It might be worth you looking at d-limonene which is an essential oil from fruit peel. In some studies it showed some promise but with one trial which finished in March 2011 the results were never published which seems a bit suspicious to me. Maybe drug companies paid for the results to be buried for fear that it might affect the sales of their toxic chemo drugs.
It does seem to be work better as a preventive but might prove useful to you if it helps prevent metastasis. It's not expensive, a large bottle costs very little. I have some myself as it is supposed to help stimulate healing of the digestive system as well as help prevent colon cancer among many others.