The only 'ice' most of our livers
are familiar with is a cold Vodka Ice or possibly Labatt's
Maximum Ice — and we know how 'good' those are for
us. However, ice isn't always such a bad thing for livers,
especially when it's used to freeze tumours. One of the
most promising alternative treatments being developed
for liver cancer is to freeze rogue cancer cells by inserting
a cryoprobe into the heart of the tumour. But cryo-ablation
hasn't been put into practice because it requires very
precise targeting that isn't possible without a good visual
feed in real time. Fortunately, such William Tell accuracy
is now at hand.
A presentation at the Radiological
Society of North America's 90th Scientific Assembly
and Annual Meeting in Chicago this past December described
how magnetic resonance imaging (MRI) literally offers
a glimpse of both the successful targeting of the liver
tumour and the effectiveness of the cryo-ablation procedure.
ICY
STARE
The freezing of a tumour can be followed in real time.
"We can actually watch the iceball grow," said presenter
Dr Kemel Tuncali of Brigham and Women's Hospital in
Boston. "We have better control over the means of killing
the tumour with [MRI] and cryotherapy," continued Dr
Tuncali. "We can also watch out for critical structures
around the area that we don't want to damage, like the
bowel, stomach or gall bladder."
In the study, 31 patients aged
29 to 87 who had a total of 44 liver tumours were treated
with MRI-guided cryotherapy. Two of the patients had
primary liver cancers. The others had cancers that had
spread to the liver. The procedure consisted of 15 minutes
of quick freezing that was followed by a 10-minute thaw,
and then another 15-minute freeze blast.
Of the 44 tumours, 19 were successfully
cryozapped. In fact, just a single treatment was found
to be effective in 17 of the tumours. Masses smaller
than 3.5cm were especially prone to freezing. The success
rate of obliterating smaller tumours was 62% while larger
tumours naturally had a lower degree of success (49%).
Because the procedure was non-invasive,
there was less scarring, recovery was faster and patients
got to go home from the hospital sooner. Moreover, the
longer-term prognosis following the cryotherapy was
good. Overall survival was 77% at 15 months.
SEEING
IS BELIEVING
There were some complications of the treatment including
a short-term rise in bilirubin, a blood clot in the
lung of one patient, clotting and recurrence of a cancerous
nodule. But all were treatable and nonlethal.
"The results of a study like this
show that treating liver tumours and potentially other
tumours with a combination of [magnetic resonance] guidance
and cryotherapy has very promising results," according
to Dr Tuncali. "Not only does it show local success
rates and survival numbers that are encouraging, but
it also demonstrates the usefulness of monitoring with
[magnetic resonance]."
Dr Reed Omary of Northwestern Memorial
Hospital in Chicago described the study results as "promising
for lesions that are very difficult to treat." But,
according to Dr Omary, the proof of the pudding will
require a randomized, controlled study that compares
the freezing blast of cryotherapy with the cell cooking
approach of radiofrequency.
|
