What you must know about biopsies

When you really need one and how to get the clearest results

Published: July 13, 2015 06:00 AM

If you’re scheduled for a biopsy—which involves removing a small piece of tissue and examining it under a microscope—it often means that your doctor suspects you may have cancer. That can be scary enough. In addition, although millions of Americans undergo biopsies each year, experts often disagree on who needs one and what the results might mean.

For example, a March 2015 study found that pathologists reading the same breast cancer biopsies reached conclusions that differed from those of an expert panel’s almost 25 percent of the time. Those differences could lead to improper care: not receiving lifesaving therapy when you need it or undergoing aggressive treatment when simpler measures may be enough. Getting a biopsy when you don’t need one can also lead to problems. Those can include unnecessary anxiety and expense, as well as needless risk, because biopsies can cause bleeding, pain, and other complications.

Confusion can start before the biopsy, with the screening tests that often trigger biopsies. That’s because there’s widespread disagreement on who, for example, really needs a mammogram to check for breast cancer or the blood test that measures PSA, or prostate specific antigen, to look for prostate cancer. “One of the best ways to avoid unnecessary biopsies is to avoid unnecessary screening tests,” says Consumer Reports’ chief medical adviser, Marvin M. Lipman, M.D.

We’ve looked at four common cancers, and here we explain when screening and biopsies are warranted for each:

Breast cancer

As mammograms have become standard, so have breast biopsies. Almost 1.6 million U.S. women each year now get one. And almost 10 percent of women ages 40 to 59 who have a mammogram every year for a decade will be told at least once that they need a biopsy. Most come back showing no cancer. Still, a biopsy can trigger worry and follow-­up tests.

Who should be screened. Though many women get mammograms every year starting at age 40, research has not conclusively shown that doing so saves more lives than starting a little older and being screened less often. And earlier, more frequent screening increases the chance of biopsy. The U.S. Preventive Services Task Force, an independent group that develops recommendations for the government, says women ages 50 to 74 should have mammograms every two years. Other women should talk with their doctor to see whether the test makes sense for them.

When you need a biopsy. You usually need one if you or your doctor feels a breast lump or if a mammogram detects a mass or tiny specks of calcium arranged in a cluster or a line. Such calcifications can be an early sign of breast cancer.

When you can wait and see. If an abnormal image doesn’t provide definitive results, many radiologists reflexively recommend a biopsy, just to be safe. But in that situation, repeat imaging in a few months might be a good idea, says Clifford Hudis, M.D., chief of the breast medicine service at Memorial Sloan Kettering Cancer Center in New York City. The same may hold true even if a small lesion is found.

You should know. Biopsies may sometimes be unclear. In that case, a surgeon may need to remove a larger piece of tissue to examine.

Prostate cancer

About a million U.S. men per year get a prostate biopsy, most after having a PSA blood test, which measures a protein produced in large quantities by cancer cells. But the PSA can be unreliable. Factors such as riding a bicycle, benign enlargement of the gland, and infection can also raise PSA. What’s more, it is common for men to have a non-­life-­threatening form of prostate cancer. But the PSA test, and even the biopsy, can’t always distinguish between slow-growing and aggressive cancers.

Who should be screened. The benefits of routine screening are so uncertain that the task force recommends against routine PSA testing.

When you need a biopsy. You may need one if you have symptoms that could be prostate cancer, such as a frequent need to urinate and blood in urine or semen, or if a physical exam reveals a bump in the prostate. In those cases, a doctor might use the PSA to gather more information. If the PSA comes back high or if the PSA level, though still normal, has risen a lot, you may need a biopsy.

When you can wait and see. If you opted for the PSA test and it came back moderately high, you could have a repeat test before agreeing to a biopsy. It can also be a good idea to rule out infection by taking an antibiotic to see whether the PSA falls. If you did not opt for PSA screening but have symptoms that could be signs of cancer, consider a baseline PSA and undergoing biopsy if your PSA increases on a follow-­up test. You can also ask your doctor whether an MRI or ultrasound might provide more information.

You should know. In prostate biopsies, physicians usually take random specimens from the gland in an effort to get a representative sample. If the biopsy doesn’t find cancer, you may opt to repeat the PSA and biopsy a year or two later.

Find out more about what cancer tests you need or don't need.

Skin Cancer

Melanoma and other forms of skin cancer are on the rise. So it’s no surprise that skin biopsies account for about half of all biopsies, according to David Leffell, M.D., professor of dermatology at the Yale School of Medicine in New Haven. “It makes sense,” he says. “It’s the most accessible organ, and any number of physicians can do a biopsy.”

Who should be screened. Your doctor should periodically look over your skin for worrisome growths. And let your doctor know if you or someone close to you notices a mole that looks different from your others, a change to an existing one, or any other worrisome change.

When you need a biopsy. You usually need one if you have a sore that doesn't heal or that comes back and bleeds, Leffell says. Moles that itch or bleed should also be biopsied.

When you can wait and see. If you’re someone with a lot of moles, your doctor won’t want to have them all biopsied. Instead, she may photograph and follow them, or refer you to a practice with experts trained to track mole development.

You should know. Specialized pathologists called dermatopathologists read only skin biopsies and can better ­identify worrisome growths. Some dermato­pathologists use multiheaded microscopes, so several experts can look at the slide at the same time. “That’s important because not all cases of skin cancer are black and white,” Leffell says.

Thyroid cancer

More and more people are now receiving a diagnosis of this cancer, even though the number of people dying from it remains low. Experts suspect that there is no increase in the disease but that doctors are simply detecting it more often with imaging tests ordered for other reasons, such as CT scans of the head or chest. “Even if you weren’t looking for it, lo and behold, you find a thyroid nodule,” says Richard Wender, M.D., chief cancer control officer at the American Cancer Society.

Those nodules are easy to biopsy by needle, and some come back showing cancer. But most tumors found are not aggressive and are unlikely to harm you.

Who should be screened. There is no regular thyroid exam, but when you have a physical, your doctor can examine your thyroid by feeling the gland (in the front of your neck below the Adam’s apple).

When you need a biopsy. If you or your doctor detects a lump, she should order an ultrasound and blood test to check thyroid function. In general, a biopsy is a good idea when a nodule is larger than 1 centimeter or growing rapidly.

When you can wait and see. If the nodules are smaller than 1 centimeter without features that suggest a higher risk of cancer, discuss follow-up strategies with your doctor. Those may include a repeat physical exam, an ultrasound, or both, to make sure the nodule is not growing.

You should know. Most thyroid biopsies do not find cancer. But sometimes results can be inconclusive. In that case, ask your doctor about a new test that checks for genetic markers in the thyroid cells and can help with diagnosis.

Editor's Note:

This article also appeared in the August 2015 issue of Consumer Reports on Health.

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