Fashionbuyer,
My understanding is that Avastin shrinks existing tumors and slows their growth. Then, sadly, the body becomes immune to Avastin's benefits and this chemo stops working. Tolerance to Avastin varies from person to person. For example, in my husband's case, I've read that Avastin on average, will slow the growth of secondary peritoneal mets by 7 months before the cancer progresses. But there is one woman being treated by my husband's oncologist, who has similar secondary colorectal mets to her peritoneum, and she's been on Avastin off-and-on for two years now and she's doing OK. So, much depends on individual's responses to this particular chemo agent. I'm hoping Avastin will work a very long time for my husband (who is currently NED and it's just about 7 months into his journey).
It is also my understanding from recent medical studies, that potentially curative outcomes have achieved when secondary colorectal mets to the liver can be resected via surgery -- typically when the tumors have "shrunk" to a size that makes the patient a candidate for surgical procedures. In short, from what I've been reading, curative results can happen in some Stage IV cancer patients. If your father chooses to go on Avastin, and if he can tolerate it, this chemotherapy might be able to shrink his liver tumors to a size where they can be potentially resected via non-invasive methods, like "cyberknife" for example, which is a targeted radiation beam honed straight in on the tumors, or radio frequency ablation therapy, which I believe can work on smaller size tumors - or even by more tradition surgical methods where a portion of the liver is removed.
At minimum, for most patients, Avastin will slow the growth of the cancer. Avastin (as a therapy combined with other chemotherapeutic agents) is not considered a curative modality, but can oftentimes prolong life with good quality of life outcomes.
Paula Jean