I'm interrupting the gallbladder series for a moment, at the news of Tony Snow's discovered metatstatic colon cancer in his liver. As I said about Elizabeth Edwards a couple of posts back, when famous people get sick, it's an opportunity to learn. If nothing else.
In the case of colon cancer which has spread to the liver, the outlook is not good. On average, survival is in the range of six months (as with all cancers, there are variations in both directions). There are exceptional circumstances, for instance when it appears that only one tumor nodule is growing in the liver, in which case removing it and giving chemotherapy may prolong life. Unfortunately that's rare: in most cases when it's discovered, it's widespread. Response to drugs is usually brief. Some data suggest improved response when the drugs are infused directly into the artery to the liver (in the linked diagram, the images are of experiments in rats. The one on the right is sort of like what happens in humans).
In my practice I had one patient who defied the odds so dramatically that I hesitated to mention him when I talked to others in whom I'd discovered the disease. My desire was to be candid and realistic, but, at least early on, to encourage a trial of treatment. Compared to some, the drugs used for liver metastases of colon cancer are usually well-tolerated. Response is not great overall, but once in a while.... So I'd generally suggest giving it a try, but I didn't want to raise expectations inappropriately.
My patient was in his forties and feeling healthy until he started noticing blood in his stools. It wasn't until he started having frequent cramps that he decided to see his doc, at which point, unsurprisingly, he was found to have a large tumor in his sigmoid colon. His CEA (a blood test related to colon cancer, the usefulness of which in terms of diagnosis and treatment remains controversial) was the highest I've ever seen, consistent with the amount of tumor in his liver. Nevertheless, to prevent impending obstruction, and to stop his bleeding, I operated and removed the tumor. After rapid recovery, I sent him to an oncologist who began chemotherapy. I didn't see the man again at that point, although I got the occasional office note copied from the oncologist, noting dramatic drop in the CEA levels. Eventually the man dropped out of my consciousness.
Until about eight years later, when he accompanied his wife on her appointment to see me for gallbladder surgery (see, maybe I'm not really interrupting the series after all). He looked like a million bucks. Is it wrong to act surprised to see someone alive? "Wow!" I blurted. "How great to see you! Look at you... [I figured you'd be dead by now.]"
In such a dramatic and nearly singular situation, you have to wonder if it was the drugs or if somehow his tumor had mutated in such a way as to allow his immune system to recognize and destroy it. There's no way to know. But, wanting to present a glimmer of hope in terrible circumstances, I did mention this man to subsequent patients. Until there's evidence to the contrary, I'd say, it makes sense to hope for the best while preparing for the worst. That's what I'd tell Tony Snow.
Addendum 3/28: Orac has a post on the subject, in which he says with the addition of anti-blood-vessel-forming therapy the median survival of liver metastases from colon cancer is 20 months, while five-year survival remains uncommon. I'd take his word over mine; he's active in the field, I'm an old guy. Ironically, I've been asked to move my blog to Scienceblogs, where his is. I'm debating with myself if I'm enough of a science guy to belong in the club. Maybe not.