Using a DNA marker that can be obtained via a blood test, researchers in Canada were able accurately to predict which women were more likely to see a recurrence of their breast cancer years later. Although more studies are needed to confirm their findings, they suggest they could complement current prognosis approaches based on tumor assessment.
Sambasivarao Damaraju, a professor with the Faculty of Medicine and Dentistry at Canada’s University of Alberta, and colleagues, write about their findings in the 16 January issue of the open access online journal PLoS ONE.
Current Prognoses Methods Based on Tumor Assessment
Damaraju says in a statement that while some breast cancer patients receive an excellent prognosis, the cancer still comes back. And other patients remain cancer free, even though they receive a poor prognosis.
This is because, as he and his colleagues note in their study background, current breast cancer recurrence prognoses use tumor-based assessments, which they describe as “not optimal determinants” of the risk of breast cancer recurrence.
For their study, Damaraju and colleagues focused on good prognosis breast cancer: that which has a high success rate in terms of initial recovery and treatment. Around 70% of breast cancers fall into this category.
But, although initial treatment succeeds, there are still substantial deaths due to cancer spread in this group. Damaraju and colleagues suggest this is because so many receive a good prognosis.
DNA Marker Combined with Tumor-Based Markers Would Improve Accuracy of Diagnoses
Damaraju says the accuracy of tumor-based markers could be improved if combined with their DNA marker method, which can be assessed from a simple blood test.
Currently, treatment options are based on what doctors find about the tumor: such as the size, grade and what markers are present or not in the tissue.
But Damaraju says:
“If we can accurately predict which women are at high risk of breast cancer recurrence, it gives the physicians and oncologists treating those women time to design a more aggressive therapy in hopes of preventing the cancer from coming back.”
“Treatment strategies could be tailor made for these women based on their genetic make-up and how susceptible it makes them to breast cancer recurrence,” he adds.
Copy Number Aberrations
For their study, the researchers scanned the entire genomes of 369 women diagnosed with breast cancer.
Of these, 155 experienced a recurrence of their breast cancer, while 214 did not.
In scanning the genomes, the researchers looked for a type of marker called copy number aberration (CNA). This is where the DNA of the genome has an abnormal number of copies of one or more sections of DNA (either too many or too few).
CNAs are not unusual in the human genome, but they are more prevalent in cancer cells.
The researchers note that CNAs have not yet been evaluated as potential markers of breast cancer recurrence.
They found 7 CNAs that showed a statistically significant link to recurrence free survival.
They also found another three CNAs that showed a significant link to recurrence free survival when the types of breast cancer were restricted to luminal A, the most common form of breast cancer and the type that generally has a good prognosis.
They conclude that their findings are strong enough to justify further investigations on the use of DNA markers in formulating prognoses of breast cancer.
The team is continuing to work in this area, and wish to go ahead with a larger study to confirm their findings, which they hope to publish in about three years.
Damaraju says two years after that, he hopes to have a DNA predictor test in clinical trials before making it widely available for patients.
Trish Bronsch, CEO of the Prairies/NWT Region of the Canadian Breast Cancer Foundation, one of the two study funders, says they were very excited about funding the study, and describes its impact on personalized treatment for breast cancer patients as “substantial”:
“Knowing individual risks of breast cancer and recurrence provides doctors and oncologists with a better picture in which they can create a treatment plan to fit personal needs,” she adds.
The Alberta Cancer Foundation is the study’s other funding partner. Their CEO, Myka Osinchuk, says they are pleased to “see donor dollars having a direct impact on outcomes that are important to Albertans”, and excited to follow the team “to ensure those women successfully treated for breast cancer continue to live cancer-free lives”.
In June 2012, researchers from the The University of Texas reported how testing the blood of early stage breast cancer patients for circulating tumor cells (CTCs) may predict their chance for recurrence and survival.