There are several other minimally invasive treatment technologies that utilize a variety of mechanisms to destroy prostate tissue by heat, oxidation, etc. Most are investigational and should be considered only if available in a clinical trial. While long-term data is not available for treating the full prostate, these treatments may be more applicable to focal therapy (see below). Examples include:
High Intensity Focused Ultrasound (HIFU) HIFU relies upon coagulative necrosis from elevated temperatures to destroy tissue. Using the focused ultrasound energy converted to heat, a precise demarcation between treated and untreated tissue is expected. While HIFU is investigational in the USA, it is available in many areas outside the USA.
Image-guided Targeted Laser Ablation is a transperineal photothermic therapy using a laser system with transrectal ultrasound-guidance. Using a perineal grid, similar to that used for brachytherapy, laser treatment fibers are placed into the known coordinates of the prostate tumor. This laser technology produces a heat lesion, which is monitored by thermistors.
Irreversible Electroporation (IRE) is a new non-thermal ablation modality (referred to as NanoKnife®) that uses short pulses of DC electric current to create irreversible pore in the cell membrane, thus, causing cell death. The NanoKnife has FDA approval for use in destroying tissue but few published studies of use for cancer.
Laser Activated Nanoparticles – Carbon nanoparticles activated by bursts of laser light trigger the tiny blasts, which open holes in cell membranes just long enough to admit therapeutic agents contained in the surrounding fluid. There are few published studies of use for cancer.
Photodynamic Therapy (PDT) is a treatment that uses a drug, called a photosensitizing agent, and a particular type of light. When photosensitizers are exposed to a specific wavelength of light, they produce a form of oxygen that kills nearby cells. Each photosensitizer is activated by light of a specific wavelength. This wavelength determines how far the light can travel into the body. In the first step of PDT for cancer treatment, a photosensitizing agent is injected into the bloodstream or taken as an oral agent. The agent is absorbed by cells all over the body, but stays in cancer cells longer than it does in normal cells.
Radio Frequency Ablation (RFA) destroys prostatic tissue inside the prostatic capsule through heating. At the same time the anatomical structures surrounding the prostate are being preserved. The energy is deployed through a tiny probe that is inserted into a small incision close to the tumor.
What is Focal Therapy?
Modern pathologic data indicate that focal therapy – which limits treatment to the cancerous area alone – can be a curative treatment option. This concept, in practice, is in its early stages. Focal energy therapies are being evaluated for primary treatment of localized and focal prostate cancer. With improvements in imaging modalities that allow the delineation of areas of tumor and improvements in delivery of therapy, focal treatment of localized prostate cancer may help maximize cancer therapy and minimize treatment morbidity.
Multiple possibilities for focal treatment of localized prostate cancer exist including:
- Cryotherapy – currently being performed but considered investigational
- Focal Brachytherapy – currently available but considered investigational
- HIFU – available outside the USA
- Irreversible Electroporation (IRE) – investigational
- Indigo Laser – investigational
- Laser Activated Nanoparticles – investigational
- Photodynamic therapy – investigational
- Radio Frequency Ablation (RFA) – investigational
- Has the Time Come for Focal Therapy of Prostate Cancer? • Martin J Weissman, M.D. 2008
- Review of Focal Therapy for Localized Prostate Cancer PDF 2010
- Transrectal High Intensity Focused Ultrasound: The Next Generation? • HIFU • Douglas O. Chinn, MD 2005
- HIFU Treatment Outcome Data Is Maturing PDF
- Focal Therapy for Prostate Cancer Rev Urol. 2008 Winter; 10(1): 81–82. Makarov, D, Partin, A
- Focal Therapy of Prostate Cancer – Duke University
- FAQS about Focal Therapy for Prostate Cancer – NYU Langone Medical Center
Page updated 8/1/11