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Cheaper Cancer Tests Carry Risks As Well As Benefits

A consumer friendly breast cancer test, introduced Tuesday, offers women new ways to assess their risk at a very low cost. But it also raises the possibility of over-diagnosis and unnecessary treatment.

The test, offered by a company named Color Genomics, will cost $249, far less than the usual $1,500 or so. It will screen for BRCA, a gene whose mutations are linked to increased risk of breast and ovarian cancer. Twenty to 25 percent of breast cancer that runs in families and 5 to 10 percent of all breast cancer cases are attributable to BRCA.1

Thirty-five to 55 percent of women with BRCA mutations will never develop cancer, but once a woman receives a positive genetic test, she may choose to schedule more frequent mammograms, take hormone therapy or undergo prophylactic mastectomies or oophorectomies (removal of ovaries). Angelina Jolie chose to have both those kinds of pre-emptive surgeries after she saw her suspicions about her family history confirmed with a test. For some women, these choices will be life-saving, but for others, they could be unnecessary.

Color Genomics’s BRCA screening test is the cheapest and least invasive to come to market, the fruits of the Supreme Court’s 2013 ruling that genes could not be patented.

The company requires a doctor to formally request every screening ordered by a customer, but those doctors will frequently be acting against the recommendations of the American Academy of Family Physicians and the United States Preventive Services Task Force, both of which have specifically recommended that BRCA testing not be done for women without a family history of breast or ovarian cancer.

Technically, in fact, BRCA testing isn’t even recommended for women who do have a family history, at least not as the first step. Ideally, a woman with cancer in her family will have a relative with cancer tested first so that a genetic counselor can identify which mutation, if any, the family carries and then test asymptomatic relatives only for that variant, to reduce the risk of a false positive.

False positives for BRCA mutations are rare, but they carry a heavy risk. A false positive on a mammogram puts a woman at risk of an unnecessary biopsy and increased screening in the future. Mammograms also detect many things that look like cancer but will never cause the woman any harm, and when these indolent cancers or pre-cancers are detected, women may receive treatments that they never needed.

For many women, the risk of a false positive mammogram test outweighs the benefits of screening. A false BRCA result could have even more invasive consequences if a woman chooses to have a prophylactic mastectomy or other surgical interventions.

The benefits that do result from increased BRCA screening won’t just accrue to women like Jolie. Testing can help women from high-risk families who receive negative BRCA tests and can therefore reduce screening, reducing the risk of false positives and unnecessary treatment. A 2008 study of women from families with BRCA mutations who did not carry the mutation themselves found that these BRCA-negative women had essentially the same risk of cancer as women from families without mutations and should be screened in the same way.

Unfortunately, Color Genomics’s low price for BRCA testing is likely to be most attractive for women who are in least need of genetic screening. Under the Affordable Care Act, also known as “Obamacare,” BRCA tests are classified as preventive care for women with a family history of breast, ovarian, tubal or peritoneal cancer and must be fully paid for by insurers. Only women who are not at risk or women who don’t know they have a cheaper option are likely to choose Color Genomics’s services.

Opting in to unnecessary cancer screening is likely to be costly to consumers, however low the price of the test itself.

Footnotes

  1. Although this article uses “women” as shorthand, the risk of breast cancer and BRCA mutations is also relevant to all people considered female at birth.

Leah Libresco is a former news writer for FiveThirtyEight.

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