NEW YORKA diagnosis of advanced colon cancer may lead some physicians to abandon treatment with curative intent, but John Macdonald, MD, insists that they should be more optimistic and aggressive.
Dr. Macdonald, professor of medicine and chief of the Gastrointestinal Oncology Service at the Comprehensive Cancer Center of St. Vincents Hospital Center, New York, New York, spoke to colon cancer patients at a teleconference sponsored by Cancer Care, Inc.
One of the things we are interested in at cancer centers is to educate both patients and doctors that it is important not to give up, he said. It may be that the best thing to do is palliative therapyor it may be better to get patients into the hands of people doing aggressive research who will try for a cure. Someone will always be the first person to respond to a therapysomeone in 1939 was the first to be cured of an infection with penicillin.
Up until 5 years ago, there was essentially only one drug that could be used effectively in colon cancer, fluorouracil(Drug information on fluorouracil) (5-FU). Fluorouracil is still standard of care, and many patients get it, but there are other drugs coming along, recently approved or in the process of being approved, that are of real interest in the treatment of advanced colon cancer and may have some advantages over fluorouracil, Dr. Macdonald said.
New Drugs, New Hope
One such drug is irinotecan(Drug information on irinotecan) (Camptosar). It has been shown to have activity in colon cancer even when fluorouracil does not work, he said. A European study in which patients were randomly allocated either to irinotecan or to supportive care alone showed that treatment with irinotecan nearly doubled survival rates and also led to a decrease in symptoms, he noted.
Other drugs are being explored that directly target the molecular differences between tumor cells and normal cells, Dr. Macdonald said. Anti-ras drugs are targeted against the ras oncogene important in gastrointestinal cancers and colon cancer. An antibody against colon-cancer-associated antigens is being tested to prevent tumor recurrence.
Expert liver surgeons are offering more hope to colon cancer patients with liver metastases. In the past, he said, when patients disease would recur in the liver, many doctors, internists, gastroenterologists, and surgeons would say there is nothing else to do. They would give them a little chemotherapy, but no cure. But today, he said, frequently if the patient has three or fewer liver tumors, the lesions can be surgically removed.
We have quite good evidence that if an otherwise healthy patient with liver recurrence is operated on by an experienced liver surgeon, as many as 30% of patients can be rendered disease free, Dr. Macdonald said. Further, he said, adding chemotherapy after tumor removal, sometimes by injection into an artery leading into the liver, is under study in clinical trials and has shown good initial results.
New oral variations of fluorouracil such as UFT (Tegafur, Ftorafur) are also being tested. If these drugs are shown to be as active as 5-FU in the adjuvant and advanced setting, they could eliminate the need for needles, injections, and intravenous catheters. It will be much easier on patients, and the toxicity patterns will be milder. We dont expect these drugs will have a major curative result, but they will improve quality of life, Dr. Macdonald told Oncology News International. These innovative ways to treat cancer will change the way physicians and patients view the rigors of chemotherapy in advanced disease, he concluded.