It's a new way to predict the course of the disease and in the process know which patients require aggressive treatment for long-term survival. It could also revolutionize treatment of all cancers.
In a study published in the May 10 issue of The Lancet, a group of Duke University scientists, working with researchers from the Koo Foundation Sun Yat-Sen Cancer Center in Taipei, China, offer the strongest evidence yet the system works, showing a 90 percent accuracy rate.
"Our model is the clearest example to date of a step toward personalized medicine," study author Dr. Erich Huang says in a statement issued by Duke.
Genetic profiling is a way of analyzing a breast cancer patient's basic cell information to develop "genetic signatures" that can ultimately be used to define risk levels of disease. In this study, the Duke team used a new type of gene-chip technology to closely examine the genetic comings and goings of cells in the tumors of breast cancer patients.
Then, applying a sophisticated method of statistical analysis, the researchers were able to generate a DNA "genetic signature" for each patient. Using that information they could predict -- with 90 percent accuracy -- the aggressive status of a breast cancer tumor, and whether a cancer was likely to recur.
Currently, removing and testing the lymph nodes -- cells that surround the breast -- is the only method available to assess a woman's long-term cancer profile and her current treatment needs. The condition of the lymph nodes are believed to be critical in determining long-term survival rates, since cancers that spread to these cells are thought to be more aggressive.
However, experts say it's not uncommon to find women with few or no cancerous lymph nodes whose disease recurs in just a few years, or those with extremely aggressive lymph node profiles who are effectively cured in just one course of treatment.
The genetic profiling system, the researchers say, will give a far more accurate prognosis and help doctors know from the start which women are likely to benefit from treatments such as chemotherapy and radiation, and which women can safely skip these regimens without compromising their future health.
For Dr. Harry Ostrer, director of the Human Genetics Program at New York University Medical Center, the new study validates earlier findings with yet more evidence that genetic profiling has a strong role in the future of cancer treatment.
"This study was well-executed and it definitely represents the direction in which we are going -- genetic profiling is something with a foreseeable clinical future," Ostrer says.
Because clinical trials are already under way utilizing various methods of gene profiling, Ostrer predicts that within five years or less the system will become part of every cancer patient's diagnostic regimen.
"It's very close to clinical application, and I think it will play a major role in determining the course of an individual's choice of cancer treatments, not only in respect to breast cancer, but all cancers," says Ostrer.
The new study involved 89 breast cancer patients, each of whom underwent tumor removal and subsequent biopsies of the lymph nodes. Simultaneously, they had genetic profiling.
The scientists then compared their genetic findings -- and predictions -- with the actual medical records that documented, in detail, the course of each woman's disease and all post surgical follow-up diagnosis and care.
The final result: The predictions made by the genetic profiling at the time of surgery were 90 percent accurate in determining the course of each woman's disease. This included predicting recurrences that, in many instances, did not develop until years after initial treatment.
Although previous research has been conducted on genetic profiling -- with similar results -- the Duke study was unique in that it utilized large collections of gene patterns to determine findings, something the researchers believe leads to a higher level of accuracy.
Still, the Duke researchers say they won't be satisfied until accuracy is closer to 100 percent, something they hope to accomplish in the near future as their methods of analysis are refined.
If genetic profiling does become widely available as a test, experts estimate that, at least initially, the cost will run about $2,000 per patient. That cost will likely be stacked up against the cost of routine chemotherapy and radiation, which genetic profiling may help many cancer patients avoid.