AJR 2002; 178:1481-1482
© American Roentgen Ray Society
Radiofrequency Ablation of Colorectal Splenic Metastasis
Anna Marangio1,
Ubaldo Prati2,
Ombretta Luinetti3,
Enrico Brunetti1 and
Carlo Fìlice1
1 Divisione di Malattie Infettive e Tropicali, IRCCS, Policlinico San Matteo,
Università di Pavia, via Taramelli 5, 27100 Pavia, Italy.
2 Divisione di Chirurgia Epatopancreatica, IRCCS, Policlinico San Matteo,
Università di Pavia, 27100 Pavia, Italy.
3 Istituto di Anatomia Patologica, IRCCS, Policlinico San Matteo,
Università di Pavia, 27100 Pavia, Italy.
Received August 2, 2001;
accepted after revision November 20, 2001.
Address correspondence to C. Fìlice.
Introduction
The radiofrequency ablation treatment of secondary tumors, particularly in
the liver, is gaining most of the attention in the field because it may
obviate major surgery [1]. It
is now established that surgical resection of the liver in patients with
colorectal cancer may be curative, with survival rates of 25-40% at 5-year
follow-up and an overall median survival of 33 months
[2]. The need for an
alternative treatment stems mainly from the facts that only 20% of colorectal
cancer patients are suitable for metastasectomy and that the surgery is
associated with considerable perioperative morbidity as well as a mortality
rate of 2-10% [2]. Moreover,
tumor in the liver recurs in 53-68% of patients, and a repeated resection can
be performed in only a minority of such patients. Studies
[1,2,3,4]
have found that radiofrequency tumor ablation, when compared with surgical
resection, entails less invasiveness, markedly reduced treatment costs, and
lower morbidity and mortality rates. In addition, radiofrequency tumor
ablation allows treatment of nonsurgical candidates and the option of
repeating the minimally invasive treatment in the event of local recurrence or
new metastases. However, none of these studies involved the spleen (most
likely because of the reluctance to insert a large-bore needle into a highly
vascularized organ).
We here report our experience in performing radiofrequency ablation of
tumors in the spleen. Our aim was to verify the feasibility of coagulative
necrosis in a colorectal splenic metastasis, this being a very vascularized
lesion in a highly vascularized tissue.
Subject and Methods
In 1999, a right-sided hemicolectomy was performed in a 60-year-old woman
because of colorectal adenocarcinoma. One year later, the patient was
readmitted to our hospital. A CT scan showed a 5-cm mass infiltrating the left
side of the colon, a 2-cm focal lesion in liver segment IV that was contiguous
to the middle hepatic vein, and two nodular subcapsular lesions in the spleen
that measured 1 and 3 cm (Fig.
1A).
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Fig. 1A. —60-year-old woman with hepatic and splenic metastases from
colonic adenocarcinoma. CT scan shows focal lesion (open arrow) in
liver segment IV contiguous to middle hepatic vein and one thermoablated
splenic lesion (solid arrow).
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Informed consent both for surgical intervention and intraoperative
radiofrequency ablation was obtained from the patient. At surgery, the mass in
the colon was found to be an omental metastasis. Omentectomy and ablation of
the mass were performed together with intraoperative radiofrequency ablation
of the hepatic lesion and, before splenectomy, of one of two splenic
lesions.
Intraoperative tumor ablations were done under sonographic guidance using a
linear 7.5-MHz probe (Aloka, Tokyo, Japan). A 15-gauge, 15-cm needle electrode
(LeVeen; Radio Therapeutics, Sunnyvale, CA) was inserted into the center of
the larger splenic lesion and connected to a generator (RF 2000; Radio
Therapeutics) that supplies as much as 100 W of power. Once deployed, the
10-hook electrode array was expanded to a 3.5-cm diameter. Radiofrequency
energy was applied with an initial power setting of 50 W, which is the
standard protocol for hepatic lesions
[5].
To reduce the loss of heat from vascular inflow and to treat the tissue
evenly, the splenic vessels were clamped using the procedure that had
previously been described for the liver
[6]. For performance of
radiofrequency ablation in the spleen, we changed the timing and setting of
radiofrequency power used in the liver protocol, increasing the setting by 10
W at 1-min intervals and lengthening the time before "roll-off" to
approximately one third of that used for hepatic lesions. We then began a
second ablation treatment of the tumor with the setting at 90 W. After 12 min,
the impedance of the treated area increased to more than 200 ohms with a
precipitous decline in power (<10 W), and treatment was terminated. The
splenectomy was performed.
Results
Pathologic comparison between the non-treated and the treated splenic
metastases showed that a central core of necrosis was present in the latter
and almost absent in the former. The diameter of the necrotic zone was about 1
cm. Both lesions showed a peripheral zone of vital tumor, in which the cells
had a picket-fence appearance and the necrosis was without inflammatory cells
(Fig. 1B).
