Biomedical Engineering Reference
In-Depth Information
MRI/CT and single photon emission CT (SPECT) were used to
assess tumor response. Follow-up images demonstrated com-
plete ablation of malignant bone tumors in 69 patients, with
greater than 50% tumor ablation in the remaining 11 patients.
The one-, two-, three-, four- and five-year overall survival rates
were 93.3%, 82.4%, 75.0%, 63.7%, and 63.7%, respectively, in the
patients with stage IIb cancer, and 79.2%, 42.2%, 21.1%, 15.8%,
and 15.8%, respectively, in those with stage III disease. Among
the patients with stage IIb disease, long-term survival rates were
better in the 30 patients who received the full treatment (com-
plete HIFU and full cycles of chemotherapy) than those in the 24
patients who did not finish the chemotherapy cycles and the six
patients who underwent partial ablation only.
who had complete tumor ablation for curative intent. After
HIFU, hematuria disappeared in 7 of 8 patients and flank pain
of presumed malignant origin disappeared in 9 of 10 patients.
Postoperative images showed a decrease in or absence of tumor
blood supply in the treated region and significant shrinkage of
the ablated tumor. Of the 13 patients, seven died (median sur-
vival 14.1 months, range 2 to 27) and six were still alive with
median follow-up of 18.5 months (range 10 to 27).
In Oxford, United Kingdom, Illing et al.
[110] published
interim results of a prospective, nonrandomized clinical trial to
evaluate the safety and effectiveness of HIFU in the treatment of
small kidney tumors. After a single HIFU session, the patients
were evaluated with either radiological images, such as MRI and
contrast ultrasound, or histological examinations. They found
evidence of ablation in 5 of 10 patients with small RCC. While
compared to open or minimally invasive techniques, the adverse
event profile was favorable. Recently, Ritchie et al. [140] reported
a three-year follow-up result of HIFU ablation for 15 patients
with renal tumors. Among them, mean 30% decrease in tumor
size was observed by contrast-enhanced MRI in 10 patients who
remained on follow-up at a mean of 36 months (ranging from 14
to 55) after HIFU, with a central loss of contrast enhancement.
Four patients had irregular enhancement on imaging and had
alternative therapies. One patient had surgery due to persisting
central enhancement. In addition, Chakera et al.
[141] reported a
case of a localized RCC of recipient origin that developed in the
donor allograft, which was detected eight years after renal trans-
plantation. Treatment with HIFU followed by partial nephrec-
tomy was successful, averting the need for dialysis therapy.
15.7.6 HIFU therapy for renal Cancer
Renal cell cancer (RCC) has the seventh highest incidence of all
cancers in adults, accounting for approximately 3% of all solid
malignancies. At the time of diagnosis, 75% of tumors are organ
confined and as such should be amenable to a local treatment.
RCC is both chemotherapy and radiotherapy resistant. As a
result, the mainstay of treatment for tumors remains surgery,
with five-year survival rates greater than 80% after resection
[13 4].
In the early 1990s, Vallancien et al. [14] reported the first
clinical feasibility study of using extracorporeal USgHIFU
to treat RCC patients. They found evidence of ablation in the
treated areas following excision of the kidney, but encountered
a high rate of skin burns, with 10% of patients suffering this
complication.
In a case report, Kohrmann et al. [135] reported treating a
patient with three renal tumors using a hand-held HIFU device.
Two of the tumors reduced in size following ablation, how-
ever one remained unaffected. Susani
et al.
[136] included two
patients with renal tumors in a phase I trial. They claim accurate
placement of lesions using the HIFU device, but detail is sparse.
Marberger et al. [137] reported a series of 16 patients who had
renal tumors treated with HIFU. In 14 patients a 10 mm
3
volume
of renal tumor was treated with HIFU and this was followed by
immediate surgical resection of the kidney. In nine patients,
areas of acute tissue necrosis were seen, although the lesions
only measured between 15% and 35% of the original targeted
volume. Two patients were treated with curative intent; how-
ever, both had incomplete ablation with residual disease visible
on follow-up MRI. Hacker et al.
[138] described no major side
effects following ablation of tissue in 43 kidneys, porcine and
human, using an experimental handheld extracorporeal tech-
nology. However, technical success was mixed and the authors
concluded that further work was required in the dosage and
application of this system.
We also reported our preliminary clinical experience of using
USgHIFU for the treatment of 12 patients with advanced-stage
renal cell carcinoma and one patient with metastatic kidney can-
cer [139]. All patients received HIFU treatment safely, includ-
ing 10 who had partial ablation for palliative intent and three
15.7.7 HIFU therapy for pancreatic Cancer
Pancreatic carcinoma is the fourth leading cause of cancer-
related deaths in the United States and the Western world.
Nearly 80% of patients have unresectable disease on diagnosis.
There remains no effective modality for the treatment of patients
with locally advanced disease, and chemo-radiation is the cur-
rent best practice although a great deal of debate remains on this
issue. The median survival time is 6-10 months for patients with
locally advanced pancreatic cancer and 3-6 months for patients
with metastatic disease.
From
December 2000 to September 2002, USgHIFU was per-
formed to treat eight patients with advanced pancreatic cancer
for palliative intent [142].
Of these, three patients had stage III
disease, and five patients had stage IV disease. Five of the eight
patients had liver metastases, and one had bone metastasis. All
of the patients had constant localized pain. After HIFU, preex-
isting severe back pain of presumed malignant origin disap-
peared in each patient. Follow-up images showed reduction or
absence of tumor blood supply in the treated region and signifi-
cant shrinkage of the ablated tumor in all patients, ranging from
20% to 70%. Four of the eight patients died (median survival
time 11.25 months, range 2-17 months), and the remaining
four patients were still alive with median follow-up time of 11.5
months (range 9-16 months).
