Dr. Sardi and colleagues lay out, in a clear and concise fashion, current alternatives for the management of primary and metastatic liver tumors. Their emphasis on "high-value" treatments is crucial. In this group of patients, unnecessary treatments not only are costly in terms of dollars but also reduce the quality of the short life remaining in patients with unresectable disease.
This review of the state of the art describes no exciting new therapies because no promising treatment options have emerged recently. Nevertheless, a review of the management of primary and metastatic liver tumors is very timely. Even though new management strategies are absent, the ones currently being employed by meticulous practitioners produce far superior results than were achieved in the past. This is the result of many small changes that, as a composite, are making a definite difference in the benefits that accompany the treatment of liver tumors.
Large Differences from Small Changes
Sardi et al enumerate several of these important small changes that have led to big differences. First, radiologic techniques are far superior now than they were in previous years. Our ability to detect disease at distant sites has greatly improved. Lung metastases as small as 3 mm in size are routinely detected by CT. Other metastatic lesions as small as 5 mm that had previously escaped detection are now routinely imaged by MRI or spiral CT with contrast infusion. This means that fewer patients are left with persistent disease after the surgeon's best efforts to achieve a complete resection. Radiologic "stage migration" probably does more to improve the results of surgery than any other single management routine.
One caveat in this regard remains: The hepatic lymph nodes are a difficult area for the radiologist to image. However, being aware of this "radiologic blind spot," surgeons biopsy the hepatic lymph nodes intraoperatively as part of the abdominal exploration so that patients with metastatic disease do not undergo a liver resection that is not indicated .
Second, resection of liver tumors nowadays is associated with low mortality (< 5%) and low morbidity (< 10%) . In addition, the survival rate is greatly improved, even doubled, over that reported by Hughes and colleagues  in 1986. Stage migration is important, but improved margins of excision, less intraoperative disruption of resected specimens, and chemotherapy may all contribute to better survival. This improvement in survivorship is evident even though resection of two to four metastases (as opposed to a single metastasis) is commonplace.
Tumor Markers of Great Value
Tumor markers also are of great value in this population of patients, especially those with colorectal metastases to the liver. Serial carcinoembryonic antigen (CEA) assays or CA 19-9 assays after a colon resection reveal liver metastases in approximately 40% of patients, and these are isolated in approximately 10%. Now, smaller isolated lesions that are confined to the liver are seen, rather than symptomatic lesions that themselves have caused metastases. Tumor marker follow-up of patients after a potentially curative resection of colorectal cancer, leading to subsequent curative liver resection, is an extremely important part of postoperative management of large bowel cancer .
Tumor marker follow-up not only is necessary after colon resection but also is of value in monitoring patients after liver resection for primary and metastatic liver tumors. A second rise in CEA during serial assessment of this marker may lead to the identification of an additional liver lesion. The same may be true of alpha-fetoprotein follow-up after resection of a hepatoma. The surgical value of second liver resections is the same as, if not better than, that of resection of an initial liver metastasis [5-7].
Conclusions regarding the selection of patients for liver resection with colorectal metastases have been greatly clarified. However, after all the data have been gathered, the selection criteria remain extremely broad. Patients who have a reasonable morbidity and mortality and who can be rendered clinically disease free by liver resection should be given the benefit of this treatment modality.
Proliferation of Nonresection Techniques
Finally, Dr. Sardi and colleagues call our attention to the proliferation of nonresection techniques for tumor ablation within the liver. Cryosurgery, chemoembolization, percutaneous ethanol injection, and hepatic artery infusion chemotherapy are but a few of the liver-specific treatments. In my opinion, these techniques should be viewed as complementary rather than competitive. Together, they can result in a more complete treatment than was possible in the past, and can make the concept of liver cytoreduction a reality.8 For example, the major problem with the infusion techniques has been local recurrence at the site of large tumors. Therapy such as cryosurgery can ablate nodules and prevent this breakthrough in response to chemotherapy. Combinations of these treatments that result in little or no morbidity and no mortality are necessary in the next decade of research on hepatic tumor