Cancer: the Good, the Bad, and the Ugly
We've made great progress since President Nixon declared war on cancer 30 years ago, but can the war be won?
The Katie Couric Curve continued...
"We are picking up earlier cancers and that's making a difference, and part of the difference is also very good chemotherapy for colon cancer," he says. For example, it used to be that if colon cancer had spread to the liver, "survival was nine to 11 months, but now we can resect the liver and chemotherapy kills the microscopic disease, so we seeing survival in the range of 50%," he tells WebMD.
Overall, "advances in cancer have been in treating the microscopic disease," he says. "Chemotherapy for breast cancer and colon cancer has significantly improved because we can kill the small disease that is not visible and regrows either in the vicinity of the cancer or spreads throughout the body." Chemotherapy can knock out errant cancer cells along with the main tumor.
The rates of colorectal cancer have dropped between 1998 and 2001 in both men and women. Prostate and female breast cancer rates have continued to increase, although at a slower rate than in the past. However, the increase may be due to increased detection because of higher rates of screening using prostate specific antigen test for prostate cancer and breast X-ray or mammography for breast cancer.
New Warriors Join Battle
New "smart" drugs are also promising weapons in this war. "This year, there has been enormous progress in the angiogenesis inhibitors, and it is the first year that there has been a significant increase in survival of the three top cancers - colon, breast, and lung -- due to antiangiogenic therapies being introduced," Folkman tells WebMD. Antiangiogenic drugs, also called angiogenesis inhibitors, starve tumors to death by cutting off their blood supply.
For example, Avastin targets a protein called vascular endothelial growth factor (VEGF), which plays a role in making new blood vessels for tumors (a process called angiogenesis). This drug was approved in the U.S. for colon cancer in February 2004, and by January 2005 it had been approved in 27 other countries, he says.
Other antiangiogensis drugs being used include thalidomide and Tarceva. Tarceva blocks tumor cell growth by targeting a protein called HER1/EGFR that is important for cell growth in advanced nonsmall cell lung cancer. Tarceva "blocks three angiogenic proteins and really is an angiogenic inhibitor," Folkman says. Thalidomide became notorious in the 1960s when it was prescribed to pregnant women to ease morning sickness, but was found to cause severe birth defects by limiting the blood flow to developing limbs. As a result, many children were born limbless or with severely shortened limbs. Now scientists are capitalizing on these same blood-limiting properties to help block the blood supply to tumors.