Welcome to biology-online.org! Please login to access all site features. Create an account.
Log me on automatically each visit
Biology Articles » Cryobiology » Shutting out Soft Tissue Cancers in the Cold
Cryotherapy, an interventional radiology treatment to freeze cancer
tumors, may become the treatment of the future for cancer that has
metastasized in soft tissues (such as ovarian cancer) and in bone
tumors. Such patients are often not candidates for surgery and would
benefit from minimally invasive treatment, say researchers at the
Society of Interventional Radiology's 35th Annual Scientific Meeting in
"Improved treatment options are needed for individuals affected by
metastases in bone and soft tissues since patients with multifocal
metastatic disease are often not candidates for surgery," said Peter J.
Littrup, M.D., an interventional radiologist and director of imaging
research and image-guided therapy for the Barbara Ann Karmanos Cancer
Institute in Detroit, Mich. "Percutaneous soft tissue cryotherapy is a
well-tolerated treatment option, especially for patients with anesthesia
risks, painful lesions or those seeking local control during
chemotherapy. Tumor size and/or location do not preclude thorough
treatment or pose greater risk with appropriate precautions," added
Littrup, who is also a professor of radiology, urology and radiation
oncology at Wayne State University in Detroit.
In the 97-patient study, researchers used sufficient deadly
temperatures to effectively kill tumor cells, resulting in an average of
77 percent tumor shrinkage in patients after 24 months. "Because of the
variable placement of tumors within these soft tissue and bone
locations, this study shows the versatility of this treatment option
when using proper techniques to safeguard nearby structures. Aside from
the successful tumor control, what makes this technique even more
preferable is the excellent tumor shrinkage since the underlying fibrous
or collagenous structures are preserved. The body can then better heal
at the ablation (removal) site with minimal additional scar tissue
formation," said Littrup.
Last year, it was estimated that 1.5 million new cases of cancer were
diagnosed, and up to 85 percent of patients who have breast, prostate
or lung cancer have bone metastases at the time of death. Additionally, 5
percent of all cancers result in skin cancer as well. Based on these
numbers, conservative estimates determine that up to 500,000 of these
newly diagnosed cancer patients alone will suffer from metastatic
disease in bone and soft tissue areas.
Cryotherapy is a good option for a large -- but perhaps
under-recognized -- problem that could deliver a quantum impact. Namely,
the original cancer tumor site (or even a few unresponsive tumors
sites) can still cause cancer management problems even after a generally
good response to chemotherapy and/or radiation therapy, said Littrup.
"Metastasized tumors can occur nearly anywhere in the body and
frequently cannot receive additional radiation therapy or would be
difficult or very morbid to be controlled with surgery," said Littrup.
"Cryotherapy was able to preserve quality of life by providing good
local treatment with minimal side effects, especially with advanced
stages of cancer where any additional treatment is unlikely to provide a
systemic cure," he added. However, cryotherapy is not a first-line
therapy for tumor treatment. Despite "superb" cryotherapy outcomes for
many tumor types and locations, medical insurance may not cover the
treatment, said Littrup.
Historically, cyoablation has been performed on the prostate and
liver, but this technique has been recently found effective in other
tumors including the breast, kidney and lung. "We simply translated this
concept to retroperitoneal, intraperitoneal, superficial and bone
locations in order to generate successful use of cryotherapy in
different patient groups," said Littrup. The major benefits of
cryotherapy are its superb visualization of the ice treatment zone
during the procedure, its low pain profile in an outpatient setting and
its excellent healing with minimal scar, said Littrup.
In this study's cryotherapy treatment, researchers used several
needle-like cryoprobes that were inserted through the skin to deliver
extremely cold gas directly to a tumor to freeze it. This technique has
been used for many years by surgeons in the operating room; however, in
the last few years, the needles have become small enough to be used by
interventional radiologists through a small nick in the skin, without
the need for an operation. The "ice ball" that is created around the
needle grows in size and destroys the frozen tumor cells. Surgeons and
radiation oncologists have long tried to provide at least a 1-centimer
margin of treatment with cancer tumors, and it was important to assure a
similar "surgical margin" of lethal temperatures beyond all tumor
margins by cryotherapy in this study, said Littrup.
"One of our first soft tissue cryotherapy patients with recurrent
ovarian cancer encouraged us to really begin this study. She
appropriately noted that with recurrent cancer, second- and third-line
chemotherapy drugs can run up to $20,000-60,000 per month and that
additional debulking surgery needed at least an additional month of
recovery," said Littrup. This patient has now undergone seven
cryoablation procedures over the last five years in combination with
only a few additional cycles of chemotherapy when more than one to two
recurrences were noted, he said. "She called cryotherapy a major
'holiday' from chemotherapy and has been one of our big advocates,
referring many other ovarian cancer patients with isolated recurrences,"
In the study, 157 computed tomography/CT- and/or ultrasound/US-guided
percutaneous cryotherapy procedures were performed (retroperitoneal,
30; intraperitoneal, 51; superficial, 47; and bone, 29) in 97 patients.
Protection of adjacent crucial tissues (for example, skin, bowel) from
cytotoxic temperatures was achieved by thermocouple monitoring, saline
injection and/or direct skin warming. Patients were followed by CT or
magnetic resonance imaging (MRI). The cryotherapy zone was well-defined
by CT as a hypodense ice ball with an average ablation diameter of 5.4
centimeters; average tumor diameter was 3.5 centimeters.
Interventional radiologists are leaders in percutaneous cryotherapy
because it requires interventional skills and a thorough understanding
of cross-sectional imaging (US, CT, MRI) and IRs are the only physicians
who have this rigorously trained skill set combination, said Littrup.
Continued study is needed to determine the optimum probe number, spacing
and freeze times needed to produce thorough ice coverage of all soft
tissue tumors, he said.
"With recent developments of powerful new cryotechnology, multiple
directions for soft tissue cryotherapy can be pursued, including
translating the current, somewhat challenging, procedure done with
ultrasound and/or CT guidance to a more consistent and reproducible
MR-guided approach," said Littrup. Cryotechnology promises to be more
MR-compatible and would also allow accurate targeting of more
difficult-to-see tumors. More importantly, larger studies in multiple
centers needs to be done, following these basic cryobiology principles
of sufficient lethal temperatures generated by multiple cryoprobes
spaced evenly throughout a cancer region, he added.
rating: 0.00 from 0 votes | updated on: 14 Apr 2010 | views: 1429 |
share this article | email to friends
suggest a revision
print this page
© Biology-Online.org. All Rights Reserved. Register | Login | About Us | Contact Us | Link to Us | Disclaimer & Privacy