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New Treatments Take a Finer Aim at Cancer Cells

Posted on: Friday, 6 April 2007, 06:00 CDT

ST. LOUIS _ Cancer survivors know the aftermath of chemotherapy: The cancer may be gone, but not the side effects of the drugs.

Chemotherapy, the use of chemicals to fight cancer, often is feared as much as the disease. In fact, the treatment can be so harsh that some people have had to accept disabilities as a trade-off for survival.

Sarah Smallen, 24, has survived 11 years without a recurrence since suffering leukemia as a 12-year-old. Her experience with cancer led her to become an oncology nurse. She still has a numbness in her arms and trouble walking from time to time. Surgery eased the pain in her jaw.

But she's alive.

Then there's Amanda Carter, diagnosed in 1999 at age 19 with Hodgkin's lymphoma. Since chemotherapy, her fingers still get numb in cooler temperatures, and she lives with blurry vision and forgetfulness.

Her cancer appears to be gone, although she undergoes yearly tests to make sure.

Doctors see the day when they can reduce these accounts to mere history lessons.

New drugs and substances, as well as an intensified team approach to fighting cancer, have produced what they call "targeted therapy."

Targeted therapy's aim is to customize treatment for each individual with better drugs and a team approach rather than the one-size-fits-all process used for decades.

The targeted therapy movement is led by a new family of chemotherapy drugs, says Dr. Mark Clanton, chief medical officer for the High Plains Division of the American Cancer Society.

The drugs attack the things that make cancer unique. The new drugs have fewer side effects because they go after only the cancer, Clanton says.

It works this way:

A cancer cell is a normal cell that has mutated into a monster. Among the different varieties of cancers are varieties within the varieties.

The only things they have in common are that they divide rapidly, live longer and take up more room than normal cells.

The old-style chemotherapy drugs attack not just cancer cells but also normal cells that divide rapidly: hair follicles, white blood cells, bone marrow, the lining in parts of the digestive tract and others. So people who endure chemotherapy often suffer from the temporary effects of hair loss and nausea.

Other effects can be long-lasting: immune system deficiencies or anemia caused by damage to the bone marrow. In fact, chemotherapy can lead to the need for future bone marrow transplants.

Permanent injuries can include nerve and brain damage, especially among children. Some cancer patients have contracted a condition called "chemo-brain," in which they lose some alertness after the therapy. The nerve conditions can last a lifetime.

And then individuals can have problems unique to them, doctors say.

But that's the trade-off of using chemotherapy, says Dr. Bethany Sleckman, director of oncology research at St. John's Mercy Medical Center in St. Louis. Patients are alive, but there can be lasting damage.

That's why doctors and cancer patients welcome a new, selective therapy, Clanton says. New therapies hunt down the parts of the cancer cell that make it cancer. No other cells in the body have those parts.

This became possible shortly after scientists mapped the human genetic system (genome), which gave researchers templates to find mutations in cancer cells.

With that new information in hand, they've taken the next step: finding drugs that attack unique cancer parts while ignoring innocent cells. The upside is that the side effects of the new drugs are nowhere near so devastating as the side effects of the old drugs, says Dr. Timothy Eberlein, director of the Siteman Cancer Center.

"We're finding more targeted (therapies) less toxic," Eberlein says. "And many of these more targeted therapies are more effective."

The downside of specific therapies is that drugs must be developed for every variety and subvariety of cancer.

For example, a popular targeted breast cancer drug is so specific it attacks only 10 percent of breast cancers _ unlike the old drugs that attacked everything.

Numerous drugs are in clinical trials, says Sleckman.

Currently, targeted therapies exist to fight types of colorectal cancer, lung cancer, breast cancer, kidney cancer and others.

One targeted drug fights the deadly condition myelogenous leukemia and "leads to long-term remissions, and perhaps cure, in about 90 percent of patients with a disease that previously required a bone marrow transplant for cure," she says.

"Our ultimate goal is to have targeted treatments available for all cancers, and we are getting closer to that ideal each year," Sleckman says.

Meanwhile, targeted drug therapies for many other types of cancer are in clinical trials. Eberlein says that in the next 10 years, expect more targeted therapy to use genetic information to help fight cancer.

The ultimate goal is to produce a system in which a person with cancer can get a diagnosis and treatment unique to the person, he says.

The new therapies will change the face of cancer therapy, Clanton says.

For example, a targeted drug may stop the cancer but not kill it.

"The new targeted drugs allow people to convert what used to be lethal cancers into chronically maintained cancers that people won't necessarily die from," he says.

That means taking a pill or pills every day to keep the cancer in check with or without radiation or surgery.

It also means that the earlier cancer is detected, the better.

So prevention and screening become a major part of the battlefront, Eberlein says. "If you have a community of smokers, it's a lot cheaper to start a program to stop smoking."

That also means more screening and monitoring.

Most important, Clanton says, the new approach means people must take more control of their health even when deciding therapy.

The ability to aim a drug at a particular cancer opens the door to more collaboration between doctors and patients, Clanton says. In the past, the physicians treating a cancer patient _ the oncologist, the surgeon and the radiation oncologist, for example _ often didn't talk to one another or even know one another.

With specific therapies, those folks will have to work together to decide on what to do for each patient, Clanton says.

"The challenge to the health-care system is, how do we organize ourselves into comprehensive and coherent groups in order to treat that patient?" Clanton says. "Today, you have to go to a group of physicians who have to talk to each other, share information. That's difficult to do."

Although cancer centers have made the process routine, he says, about 70 percent of cancer patients don't go to cancer centers.

The communication and the new therapies offer cancer patients many more choices, Clanton says, choices that fit the values of an individual.

A person facing cancer may select quality of life, mobility and alertness over longevity that would require surgery and long recuperation, Clanton says. Or someone may ask to be kept alive no matter what it takes.

"It used to be that the doctor would say, `Here's what's going to happen,'" Clanton says. "That's no longer the case."

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QUESTIONS TO ASK YOUR DOCTOR OR NURSE

The American Cancer Society lists these suggested questions for cancer patients:

-- What is the goal of chemotherapy for my cancer?

-- What are the chances that the chemotherapy will work?

-- Who will be involved in the treatment?

-- After chemotherapy, will I be cured, in remission, relieved of my symptoms?

-- Are there other ways to achieve the same goals? Is chemotherapy my only option?

-- How will I know if the chemotherapy is working?

--What if it doesn't work?

-- What are the potential risks and side effects of the chemotherapy I will be taking? How do side effects of this chemotherapy compare with side effects of other treatments?

-- How will I receive chemotherapy, how often and for how long?

-- Where will I be given the drugs?

-- Are there ways to help me prepare for treatment and decrease the chance of side effects?

-- Will my diet be restricted in any way? My activities? My work? Exercise? Sexual activities?

-- Will I be treated with surgery, radiation or both? If so, when and why? What are the expected results of each type of treatment?

-- Who will be involved in the therapies?

-- If chemotherapy is to follow surgery or radiation, will it destroy any remaining cancer cells? Could chemotherapy be used alone?

-- Are there any clinical trials I could take part in?

-- How much will chemotherapy cost? Will it be covered by my insurance or health plan? If the insurance company requests a second opinion, or if I would like one, whom do you suggest I see?

Source: St. Louis Post-Dispatch

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