can be slow growing, and in less aggressive cases
it may never cause symptoms or need any treatment. But for those who do require
treatment, medications may cause side effects that can affect the quality of
Prostate cancer is monitored through
active surveillance to avoid or delay these side effects or unnecessary
treatment in men with less aggressive condition. Active surveillance is
suitable for men with low risk early stage prostate cancer or even medium stage
cancer that is localized within the prostate gland.
Thanks to the tumor marker, prostate-specific antigen (PSA), it has
been observed that there has been a 75% decrease in the metastatic prostate
cancer. So, radical surgeries such as prostatectomy that may cause
complications like bleeding and pain, and long term problems like rectal
problems or impotence are no longer justifiable.
Focal therapy is the new advancement in prostate cancer treatment.
It is a 'middle ground' alternative between active surveillance and radical
treatment that has shown early cancer cure or control. Focal therapy uses
advanced, targeted diagnostics such as MRI, ultrasonography and the TargetScan
biopsy tool to pinpoint the location of the prostate cancer, and then destroys
only that part of the prostate that is cancerous.
A review study by Takeo Nomura
and Hiromitsu Mimata from the Department of Urology, Oita University Faculty of
Medicine, Japan, discusses the pros and cons of ablative focal therapies
including cryotherapy, high-intensity focused ultrasound (HIFU), and
vascular-targeted photodynamic therapy (VTP). A brief summary is presented
Cryotherapy - This therapy involves controlled freezing of the
prostate with probes placed into specific locations of the prostate and cooled
to a very low temperature and then thawed. This freezing and thawing destroys
the cancer cells and blood vessels that feed it. 'Current technology uses argon
gas or liquid nitrogen circulating through hollow needles to freeze the
prostate and helium gas to warm the urethra via the Joule-Thompson effect',
found the reviewers.
Cryotherapy is suitable for
patients with low-risk (clinical stage T1c-T2a disease, Gleason grade 6, and
PSA less than 10 ng/mL) and patients with intermediate risk (Gleason grade 7,
PSA between 10 and 20, or clinical T2b). It is also suitable for cancer
patients with previous pelvic radiation or pelvic surgery, irritable bowel
disease, cardiac disease or extreme obesity.
Cryotherapy is not done in -
• In cases where the tumor is present near the urethra
since the urethral warming catheter will prevent complete eradication of
• In cases where the tumor cells
are found near the neurovascular bundles.
• In patients with severe lower
urinary tract symptoms or large prostate.
Common complications include
erectile dysfunction and impotence. Penile numbness, pain in the pelvis area
and rectum, and urethral stricture is also common in patients who had
cryotherapy. Rarer complications include swelling of the penis and scrotum.
High-Intensity-Focused Ultrasound (HIFU) - This non-invasive
therapy involves using high energy sound waves that raises the temperature of
the cancer cells to more than 80 degree Celsius and effectively destroys
cancerous tissue without damaging the surrounding tissues. HIFU is suitable for
patients who are over 70 years of age falling in the low- and intermediate-risk
The disadvantages of this
procedure include -
• It is a long duration procedure as it may take up to
several months for cancer cell death to occur.
• It is difficult to destroy
cancer cells in a large prostate.
• There is difficulty in ablating
anterior cancers (cancer cells in the anterior region of the prostate).
• This procedure may not be
effective for prostate with high calcifications (greater than 1cm) as they will
obscure ultrasonographic visualization.
• It is also not recommended for
patients who cannot tolerate radical prostatectomy or radiation therapy.
Common complications include
transient urinary retention arising from swelling of the prostate after the
Vascular targeted photodynamic therapy (VTP) - This is a
non-surgical technology where a photosensitizing agent is injected into the
bloodstream which is then absorbed by all the cells in the body remaining
longer in the cancer cells than in the normal cells. The tumor is exposed to
light within 24 to 72 hours. The photosensitizing agent absorbs the light and
produces radical oxygen species (oxygen ions and peroxides) that destroy the
blood vessels feeding the tumor. This technique is still under investigation.
The disadvantage of this therapy
is that the photosensitizers take a long time to be cleared from the body and
get accumulated in the skin. So, patients have to be protected from sunlight
for several weeks after the treatment to avoid sunburn-like reactions. However,
new photosensitizers have been developed now that are cleared rapidly from the
blood stream and then from the liver negating the need for sunburn protection.
The clinical data revealed that,
in general, VTP using WST09 is safe and 'well tolerated with no serious adverse
events including incontinence, tissue sloughing, and rectal injury'. However,
patients undergoing VTP therapy using the photosensitizer
mTHPC may have side effects such as rectourethral fistula, urinary
retention, and urethral stricture.
By analyzing the available data,
the reviewers concluded that -
• 'The goal of focal therapy is to selectively ablate
known disease, while minimizing lifetime morbidity without compromising life
• Focal therapy is for patients
with 'low-grade, low-volume disease that can be easily characterized'.
• 'Cryotherapy and HIFU emerged
as pioneers in focal therapy showed a lot of promise but still need a long-term
follow-up for assessing quality of life and cancer-specific and overall
survival before the indications for primary or salvage therapy can be
• 'VTP therapy needs 'careful
patient specific planning since there is significant variability in the dose
distribution and consequent tissue response'.
• '3D-mapping prostate biopsy,
histoscan, and MpMRI can accurately detect prostate cancer cells.'
• 'A further novel imaging tool
for identifying individuals is desirable in careful preoperative patient
Source: Nomura, T.
and Mimata, H. Focal Therapy in the Management of Prostate Cancer: An Emerging
Approach for Localized Prostate Cancer. Advances in Urology, vol. 2012, Article
ID 391437, 8 pages, 2012.