Avastin Slows Colon Cancer Growth

An anticancer drug that starves tumors of a blood supply can help delay progression in patients with advanced colon cancer.

In a study of more than 1,400 patients, those who took the drug Avastin in addition to standard chemotherapy remained alive without worsening of their disease about one-and-one-half months longer than those with chemotherapy alone, says researcher Leonard B. Saltz, MD, a member of the Gastrointestinal Oncology Service at Memorial Sloan-Kettering Cancer Center in New York City.

While an extra month or two might not sound like much, the tens of thousands of people whose colon cancer has started to spread throughout their body face a fairly bleak outlook.

In the study, those given standard chemotherapy alone remained progression-free for an average of only eight months.

In contrast, cancer didn't progress for nearly nine-and-a-half months when Avastin was added to the treatment.

"Avastin controls the cancer longer," Saltz tells WebMD. "It's a modest advance, but an advance."

Neal J. Meropol, MD, director of the Gastrointestinal Cancer Program at Fox Chase Cancer Center in Philadelphia, says many doctors are already offering the drug to patients with advanced disease.

"The study validates the use of Avastin as a component of front-line therapy with [standard] chemotherapy for metastatic colon cancer," he tells WebMD.

Cancer's Comeback Delayed

The study, one of the largest ever conducted in people with metastatic colorectal cancer, was presented here at the 2007 Gastrointestinal Cancer Symposium.

All study participants were given one of two standard chemotherapy treatments, either Xeloda plus Eloxatin -- or a combination of 5-FU, leucovorin, and Eloxatin.

Then, half were also given Avastin.

Saltz's group is still analyzing the data to determine whether Avastin actually extends lives.

He expects to present those findings in June at the annual meeting of the American Society of Clinical Oncology.

Drug Cuts off Blood Supply

Avastin -- which is also approved to treat advanced lung cancer -- was the first of a new kind of cancer therapies that work by cutting off the blood to a tumor.

This starves the tumor, slowing or even stopping tumor growth in its tracks.

Side effects in the study were due primarily to the Eloxatin-based chemotherapy and included pain, numbness and tingling, lowered resistance to infection, fatigue, and diarrhea.

While other studies have linked Avastin to an increased risk of potentially fatal blood clots, there was no difference in the number of people who developed clots in the Avastin and non-Avastin-groups.

Nevertheless, the drug should be avoided by people with a history of blood clots and those who have suffered a heart attack or stroke, Saltz says.

SOURCES: 2007 Gastrointestinal Cancer Symposium, Orlando, Jan. 19-21, 2007. Leonard B. Saltz, MD, gastrointestinal oncology service, Memorial Sloan-Kettering Cancer Center, New York City. Neal J. Meropol, MD, director, Gastrointestinal Cancer Program, Fox Chase Cancer Center, Philadelphia.