Redefining cancer could reduce unnecessary treatment

(CBS News) On Monday, a panel of excerpts advising the National Cancer Institute proposed changing the definition of cancer and eliminating the classification entirely for certain illnesses. The proposed changes, published in the Journal of the American Medical Association, could dramatically affect cancer detection and treatment

Tuesday, Dr. Davis Agus, a leading cancer specialist and the head of the University of Southern California's Westside Cancer Center, said slow-growing cancers must be redefined in order to reduce potentially damaging overtreatment.

There has been a "dramatic increase in certain kinds of cancer like thyroid cancer [and] melanoma," Dr. Agus said on "CBS This Morning," "Almost a 200 percent increase over the last 35 years."

The increase is due in part with new technology that is "allowing us diagnose many more cancers," he explained. "The problem is many of these cancers are not ever going to cause a problem."

"It's like if you told a firefighter, 'Go put out every fire, they'd be blowing water on tiki torches and candles when they don't need to. It's the same thing [with cancer]. Many of these cancers are so slow-growing, we need to redefine them."

The risk of aggressive treatment of slow-growing cancers include unecessarily undergoing "radical therapy" including surgery and radiation, treatments that could cause "lots of side effects when it's not needed," according to Agus.

"Lots of cancers ... we don't need to treat," he said, citing certain types of thyroid and breast cancers among them, "The key is to treat the cancers we need to treat, so we need a new definition."

Agus advises doctors to educate their patients about the range of treatment options available, so that patients fully understand potential side effects and ramifications and can weigh them against the risks of living with a slow-growing cancer.

"There rarely is one right decision. There's the right decision for the patient," he explained.