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Surgical Management of Pancreatic Cancer

Surgical Management of Pancreatic Cancer

ABSTRACT: Pancreatic cancer is the fifth leading cause of cancer death in the United States, with an overall survival rate of 3%. Unfortunately, only a minority of patients present with localized disease amenable to surgical resection. Over the past 20 years, improvements in operative and perioperative management have led to a decrease in operative mortality, shorter hospital stay, and overall 5-year survival of approximately 20% in patients undergoing pancreaticoduodenectomy. Despite advances in nonoperative palliation, surgery continues to play an important role in the management of patients with locally advanced, unresectable pancreatic cancer. [ONCOLOGY 16:725-743, 2002]

Pancreatic cancer is the fifth leading cause of cancer
mortality in the United States and has the lowest survival of any cancer.[1]
Roughly 15% to 20% of patients with pancreatic cancer present with disease
localized to the pancreas. In these patients, surgical resection offers the best
option for prolonging life and the only option for long-term survival. Although
once associated with high operative morbidity and mortality, pancreatic
resection can now be performed safely at many centers. This review will focus on
the preoperative assessment, perioperative management, and outcome in the subset
of patients with potentially resectable pancreatic cancer.

Preoperative Staging and Assessment of Resectability

Spiral Computed Tomography

Spiral computed tomography (CT) scanning is the primary imaging study for
patients with suspected pancreatic cancer. This technique offers both a
sensitive means of diagnosing the disease as well as a cost-effective,
noninvasive means of staging and determining resectability. Dual-phase spiral CT
scanning is preferred, with an arterial phase 20 to 25 seconds after intravenous
contrast injection using 3- to 4-mm collimation followed by venous phase 60 to
70 seconds after contrast injection using 5- to 7-mm collimation.[2] CT evidence
of a pancreatic mass, the local extent of the tumor, and the presence of
metastatic disease are all important in determining whether a patient with
suspected pancreatic cancer is a candidate for surgery (Figure
1
).

Pancreatic cancer usually appears as a hypodense mass on spiral CT. Overall,
the sensitivity of dual-phase spiral CT in detecting pancreatic cancer ranges
from 85% to 95%.[3] The technique is less sensitive for small lesions (< 15
mm), but sensitivity approaches 100% for larger lesions (> 15 mm).[4]

Spiral CT is also accurate in predicting resectability based on the proximity
of the primary tumor to major vascular structures, and CT evidence of vascular
involvement correlates with overall survival in patients with pancreatic
cancer.[5-7] Preservation of the fat planes around major vessels suggests lack
of tumor invasion and is consistent with resectability.[5,6]

Lu et al examined 48 major vessels in 25 patients with pancreatic cancer
using both spiral CT and operative dissection to determine resectability.[6]
Tumor contiguity to major vessels (portal vein, superior mesenteric vein or
artery, hepatic artery, and celiac axis)—ie, invasion of less than 25% of the
vessel circumference—was associated with resectability in all cases.[6]
Circumferential contiguity exceeding 50% precluded resection in over 95% of
cases. The presence of periportal collaterals or dilated small peripancreatic
veins suggests portal vein occlusion and is also a reliable sign of
unresectability.[8] Spiral CT angiography uses axial images to generate
three-dimensional (3D) vascular images similar to those produced with
traditional angiography.[5]

Spiral CT is not sensitive in detecting small hepatic metastases, and lesions
smaller than 1 cm are commonly missed. In addition, the presence of enlarged
peripancreatic lymph nodes on CT scans does not correlate with the presence of
metastatic cancer or survival.[7] Enlarged lymph nodes are often benign, and
metastatic cancer is commonly present in normal-sized lymph nodes. Therefore,
the presence of an enlarged lymph node should not discourage surgical referral.
Small peritoneal metastases are also commonly missed by CT scans in the absence
of ascites.[2]

Other Imaging Studies

Magnetic Resonance Imaging

Magnetic resonance imaging (MRI) with
contrast administration provides comparable information on tumor extent and
vascular or hepatic involvement to that obtained with spiral CT.[2]
Cholangiopancreatography with MRI produces images of the biliary tract and
pancreatic duct of similar diagnostic quality to endoscopic
cholangiopancreatography.[9] MRI is useful in patients with significant
allergies to contrast or for cases in which the CT scan does not demonstrate a
mass in a patient with suspected pancreatic cancer.

Endoscopic Ultrasound

Endoscopic ultrasound is as sensitive as
dual-phase spiral CT in detecting pancreatic masses and can be used to
accurately assess vascular involvement.[3] Endoscopic ultrasound-guided
fine-needle aspiration is also a safe method of obtaining a tissue diagnosis
with less theoretical risk of tumor cell implantation than that associated with
percutaneous biopsy.[3] However, routine use of this invasive diagnostic test is
unwarranted; its use should be limited to patients with equivocal CT scan
findings or for obtaining a tissue diagnosis in patients with unresectable
tumors.

Positron-Emission Tomography

Positron-emission tomography is a
newer modality that uses the increased metabolism of labeled glucose by
pancreatic cancer cells to form images.[2] This technique may provide a
sensitive means of detecting hepatic, nodal, or peritoneal metastases, and may
also be able to differentiate benign from malignant pancreatic masses.

Endoscopic Cholangiopancreatography

Endoscopic retrograde
cholangiopancreatography is very sensitive in diagnosing ductal adenocarcinoma
of the pancreas. The finding of a long irregular stricture in an otherwise
normal pancreatic duct is virtually pathognomonic in the appropriate clinical
setting.[2] However, given the diagnostic accuracy of dual-phase spiral CT, this
study is rarely necessary[2] and should be reserved for patients in whom the
diagnosis of pancreatic cancer is not straightforward.

Laparoscopic Staging

Staging laparoscopy and laparoscopic ultrasound have been used to compensate
for the low sensitivity of CT in detecting small peritoneal and hepatic
metastases.[3] Appropriate laparoscopy may avoid a nontherapeutic laparotomy in
patients with limited survival due to unresectable pancreatic cancer. Several
studies have examined the role of laparoscopic staging in patients with
periampullary malignancies thought to be resectable after conventional imaging
studies.[10-12]

Callery et al evaluated 50 patients with hepatobiliary and pancreatic
malignancies using laparoscopy and laparoscopic ultrasound.[10] Of these
patients, 44% had either metastases or vascular invasion—missed by dynamic CT
scanning—that precluded curative resection. In a larger series of 203 patients
with periampullary cancer, Nieveen van Dijkum et al identified metastatic
disease in only 15% of patients using laparoscopic staging.[11]

As CT technology improves, the yield of laparoscopic staging may be
decreasing. Using helical CT scans and 3D CT angiography, Saldinger et al graded
vascular involvement in 52 patients with pancreatic cancer.[5] Of 35 patients
with minimal or no vascular involvement, 94% were resectable.[5] The incidence
of metastases or vascular involvement precluding resection increased
dramatically with greater vascular involvement seen on CT.

Laparoscopic ultrasound appears to provide little additional information to
that obtained with high-quality dual-phase spiral CT.[5] Thus, laparoscopy
should be used selectively in patients at higher risk of having peritoneal or
small hepatic metastases (lesions in body and tail of pancreas, grade 2 or 3
vascular involvement, ascites, larger tumors, or other findings suspicious for
unresectability on CT).[3,5] Laparoscopy is not warranted in patients who would
benefit from palliative surgery if unresectable.

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