Why Cancer Screenings May Soon Be as Easy as Taking a Pregnancy Test

For decades, scientists thought of cancer as simply a disease of good genes gone bad. Whether a person's DNA contained inherited mistakes or became damaged as cells went about their daily business, these glitches allowed cells to multiply unchecked. If they could find a way to stop the cells from reproducing, scientists assumed, they could cure the cancer. But today it's clear that the mechanisms behind the disease are far more complex. Oncology researchers have discovered that a tumor's growth is as much a product of its surrounding environment as it is of genetics. Research has also shown that even when two people have the same type of malignancy, the cellular changes that cause their tumors may be unique to each patient.

Although such findings suggest there may never be a universal cure for cancer, they have paved the way for more precise screening tests and more effective treatments. "We're on the brink of genuinely changing cancer treatment for the better," says Razelle Kurzrock, MD, head of the department of investigational cancer therapeutics at the University of Texas M.D. Anderson Cancer Center in Houston.

Already, targeted therapy—medications aimed at specific cells with certain mutations or other characteristics—is being used in some cancer treatment centers, and it will only become more common as the decade goes on. "In the past five years, we've realized that there's no 'one size fits all' when it comes to cancer," says Eric Winer, MD, director of breast oncology at the Dana-Farber Cancer Institute in Boston.

In fact, "we're heading to the day when cancer treatment will look a lot like modern infectious disease treatment," Kurzrock says. Not so long ago, nearly all patients with bacterial infections got penicillin. But just as doctors can now analyze a culture of your infection and match an antimicrobial drug to your particular germ, oncologists will one day be able to obtain your tumor's genetic fingerprint and devise a specialized drug regimen just for you.

The next step will be identifying more cancer triggers to target. The breast cancer drug Herceptin, FDA approved in 1998, was one of the first treatments developed to home in on a specific genetic flaw—in this case, a defect in the HER2 gene, which is responsible for about 20 to 30 percent of breast cancers. A decade of experience with Herceptin and similar drugs has demonstrated that treatment can be more effective and have fewer side effects when it hits a precise genetic mark—but we've also learned that most cancers are likely driven by more than one mechanism. Today researchers are working on drug cocktails that can hit several bull's-eyes at once. Early trials suggest some of these drug combinations are more effective at shrinking tumors and halting disease progression than existing medications.

In the next decade, the best treatment for some patients may be no treatment at all

Scientists have also discovered that, just as a seed needs soil and water to grow, a tumor needs surroundings that will nurture it and allow it to spread. "Uncontrolled cell growth is necessary for cancer to develop, but it's not sufficient to make it metastasize," says Donald Ingber, MD, PhD, director of Harvard University's Wyss Institute for Biologically Inspired Engineering. In the works are treatments designed to make the environment around a tumor less hospitable.

For example, a class of drugs called angiogenesis inhibitors (angiogenesis refers to the formation of new blood vessels) slowly starve tumors by preventing them from forming the blood vessels they need to grow. "Currently, these drugs are used to treat late-stage cancer," says William Li, MD, president and medical director of the Angiogenesis Foundation. "As we gain more knowledge about the biology that drives cancer to develop, we'll be able to pinpoint the exact stage of the disease when antiangiogenesis treatments can do the most good."

But tumors do more than grow new blood vessels—they sabotage the whole architecture of the tissue around them. The goal of many drugs in development is to alter the signals between cancer cells and their surroundings. Ingber, who helped develop some of the first angiogenesis drugs, is working to create a polymer gel that could be injected into a surgical site after a tumor is removed. The gel would repair damage in the surrounding tissue so that even if a few cancer cells remained, they couldn't take root.

In the next decade, the best treatment for some patients may be no treatment at all. Research has shown that many tumors are essentially harmless and will stagnate or regress on their own. The problem is, we can't tell the dangerous tumors from their less virulent counterparts, so nearly all cancer patients end up enduring the side effects of chemotherapy and radiation. As researchers begin to understand how cancer cells transform from benign to deadly, doctors may be able to test the genetic makeup of a tumor and determine when treatment is—and isn't—necessary.

The need for harsh treatments will also decline as doctors are better able to detect tumors when they are smaller and easier to stop. Today even the best means of early detection are prone to false positives, or they miss the cancer entirely. (Mammography, for example, reduces death rates from breast cancer by only 20 to 30 percent. That means if 30 out of 1,000 women would normally die of breast cancer, screening would save only six to nine of them.) But before this decade ends, we may see a diagnostic test for most types of cancer that's as cheap and easy as a pregnancy test, says Don Listwin, head of the Canary Foundation, a nonprofit research group in Palo Alto, California, dedicated to improving cancer detection.

For the past decade, Marsha A. Moses, PhD, and her colleagues at Harvard Medical School and Children's Hospital Boston have been developing a method of detecting, in urine, the proteins that are the calling cards for many types of cancer; these proteins show up long before a tumor grows large enough to appear on a scan. A prototype urine test is now in the final stages of testing. In the future, Moses says, "when you go for a checkup, your doctor could use a urine sample to check for some of these markers," in the same way a cholesterol check can now signal the possibility of heart disease.

Kurzrock became an oncologist in the early 1980s because she thought cancer treatment would be transformed in her lifetime. Now, for the first time, she feels as if she's on the verge of that long-awaited revolution. "It's hard to imagine not being scared of a cancer diagnosis," she says. "But I see it changing from the number one killer in the world to a disease that we know can be treated."

Male birth control? It could happen by 2020. Click here to read about 4 amazing new health breakthroughs