TUESDAY, Dec. 6 (HealthDay News) -- New research points to two gene-based methods of predicting if and when women with certain breast cancers will experience a tumor recurrence.

The studies, involving two common forms of breast cancer, are slated to be presented Wednesday at the 2011 San Antonio Breast Cancer Symposium.

The research also revealed that genetic data gleaned from tumors might help doctors tailor treatments to individual patients, sparing low-risk women from exposure to unnecessary radiation, for example.

In one study, researchers from the Eastern Cooperative Oncology Group, North Central Cancer Treatment Group and Genomic Health found that a multi-gene test can predict the risk for recurrence among women who have been diagnosed with ductal carcinoma in situ, or DCIS (a type of early cancerous growth limited to the breast duct).

In conducting the study, researchers analyzed genetic information from the tumors of 327 women diagnosed with DCIS, to calculate their risk for recurrence. By differentiating between low-risk and more aggressive forms of the disease, the "DCIS Score" predicts the likelihood of local recurrence and might help doctors determine if patients should be treated with surgery or a combination of surgery and radiation.

"The DCIS Score will help physicians understand the underlying biology of DCIS for an individual patient and accurately gauge the risk for that person," Dr. Lawrence Solin, chair of the department of radiation oncology at Einstein Medical Center in Philadelphia, explained in a news release. "As a result, the patient and physician can decide on the appropriate course of treatment based on a more complete understanding of the risk involved."

Cancer experts were cautiously optimistic about the results.

"Ductal carcinoma in situ represents the earliest stage of breast cancer -- cancer cells that have not yet broken through the basement membrane of the breast duct," explained Dr. Kerin Adelson, a medical oncologist specializing in breast cancer at Mount Sinai Medical Center in New York City. "In standard practice women who undergo lumpectomy for DCIS are treated with radiation to prevent local recurrence in the breast," she added.

However, "it has long been clear that some women are at higher risk for local recurrence than others," Adelson said. The new data "show that molecular profiling can be used to predict which cases of DCIS are at high risk for local recurrence and which are not. This may spare women with lower risk DCIS the need for breast radiation."

Another expert called the results "exciting," but had some reservations. "Although the authors state that this can be used to help eliminate radiation in some women, we may not yet be at that stage," said Dr. Stephanie Bernik, chief of surgical oncology at Lenox Hill Hospital in New York City. "The rate of recurrence was still 12 percent in the low-risk group and many clinicians and patients may not feel this is acceptable," she said.

Still, "even if we have not eliminated the need for radiation, the findings in this study are extremely significant because we will have more information to offer patients about their specific kind of DCIS," Bernik reasoned. "The findings also open the door to additional studies that will eventually allow us to avoid overtreatment and undertreatment of DCIS."

In the second study, researchers from Georgetown Lombardi Comprehensive Cancer Center and the University of Edinburgh zeroed in on molecular differences in tumors that can be used to predict whether or not women with hormone receptor-positive invasive breast cancer will experience recurrence of the disease and when. Hormone receptor-positive tumors are influenced by estrogen.

The researchers noted their findings could help explain why some women experience recurrence of this type of breast cancer up to 10 years or more following their original diagnosis.

"We confirmed what many have already suspected," said Dr. Minetta Liu, associate professor of medicine and oncology and director of translational breast cancer research at Georgetown Lombardi Comprehensive Cancer Center, in a news release. "There are biological drivers that define -- at the time of tumor development -- whether or not breast cancer will recur early, late or not at all. Now we need to validate these findings and take our knowledge to the next step."

In the study, researchers identified gene expression patterns among tumor samples that were strongly linked to the development of metastatic disease later in life.

"There are clear biological differences within the supposedly unified group of hormone receptor (HR)-positive breast cancers, and these differences distinguish subtypes relative to the time at which they recur," said Liu. "Understanding what drives these distinctions will allow us to tailor treatment and improve patient outcomes."

Bernik and Adelson agree that these types of tests may be the wave of the future.

"We have long known that tumors do not always behave as we would predict," Bernik noted. "At times tumors with aggressive features are completely eradicated, and at other times tumors that are thought to be less ominous are found to cause metastatic disease years later. When we look cancers from a molecular level, we are looking at the mechanics of what makes a cell function and grow. This is ultimately the way we can figure out how to turn off the machine that drives the cell to divide, grow and spread," she said.

Adelson concurred, saying that tests like those outlined by the Georgetown team "may help personalize cancer treatment to an individual patient's risk."

Experts caution that information presented at medical meetings should be considered preliminary until published in a peer-reviewed journal.

More information

The U.S. National Cancer Institute provides more information on how to assess breast cancer risk.