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Fig. 1B. —60-year-old woman with hepatic and splenic metastases from
colonic adenocarcinoma. Photomicrograph of histopathologic specimen of splenic
metastasis of moderately differentiated colorectal adenocarcinoma obtained
after radiofrequency ablation shows central core (single arrow) and
peripheral zone of necrosis (double arrows). In neoplasm, cells have
picket-fence appearance; necrosis is without inflammatory cells. Paraffin
sections were stained with H and E (x10).
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Discussion
Many reasons could explain the poor result: Splenic metastatic disease
lacks several of the pathologic features that actually facilitate
radiofrequency ablation treatment of hepatocellular carcinoma. The latter
arises in a cirrhotic liver and benefits from the so-called oven effect, in
which the fibrous capsule and the surrounding densely fibrotic and poorly
vascularized liver act as retardants to thermal conduction away from the
target lesion and thus maintain optimal heat diffusion in the softer, usually
well-circumscribed tumor nodule
[7]. Generally, metastases are
not encapsulated and tend to infiltrate into the surrounding,
well-vascularized tissue that can function as a heat sink to limit tissue
heating [1,
2]. Another explanation might
be found in our using only H and E staining in the evaluation of the treated
tumor: H and E—stained sections may not accurately reflect thermal
necrosis. The presence of the small foci of necrosis also found in the
untreated lesion raises the question of whether the necrotic effect was due to
the clamping maneuver rather than to the radiofrequency ablation
treatment.
Although we were not able to obtain complete necrosis, we are encouraged by
our initial experience with intraoperative radiofrequency ablation as a
treatment for malignant splenic lesions because it was safe and without
complications. Considering the lack of experience in using radiofrequency
ablation in this organ [5], we
regarded the procedure in our patient as an experiment. Because hepatic
metastases can be successfully treated using this method, we may find that a
longer time and more radiofrequency energy might be needed for splenic
lesions; how much longer a time and how much more energy are still open
questions. Future attempts will probably address these issues. On the other
hand, recent advances in radiofrequency technology provide increased energy
application and larger coagulation volumes, thus allowing optimal treatment of
medium to large metastases of different origins and in different organs and
expanding the indications for use of radiofrequency ablation. In our opinion,
the amount of energy required to treat a colorectal metastasis in the spleen
is much greater than that required to treat the same lesion in the liver or a
hepatocellular carcinoma of the same size.
For this reason, we think that this procedure should be performed only
intraoperatively. Percutaneous puncture of the spleen is feasible
[8], but use of a needle
electrode for radiofrequency ablation in the spleen is problematic because it
requires the puncture of a highly vascularized tissue with a large-bore needle
for a long period (20 min at the shortest), with no way to reduce the blood
flow or monitor possible bleeding. Moreover, the high vascularization of the
spleen produces extremely high intraabdominal temperature, with the risk of
thermal lesions of the adjacent viscera. This problem is also likely to be
encountered using the laparoscopic approach, which has become the first choice
for intraoperative thermal ablation of liver tumors. Finally, clamping of
splenic hilus, corresponding to the Pringle maneuver for the liver, is not
always a safe procedure for anatomic reasons.
In conclusion, radiofrequency ablation could become an effective technique
for treating splenic metastases without splenectomy. The true role of this
method still remains to be determined, and more studies are needed so that the
results of different options may be compared.
References
-
de Baere T, Elias D, Dromain C, et al. Radiofrequency ablation of
100 hepatic metastases with a mean follow-up of more than 1 year.
AJR
2000;175:1619
-1625[Abstract/Free Full Text]
-
Solbiati L, Ierace T, Tonolini M, Osti V, Cova L. Radiofrequency
thermal ablation of hepatic metastases. Eur J
Ultrasound 2001;13:149
-158[Medline]
-
McGahan J, Dodd G. Radiofrequency ablation of the liver: current
status. AJR
2001;176:3
-16[Free Full Text]
-
Curley S, Izzo F, Delrio P, et al. Radiofrequency ablation of
unresectable primary and metastatic hepatic malignancies: results in 123
patients. Ann Surg
1999;230:1
-8[Medline]
-
Goldberg SN, Gazelle GS, Mueller PR. Thermal ablation therapy for
focal malignancy: a unified approach to underlying principles, techniques, and
diagnostic imaging guidance. AJR
2000;174:323
-331[Free Full Text]
-
Rossi S, Garbagnati F, Lencioni R, et al. Percutaneous
radio-frequency thermal ablation of nonresectable hepatocellular carcinoma
after occlusion of tumor blood supply. Radiology
2000;217:119
-126[Abstract/Free Full Text]
-
Livraghi T, Lazzaroni S, Meloni F. Radiofrequency thermal ablation
of hepatocellular carcinoma. Eur J Ultrasound
2001;13:159
-166[Medline]
-
Civardi G, Vallisa D, Berte, et al. Ultrasoundguided fine needle
biopsy of the spleen: high clinical efficacy and low risk in a multicenter
Italian study. Am J Hematol
2001;67:93
-99[Medline]
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Introduction
Subject and Methods
