a significant side effect. Six months after therapy, seven of the nine patients (78%) no longer had evidence of cancerous tissue in biopsies of the treated area.
"Focal therapy is the male version of a lumpectomy for breast cancer," said study author Scott Eggener, MD, associate professor of surgery at the University of Chicago Medicine. "Rather than removing the entire organ, we are testing this less-invasive way of destroying just the cancer and leaving healthy tissue in place."
"This experimental approach appears to combine the most attractive element of treatment, eradication of the cancer, with the most appealing element of active surveillance, maintaining quality of life," said Aytekin Oto, MD, professor of radiology and chief of abdominal imaging at the University of Chicago Medicine. "These early safety results are promising, but we definitely need longer-term data."
More than 2 million American men have been diagnosed with prostate cancer. Due to prostate specific antigen testing (PSA), most of these cancers are detected early, long before they cause symptoms. Because this cancer occurs primarily in older men, treatment with radiation or surgery is not always necessary as these are man are much more likely to die from another cause than from prostate cancer.
But many healthy men who are relatively young, with a life expectancy greater than 10 years, are not comfortable deferring treatment of a potentially lethal disease. Surgery and radiation can often cure the cancer, but can cause side effects, such as incontinence, impotence and decreased bowel function.
This study enrolled nine men with biopsy-confirmed, low-risk prostate cancers (Gleason score 6 or 7, less than 12 mm of cancer) with an MRI of the prostate showing a small area of cancer. Patients were treated under conscious sedation while lying in an MRI scanner. After injecting a local anesthetic, the physicians inserted a small catheter across the perineum and used it to guide a tiny optical fiber, the laser and a cooling device into the prostate.
Under MRI guidance, the laser was positioned within the cancer and used to heat the area to a temperature that would kill cancer cells. The team checked the temperatures outside the treatment region every five seconds to protect healthy tissue, especially those near critical structures such as the urethra and rectal wall.
The entire procedure took less than four hours. That decreased to 2.5 hours as the team gained experience. The actual heat treatment averaged 4.3 minutes. All patients left the hospital the same day.
No patient had a major complication or a serious adverse effect. Average scores for urinary or sexual function were not significantly different one, three or six months after treatment. No patient had symptoms of rectal wall damage.
Biopsies of the treated areas six months after the procedure found no evidence of prostate cancer in seven of the nine patients (78%). The other two patients had small (2.5 mm and 1 mm) remaining cancers.
These are preliminary results, the authors caution, following a small number of patients for a short time. It will take much longer follow-up, the authors say, to fully evaluate this approach.
Focal laser ablation is the lastest in a series of efforts to target just the cancer cells and preserve normal areas of prostate. It appears to offer "measurable advantages over other ablative therapies for focal prostate treatment, namely that we can visualize our treatment as it is happening," according to the study authors.
Laser-induced heating can destroy cancer cells with little damage beyond the precisely targeted zone. The approach is well suited for prostate tissue and can be carefully watched in real-time with magnetic resonance imaging, which can also monitor the generation and consequences of the heat treatment.
A phase 2 trial of this procedure, sponsored by the National Institutes of Health, is now underway at the University of Chicago Medicine. The physicians hope to enroll 27 patients. Details are available at the NIH's ClinicalTrials.gov website, identifier: NCT01792024.
The paper, "MR Imaging-guided Focal Laser Ablation for Prostate Cancer: Phase I Trial," appears as an early release in Radiology [doi:10.1148/radiol.13121652]. The study was supported by a research grant from the Partnership for Cures Foundation and by Visualase, the manufacturer of the imaging software and laser ablation tools used in this study. Additional authors include Gregory Karczmar and Walter Stadler of the University of Chicago, and Ila Sethi, Roger McNichols, Karko Ivancevic and Sydeaka Watson of Visualase.
John Easton | EurekAlert!
Laser activated gold pyramids could deliver drugs, DNA into cells without harm
24.03.2017 | Harvard John A. Paulson School of Engineering and Applied Sciences
What does congenital Zika syndrome look like?
24.03.2017 | University of California - San Diego
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy