Blood Test Holds Promise To Monitor Breast Cancer

A new blood test holds promise to aid in the treatment of advanced breast cancer, researchers report in the New England Journal of Medicine.

This new research gives hope to many observing national Breast Cancer Awareness Month in October.

The test, which looks for malignant cells in the blood, gives a quick read on how well women are responding to treatment for metastatic breast cancer, in which the malignancy has spread to other parts of the body.

"When a woman starts one of several treatments, all of which are designed to shrink the tumor and make people feel better, this test can tell in a few weeks whether the therapy will benefit her," says Dr. Daniel F. Hayes, a study author. "If not, she should be taking a different therapy."

Use of the test is in the earliest stages, says Dr. Hayes, clinical director of the breast oncology program at the University of Michigan Comprehensive Cancer Center.

Test Could Aid Therapy Choices

The study was conducted at 20 centers and focused on whether test results could tell how well a therapy was working.

A total of 177 women were tested, with the cutoff line for the test set at five cancer cells per 7.5 milliliters of blood. The average survival time for women whose readings were higher than that level was 8.2 months, compared to more than 18 months for those with lower blood levels of cancer cells.

But showing that a treatment is not helping a woman is just a first step, Dr. Hayes notes. "We still don't know whether, if a woman has these tumor cells, a switch to another therapy will help her," he says.

Breast cancer can be treated either with therapy aimed at reducing production of estrogen, a hormone that accelerates the growth of cancer cells, or chemotherapy, with drugs that kill cancer cells.

In this clinical trial, the blood test was more accurate in predicting response to hormonal therapy than chemotherapy, Dr. Hayes says.

But it does appear better than existing methods of evaluating the effectiveness of treatment, he says.

The most basic method is to monitor the woman's condition carefully, Dr. Hayes comments, with that evaluation occurring over a period of months.

The new test gives information in four or five weeks, he says.

There are older blood tests that look for cancer-related proteins, but their results are too uncertain to be widely used, says study co-researcher Dr. G. Thomas Budd, director of the medical oncology breast cancer program at the Cleveland Clinic.

"I believe that this method is more robust and gives more useful information," Dr. Budd says.

Goal Is to Support Survival and Quality of Life

A starting application of the test would be to "identify women who do not benefit from a treatment, so we can spare them the side effects," he says. "Then we would try to prove that changing the treatment improves survival or betters the quality of life."

Trials to determine whether a change of treatment based on the test will improve survival are in the planning stage, Dr. Budd says.

The test is done by a specialized machine recently approved by the US Food and Drug Administration, Dr. Hayes says.

The device is just becoming available at major cancer clinics, but a long-range hope is that results can be obtained by mailing blood samples to testing centers, he notes.

The test is currently intended for just 10 percent to 20 percent of breast cancer patients whose disease has spread, Dr. Budd says, but it might someday be useful for monitoring women who have been treated successfully for breast cancer.

"We could perform a test periodically to determine whether the cancer has recurred," Dr. Budd explains.

Always consult your physician for more information.

Online Resources

American Cancer Society

American Society for Clinical Oncology

Centers for Disease Control and Prevention (CDC)

National Cancer Institute

National Institutes of Health (NIH)

National Women's Health Information Center

Susan G. Komen Breast Cancer Foundation

October 2004

Blood Test Holds Promise To Monitor Breast Cancer

Test Could Help Aid Therapy Choices

Other Resources:

St. John's Mercy Cancer Services

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Mammography Linked To Better Survival Rates

Women whose breast cancer is detected by a mammogram have a better prognosis than women whose cancer is detected through other means, according to a report in the Journal of the American Medical Association.

October is national Breast Cancer Awareness Month.

The Finnish researchers report that those improved chances of survival lasted for up to 10 years after diagnosis, and the difference persisted even after compensating for such factors as age of the patient, grade of the cancer, and whether lymph nodes were involved.

The study, which looked at 2,842 Finnish women who had been diagnosed with breast cancer in 1991 or 1992, compared the survival outcomes of those who had had their tumors detected with mammography and those who had not.

The participants were followed for an average of nine-and-one-half years. Various features of the tumors were also compared.

Those women whose tumors were detected by means other than mammography had almost double (90 percent) the risk for cancer recurrence outside the breast.

Women whose tumors measured 11 millimeters to 30 millimeters in diameter and were detected by mammography had similar survival rates as women who had much smaller tumors (10 millimeters or smaller) that were detected without mammography screening.

The study results can be partially explained by a number of factors, including the size of the tumor, the hormone receptor status, and less likelihood of spread to the lymph nodes, the researchers say.

But the use of mammography appeared to play a role in the findings independent of these traditional risk factors for cancer.

Although mammograms are becoming more common and they are picking up smaller tumors, physicians traditionally have not considered the method of cancer detection important when choosing treatments or assessing risk of recurrence.

Most treatment decisions are based on whether the cancer has spread to the lymph nodes, the size of the tumor, the estrogen and/or progesterone receptor status, and the age of the woman at the time of diagnosis.

It is unlikely, however, that the study results will lead to mammography becoming another tool to help tailor therapy for women, some experts say.

"I wouldn't base my decision about whether to give chemo or not based on these results," said Dr. Ruth M. O'Regan, author of an accompanying editorial in the journal.

"If they confirmed this in another trial, then I definitely would take it seriously," adds Dr. O'Regan, director of translational breast cancer research at the Winship Cancer Institute at Emory University.

"It's very interesting data," Dr. O'Regan comments. "They did a very careful job of counting in all the prognostic factors that we usually take into account like tumor size and lymph nodes, and they still found that those who were screened did better.

"The interesting thing would be to look at the molecular level to see if there is some reason," Dr. O'Regan notes.

Another point to emphasize, says Dr. Julia Smith, an oncologist at New York University Cancer Institute, is that mammograms are picking up smaller tumors in older women. "That's not new but it reiterates an important point," she says.

Always consult your physician for more information.