Resectability Criteria

Decision to resect highly distributed liver lesions

Commentator: RENÉ ADAM, MD

Comment:

The decision to resect is partially based on whether the patient responds to chemotherapy. If the patient does not respond to the first choice of chemotherapy, the best option is to switch to another regimen. The priority is to use a systemic treatment because the disease is systemic.

Acceptable size of remnant liver

Commentator: RENÉ ADAM, MD

Comment:

Too small is defined as less than 30 percent of the total liver parenchyma when the patient has not received intensive chemotherapy. When using intensive chemotherapy, too small is defined as a remnant liver less than 40 percent.

Determination of resectable disease

Commentator: MICHAEL CHOTI, MD

Comment:

Resectable disease can be defined as a tumor that is located in a part of the liver that can be completely resected while leaving sufficient liver behind. The factors that contribute to resectability include the extent of disease, the extent of tumor involvement in the liver, the tumor locations relative to the main hepatic branches, the main portal pedicles and the hepatic venous drainage. We base the decision about whether a tumor is resectable by which branches need to be divided or taken out to remove the tumor. The other concern is whether sufficient residual liver will be left behind if a large part of the liver must be removed. Will there be adequate inflow to the remaining liver? Adequate hepatic artery flow, portal vein flow and bile duct flow into the remnant liver? Is there adequate venous drainage in the proposed remnant liver? Is there adequate volume in the remnant liver, and how healthy is the proposed remnant liver? Is it a healthy piece of liver or is it a damaged liver? For example, in a patient with cirrhosis or hepatitis, the liver is unhealthy, and we cannot remove much of the liver at all. In contrast, if someone has a healthy liver with good inflow and good outflow, we can remove up to 80 percent of the liver volume. The remaining 20 percent will regenerate nicely. However, in a patient who is a bit obese, the patient may have obesity-related damage to the liver referred to as steatosis. In that situation, the liver is a little less healthy. Also, the liver can be stressed after treatment with a fair amount of chemotherapy.

There are four categories of resectability: straightforward resectable disease, resectable disease with some nuances, unresectable but potentially convertible with chemotherapy and unresectable and unlikely to convert. At times, the optimal approach is not obvious. We can conduct volumetrics to determine whether the remnant liver will be of sufficient volume by using a formula to calculate the residual liver volume on CT scan. Another option would be to perform a procedure called PVE, in which we embolize the vein to the right half of the liver causing the right half of the liver to shrink a little bit and causing the left part — the part that will remain — to grow and regenerate in advance of the surgery. So, portal vein embolization could be used in patients who don’t need chemotherapy to shrink their tumors but need the liver prepared to become resectable.

Estimation of postsurgical hepatic reserve

Commentator: MICHAEL CHOTI, MD

Comment:

Even in the healthiest liver, the data suggest that you need at least a 20-percent remnant. The radiologist can calculate the volume of the remnant liver by dividing the total liver volume by the measured remnant volume. Instead of measuring liver volume, we estimate the total liver volume based on height and weight.

Determining the extent and resectability of disease

Commentator: NICHOLAS PETRELLI, MD

Comment:

First, we perform an exploratory celiotomy — also called a laparotomy — to explore the abdomen to make sure no extrahepatic disease is present. If the patient has extrahepatic disease, then “the cow’s already out of the barn” and the resection is abandoned in favor of systemic therapy. After extrahepatic disease is ruled out, you palpate the liver and examine all the organs. You palpate the liver, inspect the liver, mobilize the liver and perform an intraoperative ultrasound to make sure that no other lesions are in the liver. You examine the lesion’s relationship to the vessels. If everything is as expected, you proceed with the resection.

Estimating residual hepatic function after surgery

Commentator: NICHOLAS PETRELLI, MD

Comment:

In general, you can remove about 80 percent of the liver. The liver is the only organ in the body that will grow back to approximately its normal size. However, the 20 percent that we leave behind must be normal liver. If a patient has cirrhosis or has had previous chemotherapy, that 20 percent will not be enough. You can obtain volumetric measurements based upon the amount of liver that you’re taking out to calculate the amount of functional liver that will remain. The threshold for which you use volumetric studies varies depending on the disease characteristics and whether or not associated disease is present in the liver.

Resection of unilobar versus bilobar disease

Commentator: JOHN PRIMROSE, MD

Comment:

I think plenty of evidence now exists that both unilateral and bilateral disease are resectable. Clearly, bilobar disease is sometimes more difficult to resect completely, because there may be an insufficient number of remaining segments for adequate liver function, but we have techniques to deal with this. The two that we commonly use are PVE of the right portal vein — to encourage hypertrophy on the left — and staged resection. For instance, in the first surgery, you might remove the disease from the left liver, allow a few weeks for recovery and then perform a right hepatectomy. That’s a safe strategy for managing these patients, and it’s worked well for us in many situations.

Evaluating resectability of lung metastases

Commentator: STEVEN CURLEY, MD

Comment:

The patient had localized nodal metastases, and published data demonstrate a potential survival benefit for patients with two sites of metastatic disease from colorectal cancer — in this case, liver and lung — that can both be resected. Studies have also been published on patients who present with lung as their only site of metastatic disease and, similar to patients who have hepatic metastases, if the lung metastases can be resected — particularly in concert with either neoadjuvant or adjuvant chemotherapy — they have a five-year survival that’s in excess of 30 percent, and in some series, it is in excess of 40 percent at five years. Unfortunately, the lung data are identical to that of liver metastases in that there have been no randomized prospective trials, but rather multi-institution or single-institution studies that have treated a large volume of patients.

Impact of the surgeon’s experience on the potential curability of metastases

Commentator: DANIEL HALLER, MD

Comment:

In cases where a hepatic metastasis abuts a major artery from the aorta, you need an experienced radiologist and surgeon, in addition to good imaging. Not that many years ago, if you couldn’t see a rim of normal tissue, these cases would have been considered incurable, even in major centers. Unfortunately, even now in many centers some patients are not referred for consideration of surgery who should be. Today in such a case, if the surgeon said “No” to surgery, then I might send the images to a more experienced surgeon. Not all surgeons have equal experience.

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