Fighting cancer: Newer drugs offering patients hope

Chemotherapy advances targeting specific cells with fewer side effects

April 23, 2009|By Deborah L. Shelton, Tribune reporter

When Glen Farkas learned he had late-stage colorectal cancer in 2003, his chance of surviving five years was almost nil.

Trying to beat the odds, he chose to undergo radiation, surgery and painful five-hour-long infusions of a cocktail of chemotherapy drugs. The treatments held the cancer at bay for about a year, but the cancer returned with a vengeance, invading his liver, bone and lungs.

The second time around, a drug called Avastin was added to his chemotherapy regimen. Not widely available in 2003, Avastin required only 10 minutes to transfuse, was painless and didn't cause side effects, Farkas said. As an added plus, he got his chemo in pill form, instead of intravenously.

The Los Angeles ophthalmologist has been cancer-free since December 2006. "In my opinion, [the addition of Avastin] turned my case around and saved my life," Farkas said.

Today's anti-cancer drugs are a far cry from medicine's first chemotherapy -- a form of mustard gas -- developed at the University of Chicago and two other universities and approved 60 years ago last month by the U.S. Food and Drug Administration.

Thanks in part to advances in genetic science, chemo is becoming more effective and far less grueling, and is transforming treatment for many cancer patients. The array of cancer-fighting medications is growing, and they are aided by new drugs that help treat nausea, minimize pain and boost levels of white cells to fight infection.

More than half of all people diagnosed with cancer are prescribed chemotherapy, a general term for drugs used to stop cancer cells from growing. Its advantage over surgery and radiation is that drugs can wage war on cancer cells wherever they are in the body.

Older chemotherapy drugs caused many difficult side effects because they couldn't distinguish between healthy and cancerous cells and attacked other fast-growing cells in the body, including hair and blood cells. The newer drugs are tailored to specific types of cancer and target particular types of cancer cells.

"These drugs are certainly less toxic and more effective than they used to be, in some cases, dramatically more effective," said Dr. Thomas J. Smith, professor of medicine and palliative care at Virginia Commonwealth University Massey Cancer Center. "A handful of cancers are controllable now that weren't controllable 5 or 10 years ago."

The drug added to Farkas' regimen, Avastin, is an example of this relatively new type of "targeted" cancer therapy. It includes monoclonal antibodies, laboratory-produced molecules that are engineered to attach to specific defects in cancer cells. The antibody makes the cancer cell more visible to the immune system, blocks chemicals that signal the cell to grow, delivers radiation to cancer cells and allows anti-cancer drugs to penetrate into the cells.

Avastin is also an anti-angiogenesis drug, meaning it interferes with the vessels delivering blood to cancer cells. Without a plentiful blood supply, tumors can't grow.

Despite the advances, chemotherapy is still far from perfect, and the risk of debilitating side effects remains. Some people tolerate the drugs better than others, and some cancers respond better than others.

Suzanne Lindley, who lives in Texas, has experienced a range of side effects from chemo, from rashes to loss of feeling in her extremities.

"I think there's still a big communication gap between patients and physicians about how those side effects affect the person," said Lindley, diagnosed with advanced colon cancer that has since spread. "It's one thing to see the side effects on paper. We have to live with them. It's a matter of quality of life."

As the field advances and cancer treatment becomes more complex, experts say doctors and patients will have to communicate better about the best course of action. That's especially true for patients whose conditions are terminal and who do not want medical intervention that might do more harm than good to their quality of life.

Physicians are coming around to the idea that chemo should not be the default position, Smith said.

"It's very hard to sit across from someone and tell them that medical science does not have a way to make them live longer," Smith said. "It's a lot easier to just give another round of chemotherapy. But that has to change -- and it is."

Increasingly, however, genetic tests are making it possible to tailor care so patients with treatable cancer receive drugs that are most likely to help them while avoiding the side effects of drugs that won't.

"It used to be, we gave everybody the same dose of chemotherapy and watched what happened and then made adjustments as necessary," said Dr. Richard Schilsky, a U. of C. Medical Center oncologist who is president of the American Society of Clinical Oncology.