The cancer tests you really need—and those you don't

A few years ago women were usually told to get annual mammograms starting at age 40 and men were told that the PSA blood test for prostate cancer was a lifesaver. Now the U.S. Preventive Services Task Force, whose advice helps set government policy on screening tests, says that women should start breast cancer screening every two years at age 50 and that men can skip the PSA test. And the list of tinkers, tweaks, and about-faces on cancer screening keeps getting longer. For example:

• The American Gastroenterological Asso­ciation warns that though colon­oscopy saves lives from colorectal cancer, some people get tested more often than necessary, exposing themselves to unnecessary risks.
• A Medicare advisory panel in April said that the agency should not cover lung cancer screening even in high-risk people—contradicting earlier advice from the Task Force.
• A study published online in May by the journal Cancer found that cervical cancer may be more common than previously thought, especially in older women, prompting its authors to question advice that most women can stop Pap tests after age 65.
• Minnesota became the latest of more than a dozen states to pass a law requiring that women be told whether they have “dense breasts” after a mammogram—even though experts disagree on what’s best for women who get that news.

Why is it all so complicated? We talked with experts, reviewed current research, and came up with our advice on the screening tests you need and those you don’t—at least for now.

Colonoscopy saves lives but does pose risks, including bleeding and punctures of the colon, so it shouldn’t be done more often than necessary. For many people, that’s once per decade. But some doctors recommend it more often. And a Consumer Reports survey of more than 10,000 subscribers 50 and older found that only about a third of people screened for the cancer were told about test complications, and only 10 percent of those who had colonoscopy or sigmoidoscopy were told about simpler, less invasive options.

CR’s take: People ages 50 to 75 should get screened for colorectal cancer. If a colonoscopy doesn’t find cancer or precancerous polyps, you can usually wait a decade for your next test. If one or two small polyps are found, get a repeat test in 5 to 10 years. If you have more serious polyps or are at high risk, ask your doctor whether you need more frequent tests. Also ask about alternatives: sigmoidoscopy (exam of the lower third of the colon) every five years plus a stool test every three years; or a stool test every year.

Read more about when you need colonoscopy (PDF) and how to prevent colon cancer.

In 2012 the Task Force and other groups, including the American Cancer Society, said that many women could go several years between Pap tests and most could stop after 65. The new study raised questions about that advice. It found that some research had underestimated the cancer’s incidence by failing to take into account those who have had a hysterectomy that removes the cervix along with the uterus, eliminating the risk of cervical cancer. But our experts say that finding doesn’t warrant a return to routine screening after 65. Even adjusted for hysterectomy, the cancer is uncommon in older women who were regularly screened and had no abnormal results, says the American Cancer Society, and the tests aren’t as accurate in them.

CR’s take: Women 21 to 30 should have a Pap test every three years. Those ages 30 to 65 can go five years between tests if they have a human papillomavirus test at the same time to check for the virus that can cause the cancer. Women older than 65 with a history of normal test results don’t need retesting.

Read more about cervical cancer screening (PDF).  

Women with dense breasts—that is, who have relatively little fat in their breast tissue—face a greater breast cancer risk, in part because mammography is less accurate in them. That has led activists to lobby states for laws requiring that women are told whether their mammogram shows dense breasts. The hope is that those women could then discuss undergoing other tests that may improve detection.

But the American College of Radi­ology says that an ultrasound or MRI, possible supplemental tests, are more likely to raise false alarms. And no good studies show that adding them or tomosynthesis (3D mammography) saves lives.

CR’s take: We agree that women have the right to know about their breast health, but we think they should also know the limitations of ultrasound and other tests. They may make most sense for women with “extremely dense” breasts, who might have about twice the risk of breast cancer compared with women with average density. In general, we agree with the Task Force that women ages 50 to 74 should have mammograms every two years. We think women in their 40s and those 75 and older should talk with their doctor to see whether the benefits outweigh the potential harm for them.

Read more abou the imaging tests you might need if you are diagnosed with breast cancer (PDF).  

In 2013 the Task Force recommended annual low-dose CT scans for certain long-term heavy smokers after a study found that it cut the risk of death from the disease by 16 percent in that group. Under the Affordable Care Act, most private insurers must cover tests recommended by the Task Force. So the news that a Medicare panel advised against it came as a surprise, especially because it meant people might lose coverage at 65—when lung can­cer risk increases. That prompted more than 40 groups to say that Med­icare should reject the advisory pan­el’s advice.

CR’s take: Our experts agree that Medicare should cover the test. But they emphasize that it should be used only for those ages 55 to 80 who smoked a pack per day for 30 years or two packs per day for 15 years, and either currently smoke or stopped within the last 15 years.

Read more about lung cancer screening.

Many men get their PSA measured despite a growing consensus that it’s usually not necessary. For example, the Amer­ican Academy of Family Physicians advises against routine screening.

CR’s take: Men should not routinely get a PSA test, especially if they are younger than 50 or older than 74. If you are between those ages, talk with your doctor about the risks and benefits of the test, and your risk factors, such as being African-American or having a brother, son, or father who had the disease.

Read more about prostate cancer screening and the tests you might need if you are diagnosed with prostate cancer (PDF).

Experts remain stymied by this cancer because use of the available tests—ultra­sound and a blood test called CA-125—have not been linked to a reduced risk of dying of the disease.

CR’s take: Women with risk factors—such as a family history of ovarian or breast cancer and those who carry the BRCA1 and BRCA2 genes—could consider the tests. Also talk with your doctor if you have abdominal pain or bloating, difficulty eating or feeling full quickly, or unusual vaginal bleeding, which can suggest cancer.  

Some doctors and imaging centers advertise “whole body” scans, tests that promise to do a “Star Trek”-like check of your entire body for cancer. They are done with a CT scan, which uses multiple X-rays, sometimes combined with positron emission tomography (PET) scans, which involve injecting you with a radioactive material that can be traced as it travels through your body. But the Society of Nuclear Medicine and Molecular Imaging, a group that represents specialists in the field, warns that the PET/CT combination is far more likely to lead to false alarms and unnecessary exposure to radiation than to spot cancer in healthy adults. And other research suggests similar problems for whole-body CT scans alone.

This article also appeared in the August 2014 issue of Consumer Reports on Health.

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