New Diagnostic Tools
In a standard mammogram, the breasts are X-rayed and tumours show up as white dots or masses on the film. Some women, however, particularly younger ones, have dense breasts with lots of fibrous and glandular tissue. This makes it difficult to spot tumours on traditional film. “Trying to find a tiny tumor is like trying to find a needle in a haystack,” says medical oncologist Ellen Warner at Sunnybrook Health Sciences Centre in Toronto.
For these women, digital mammography is a more effective diagnostic tool. The breasts are still X-rayed in the same way, but the image is captured on computer and radiologists can adjust the resolution, block out some background density and focus on suspicious areas for a clearer image.
Sunnybrook and some other Canadian hospitals are now using digital mammography. It’s great for communities that may not have a radiologist because a technician can do a mammogram at a local hospital and then send the images by email to another hospital, where a radiologist can read them.
MRI (magnetic resonance imaging) uses magnetic waves to create a three-dimensional image. “You’re actually taking [looking at] lthin slices of the breast. So it’s easier to find a small tumour inside the breast because you don’t have to look through the entire breast thickness,” Warner explains. A contrast agent is also injected intravenously, which lights up the tumours.
But MRI is very expensive and does sometimes produce false positive results. So it’s currently only used for women who have a strong family history of breast cancer, who have a genetic mutation or who’ve had radiation for Hodgkin’s disease.
New Treatment Options
About 20% of breast cancer cases are HER-2, an aggressive form of cancer. A drug called Herceptin has been the best treatment for women with HER-2 cancer. “Herceptin attacks the outside of the HER-2 protein,” says Dr. Edith Perez, hematologist, oncologist and researcher at the Mayo Clinic in Florida. But sometimes women have an intrinsic resistance to the drug or develop a resistance to it during treatment. Tykerb also targets the HER-2 protein but binds to the inside of it, Perez says. Additionally, Tykerb can be taken orally as a tablet, while Herceptin is given intravenously. And Tykerb does not raise your risk of heart damage to the extent Herceptin does.
Tykerb is now in phase III clinical trials in Canada and a marketing application has been submitted to Health Canada. In the US, the drug has been approved for women with advanced breast cancer and Perez is spearheading a worldwide study called ALTTO, which will evaluate Tykerb’s effectiveness in treating early-stage breast cancer.
Sutent, a breakthrough drug treatment in kidney cancer, is now being studied for breast cancer treatment. It targets vascular endothelial growth factor (VEGF) to inhibit the formation of blood vessels (which tumours need to grow) and other types of molecules that stimulate tumour growth, Warner explains. It’s also in clinical trials in Canada.