A 74-year-old woman diagnosed with a low rectal tumor and multiple synchronous small right liver metastases located within segments VI, VII and VIII. The patient received neoadjuvant chemoradiation therapy yielding an apparent complete response in the rectum but residual disease in the liver. She proceeded to a right hepatectomy where an R0 resection was obtained with an uncomplicated recovery. Resection of any identifiable primary rectal disease will subsequently be evaluated in follow up.
Case Discussion:
DR PRIMROSE: This was a patient with a low rectal cancer and synchronous liver metastasis. After chemoradiation therapy, the response was good, so it was not entirely clear if there would be any detectable disease in the rectum at the time of surgery. This is something that happens quite often with modern chemotherapy schedules and chemoradiation therapy. She had a complete response in the rectum, but not in the liver. She still has liver metastases. So, in this situation, the residual disease in the liver will be resected, and the colorectal surgeon will reexamine the patient, acquire more imaging and see what happens to the rectum.
The reason for perhaps equivocating about resection of the rectum in this case is that it is a low rectal tumor. She would need an abdominal peroneal resection and a permanent colostomy. I believe that the intention was to wait and see whether the complete response in the rectum actually remains so. Regrettably in most cases, the patient will need to have further surgery, because the disease comes back in rectal cancer.
If you observe a complete response in the liver within a circumscribed area, for instance all in the right lobe, we would remove it and submit it to the pathologist. In most cases, they will find nests of tumor within the liver. The difficult problem for liver surgeons is where bilateral disease is present with awkwardly placed metastases and they disappear with chemotherapy. Whereas before chemotherapy, you could have located them and excised them, but now there is nothing to see — that is the problem. If we’re in that situation, we do the best we can. We’ll take out the areas that contained disease. We may leave some areas that also contained disease, because they’re awkward to resect. So sometimes, at best, the oncologists don’t fare particularly well in reducing the size of liver metastases before surgery, because if you make them undetectable, it makes the surgeon’s job much more difficult. This is all about working closely with your medical oncologist. Often operating before the patient has achieved a maximum response is the easiest way of removing the disease.
The definition of a good radiologic margin is controversial. Given the choice, we would all prefer to have a centimeter liver clear of any metastatic deposit on our excision specimen — that would be the ideal, but often that’s not possible. I think current thinking is that any margin is probably acceptable, if you can’t do any better, provided you remove the tumor. Even if it’s a millimeter or less, it’s probably a reasonable thing to perform, because not all patients will develop local recurrence. Many of us use an ultrasound dissector during liver surgery, which probably produces a margin of a millimeter or so, in addition to what the pathologist receives. So, when we talk about margins, we’re not talking always about the same thing.
In terms of the anatomy, we obviously are concerned about the inflow and the venous drainage, so the bile duct usually doesn’t matter so much, because you can replace it. Sometimes you can resect and reconstruct the portal vein. The hepatic artery is much more difficult to work around. Margins on the major vascular structures are what cause us the most concern. Most of us would say that any margin is better than nothing — even if you can’t get a centimeter, it’s probably still worth performing.
It is difficult to predict prognosis according to the time from adjuvant chemotherapy to recurrence. I think the difficultly in a lot of situations lies in the quality of the imaging that was done up front. If you obtain high-quality imaging on these patients, in all probability you’ll detect that the disease has always been synchronous in presentation. It’s just that a better scanner will show you more than a poor scan. I think up front you might say, “Well, a patient who gets disease that quickly after adjuvant chemotherapy is likely to have worse disease.” That may be true, but I don’t think we can prove that, and it certainly does not affect my decision-making process in any way about offering them surgery.
The majority of patients who have undergone liver surgery will still relapse. If relapse occurs, it may be amenable to further chemotherapy and further surgical treatment, so relapse does not automatically mean that the patient is untreatable. I tell every patient that that one percent of patients die from the procedure. We warn them about the possibility of perioperative mortality also.
