Cancer Treatment Today

Image-guided ablation of tumors is assuming an increasingly important role in many oncology services as a minimally invasive alternative to conventional surgical interventions for patients who are not good candidates for surgery.  Laser-induced thermal therapy is a percutaneous tumor-ablation technique that utilizes high-power lasers placed interstitially in the tumor to deliver therapy.  Multiple laser fibers can be placed into the treatment volume and, unlike other interstitial heating techniques, can be fired simultaneously to rapidly treat large volumes of tissue.  Modern systems utilize small, compact, high-power laser diode systems with actively cooled applicators to help keep tissue from charring during procedures.  Additionally, because this approach to thermal therapy is easily made magnetic resonance compatible, the incorporation of magnetic resonance imaging (MRI) for treatment planning, targeting, monitoring, and verification has helped to expand the number of applications in which LITT can be applied safely and effectively.  These investigators provided an overview of the clinically used technology and algorithms that provide the foundations for current state-of-the-art MR-guided LITT (MRgLITT), including procedures in the bone, brain, liver, and prostate as examples.  In addition to advances in imaging and delivery, such as the incorporation of nanotechnology, next-generation MRgLITT systems are anticipated to incorporate an increasing presence of in silico-based modeling of MRgLITT procedures to provide human-assisted computational tools for planning, MR model-assisted temperature monitoring, thermal-dose assessment, and optimal control.

This is a new technique. The most recent paper by Lepor et al (2015) reported that from April 2013 to July 2014, a total of 25 consecutive men participated in a longitudinal outcomes study following in-bore MRgFLA of PCa. Eligibility criteria were clinical stage T1c and T2a disease; prostate-specific antigen (PSA) less than 10 ng/ml; Gleason score less than 8; and cancer-suspicious regions (CSRs) on multi-parametric MRI harboring PCa. CSRs harboring PCa were ablated using a Visualase cooled laser applicator system. Tissue temperature was monitored throughout the ablation cycle by proton resonance frequency shift magnetic resonance thermometry from phase-sensitive images. There were no significant differences between baseline and 3-month mean American Urological Association Symptom Score or Sexual Health Inventory in Men scores. No man required pads at any time. Overall, the mean reduction in PSA between baseline and 3 months was 2.3 ng/ml (44.2 %). Of 28 sites subjected to target biopsy after FLA, 26 (96 %) showed no evidence of PCa. The authors stated that the findings of this study provided encouraging evidence that excellent early oncologic control of significant PCa can be achieved following FLA, with virtually no complications or adverse impact on quality of life. Moreover, they stated that longer follow-up is needed to show that oncologic control is durable. These researchers stated that early results for focal laser ablation of PCa are very encouraging; however, until long-term oncologic control is confirmed, focal laser ablation must be considered an investigational treatment option.

There is currently insufficient evidence to support the use of focal laser ablation for the treatment of prostate cancer.  The oncologic efficacy of MRI-guided FLA is currently being evaluated in several phase II clinical studies.

References:

Lepor H, Llukani E, Sperling D, Fütterer JJ. Complications, recovery, and early functional outcomes and oncologic control following in-bore focal laser Ablation of prostate cancer. . Eur Urol. 2015 May 12

Lee T, Mendhiratta N, Sperling D, Lepor H. Focal laser ablation for localized prostate cancer: Principles, clinical trials, and our initial experience. Rev Urol. 2014;16(2):55-66.

COI Attestation – Peer Clinical Reviewer (Case Specific) Case #: HR048182 Patient Name / Initials: Frank A. Gourley, Jr. Benefit Plan: BlueCross BlueShield of North