New Drug-Delivery Systems
Nanotechnology is a term you’ll hear more of when it comes to breast (or any) cancer research. Basically, nanotech involves devices 80-100,000 times smaller than the width of a human hair. Since cancer happens at the cellular level, these tiny technologies have the potential to prevent, detect and treat cancer in ways never before imagined.
Earlier this year, one nanotech drug, Abraxane by American BioScience, was approved for advanced breast cancer. The active ingredient is Paclitaxel, also found in the chemo drug Taxol, but Abraxane’s tiny particles ferry the therapy right to the tumor, so patients don’t need extra drugs or ingredients to dampen down side effects.
Nanotechnology can also make drugs more effective. Initial studies have found that Abraxane may allow patients to safely receive 50 percent more active ingredient per dose than the traditional delivery method, shrinking tumors faster and to a greater degree. The verdict is still out on whether this will affect survival rates, but models developed by Larry Norton and his colleagues at Sloan-Kettering already support the idea that "dose-dense" treatment—delivering the most doses possible in the shortest period of time—is the most effective way to stop cancer. This treatment is based on the notion that tumors grow and die according to predictable patterns. The trick is frequency; giving a small dose more often means more medicine can be administered over the same time period with less toxicity, so the drug knocks out as much cancer as possible without taking as great a toll on the patient. "Now that we know certain patterns of growth are important, finding the molecules responsible for them may lead us to the cure," says Norton.
Better, Earlier, Detection
Nanotechnology may also be used to detect cancer at earlier stages. Launched into the breast or elsewhere, such particles will act as tiny probes, taken into cancer cells too small to be detected by conventional methods. These anocrystals may be used to bind to cancer or normal cells, making them more visible with MRI or other types of scans.
It’s not nearly as futuristic as it sounds. In March, the FDA moved a step closer to approving a nanoparticle known as Combidex, developed by Advanced Magnetics, Inc., which, when used with an MRI, will help distinguish normal from cancerous cells. Right now, the only way for doctors to find out if cancer has spread is to remove or biopsy one or several lymph nodes. The nanoparticles have the potential to detect cancers accurately without the removal of even a single lymph node. Soon, nanoscale devices may allow doctors to multitask, both detecting cancer at its earliest stages and simultaneously delivering anticancer agents.
Other new detection methods identify the growth of new blood vessels that could signal the emergence of cancer. Clinical trials have begun on ComfortScan, a new device from DOBI Medical International that detects increased blood-vessel creation. The ten-minute scan won’t be dramatically different from a mammogram
Another tool, iFind, may revolutionize breast self exams. The handheld device responds to the higher level of hemoglobin found in cancer tissues, which require more blood and oxygen than surrounding tissues. In a small study, the device was96 percent reliable in detecting cancer. Although larger trials are needed, developers say the device, expected to cost less than a few hundred dollars, could be available in as few as two years. It won’t replace mammograms, but it will give women a useful tool for monitoring their breasts between screenings.
New Tools to Prevent Cancer
Drugs are also being studied for their prevention potential. Aromatase inhibitors, such as AstraZeneca’s Arimidex, Novartis’ Femara and Pfizer’s Aromasin, dramatically reduce recurrence in women with early stage disease; now investigators hope to design studies to determine if the drugs can just as dramatically cut the rate of occurrence in women at high risk for the disease.