A persistent rise in the carcinoembryonic antigen (CEA) level measured every 2 to 3 months during the postoperative years following resection of a colorectal malignancy is an indication for a thorough search for a possible recurrence. The original operation and pathologic reports are reviewed because they may provide a clue as to where the recurrence is located. However, the liver is the chief organ to be investigated by imaging scans (CT, MRI, PET-CT), abdominal echograms, and liver function studies as well as a complete survey of the colorectal system by colonoscopy. Evidence of metastases to the lungs or diffuse involvement of the abdomen or bone generally contraindicates surgical intervention, but local excision is usually considered in a good risk patient with a definite steady increase in the CEA level. Further, a hepatic lobectomy may be considered for a metastasis too large for local excision. Radio immuno-guided detection of recurrent malignancy may be useful in localizing metastasis which otherwise would be missed as well as providing evidence of complete resection of the tumor. The 5-year survival rates following the removal of hepatic metastases tend to be encouraging. The patient should be fully informed of the reasons for the “second look” exploration as well as the uncertainty of being cured of recurrence of malignancy.
Multivitamins and adequate caloric intake are urged during the days of preoperative investigation. Antibiotics are given.
A general intratracheal anesthetic is given. Catheters are placed in both arms for replacement of fluid and blood products if required.
The patient is placed supine on the operating table in a slightly reverse Trendelenburg position.
The skin is prepared over the chest and abdomen down to the pubis.
An extended or bilateral subcostal incision can provide excellent exposure. Alternatively a liberal midline incision beginning over the xiphoid may be used.
The peritoneum, the small and large intestines, the cul de sac, mesentery, and omentum are all inspected for evidence of metastases. The major concern will be the liver, especially if preoperative studies indicate probable liver involvement. If only one or two very small metastases are found in readily accessible locations, they can be excised or destroyed by cauterization. Diffuse multiple metastases should be considered to contraindicate extensive attempts at surgical excision of many sites of recurrence.
The liver is carefully inspected and palpated bimanually. In addition, the use of hand-held intraoperative ultrasound is very useful in the search for deep metastases. Sufficient mobilization of the liver is advisable to visualize the dome and posterior aspects of the liver. The falciform and triangular ligaments are divided to ensure direct vision of all aspects of the liver. Fixation of the liver with tumor invading into the diaphragm posteriorly is a relative contraindication for excision.
The size and location of the metastases as well as the age and general condition of the patient are factors to be considered in determining whether local excision or lobectomy are to be performed. A metastasis tends to be spherical but usually is not so deep as it is wide. Local excision is usually performed when more than one metastatic nodule is present in the liver or both lobes are involved, and in the presence of a recurrence after a previous resection of more than one or more metastases.
When the metastatic nodule is near the margin of the left lobe of the liver, a wedge resection is easily performed (Figure 1). A safety zone of at least 1 or preferably 2 cm is outlined with an electrocautery around the metastatic nodule, since at least 1 cm of normal liver should be excised with the lesion.
Distal to the cautery line and parallel to it, a series of deeply placed mattress sutures of catgut on slightly curved large thin needles are placed in the liver tissue to provide hemostasis (Figure 2). These catgut sutures are carefully tied to compress the liver tissue without lacerating the surface of the liver.
One or more traction sutures (A) may be placed in the safety zone between the tumor and the line of compression sutures. The traction sutures should never be placed through the tumor, since seeding may take place. Such sutures are valuable in lifting up the tumor as the dissection progresses (Figure 3). Traction on these sutures helps in keeping a safe distance from the metastasis as the tumor nodule is retracted upward. Every precaution is taken to ensure a safe zone of normal liver tissue beyond the neoplasm, especially in the deepest portion of the resection. The electrocautery or laser may be used for the division of the liver tissue as well as to control bleeding. Many surgeons use the Cavitron Ultrasonic Surgical Aspirator (CUSA) ultrasonic instrument for dissection, while others find the Argon beam electrocoagulator very useful for obtaining hemostasis.
Any visible vessels or bile ducts may be clipped (Figure 4). However, most liver surgeons prefer individual ligation of vessels and ducts. The pathologist must evaluate the completeness of the resection before closure.
Sometimes several metastases of various sizes may be excised in a similar fashion. Some prefer to pack the cavity left by the excision for a few minutes with Surgicel gauze saturated with a chemotherapeutic chemical. Blood loss is rarely a troublesome factor in the excision of liver metastases, unless the lesion is located rather deep and near a sizable blood vessel in an unusual location. The risk of excising such lesions must be carefully weighed against the potential gain of their removal. In such instances, anatomic resection with pedicle control may be a safer option.
If the field is dry, drainage is not necessary (Figure 5), otherwise, Silastic closed-system suction drains are inserted in the area. If bile is noted to escape into the liver tissue, an effort should be made to ligate the area of drainage and consider closed suction drainage.
When the margins of the metastasis are questionable, additional liver tissue is excised for study by the pathologist.
Patients with proven metastases should be considered candidates for chemotherapy. The CEA levels are measured every two or three months, and the patient is surveyed for evidence of other recurrences. Measurements should be continued indefinitely, although the interval between tests can be lengthened after several years if the CEA level and CT scans as well as other evaluation procedures remain within a normal range.