Using microwaves to shrink tumours

The shrinkage, using technology developed for a missile defence system, helps eliminate stray cancer cells and minimises damage to the breast during lumpectomy


Lumpectomy to remove small breast tumors is an important option for women, allowing many to survive cancer and keep their breasts. But one drawback to lumpectomy – of which many women are unaware – is that one-fourth to one-half of patients have to return for a second surgery to remove more tissue.

Researchers say they are fast developing tools that could dramatically reduce the need for a second surgery, called "re-excision".

Moreover, their work could lead to new treatments for even larger tumours, which often require mastectomies.

Using microwave technology developed for a space-based missile defence system, doctors at the Research and Education Institute at Harbor-UCLA Medical Center are shrinking tumours before surgery. Such shrinkage helps eliminate stray cancer cells and minimises damage to the breast during lumpectomy.

"We're trying to kill the cancer cells with a less invasive technique," says Dr. Hernan Vargas, director of the Breast Clinic at Harbor-UCLA Medical Center. "The ideal treatment for cancer is to kill the bad cells without damaging the normal cells."

In lumpectomy, doctors make a small opening in the breast and remove the tumor along with a 1- to 2-centimetre margin of healthy tissue. That healthy tissue is later examined under a microscope for evidence of cancer. If cancer cells are present, more tissue is removed.

"The question for the surgeon is how much tissue to take out," Vargas says. "You want to leave enough so the woman has a breast with a normal shape and look. But we don't want the cancer to come back."

Even when the margins are "clean", breast cancer recurs in some women, he says.

The technique Vargas and others are testing, called Adaptive Phased Array microwave technology, could dramatically reduce re-excision rates and lessen the chances of cancer recurrence. It works by targeting breast tissue with high water content (the cancer cells) while sparing tissue with low-water content (healthy cells).

The treatment, which is performed a few weeks before the lumpectomy, is fairly quick and low-risk.

A small needle with a thermometer is inserted through the skin into the tumour. More thermometers are placed on the surface of the breast.

A cooling system protects the skin while the microwave device heats the tumour. The procedure takes about 20 minutes and requires local anesthesia.

In a recent study, no cancer cells were found outside the lump in 24 of 25 women. The therapy also shrank the tumours in many women, Vargas says.

In 80 per cent of the cases, tumor cells were damaged by the therapy, and some patients who had higher doses of microwave therapy had much of the cancer destroyed before surgery. Two patients suffered mild burns.

Researchers at Harbor-UCLA and several other sites are conducting a similar study of 500 patients. A separate study of several hundred women with more advanced breast cancers, which typically require mastectomy, also is under way. They will undergo chemotherapy and microwave therapy before surgery to see if tumours can be shrunk enough to permit lumpectomy instead of mastectomy. Both trials are being conducted by Celsion Corp. of Columbia, Maryland, USA, which makes the device.

The long-term goal of the research, says Vargas, is to destroy tumours before surgery.

Scientists also are testing radio frequency waves and cryotherapy to shrink tumours and are combining these heating and freezing therapies with chemotherapy and new cancer drugs.

"We see these minimally invasive treatments as part of the evolution of treating breast cancer," he says. "The goal for the future is that we'll be able to treat cancer without surgery at all."


Two drugs to aid colorectal cancer patients

By Justin Gillis
Doctors recently reported that a new drug designed to block the growth of blood vessels in tumours improved the survival of patients with advanced colorectal cancer by 50 per cent, a finding that could rapidly change the way the second-leading cause of cancer deaths in the United States is treated.

Another study, unveiled at the same cancer meeting in Chicago as the first, revealed that Erbitux, the much-maligned cancer drug at the centre of a swirl of insider stock-trading investigations involving Martha Stewart and others, offered notable benefits for some colorectal patients in whom other treatments had failed. The drug also benefited lung cancer patients in preliminary research. It now appears likely to win eventual approval from the Food and Drug Administration.

Doctors said the findings herald the dawn of an era when cancer treatments designed on the basis of detailed genetic knowledge will begin to have a significant impact on the types of cancer that kill the most people – those of the lung, breast, colon, and prostate. Researchers have been working on these "targeted" therapies for two decades, but they have just reached the point where they have overcome initial problems, mounted large-scale tests and begun to obtain convincing evidence that the drugs work.


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