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Archive for Tuesday, June 15, 2010

Not all tumors are equal, and some treatments too aggressive

June 15, 2010

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— D.J. Soviero wanted the least treatment that would beat back her small, early-stage breast cancer, but her first doctor insisted she had only one option: tumor removal followed by radiation and chemotherapy.

Then she found a novel program at the University of California, San Francisco, that gave her an unbiased evaluation of the pros and cons of all treatment options.

“I realized that I didn’t need to use a sledgehammer. It was my choice,” said Soviero, of San Francisco, who went with the lumpectomy and radiation, but refused the chemo.

It’s an unthinkable notion for a generation raised on the message that early cancer detection saves lives, but specialists say more tumors actually are being found too early. That is raising uncomfortable questions about how aggressively to treat early growths — in some cases, even how aggressively to test — along with a push for more of the informed-choice programs such as the one Soviero used.

“The message has been, ‘Early detection, early detection, early detection.’ That’s true for some things but not all things,” said Dr. Laura Esserman, a breast cancer specialist at UCSF. She helped lead a study, reported last week, that found mammography is increasing diagnoses of tumors deemed genetically very low risk.

“It’s not just all about finding any cancer. It’s about being more discriminating when you do find it,” she added.

Tumor detection

Today’s cancer screenings can unearth tumors that scientists say never would have threatened the person’s life. The problem is there aren’t surefire ways to tell in advance which tumors won’t be dangerous — just some clues that doctors use in prescribing treatment.

Work is under way to better predict that, and even the staunchest supporters of screening call overdiagnosis a problem that needs tackling.

“We’re really at a tipping point right now, where we have a trade-off between the benefits of finding cancer early and the harms that are caused,” said Dr. Len Lichtenfeld of the American Cancer Society. “We treat more patients than we know will benefit. … We just don’t know who they are.”

Nowhere is the disconnect more obvious than with prostate cancer screening. Most men over 50 have had a PSA blood test to check for it even though major medical groups don’t recommend routine PSAs, worried they may do more harm than good for the average man.

What’s the evidence? A study of 76,000 U.S. men, published last year, concluded annual PSAs didn’t save lives. A separate study estimated two of every five men whose prostate cancer was caught through a PSA test had tumors too slow-growing ever to be a threat.

A European study of 162,000 men screened less aggressively — a PSA every four years versus none — found seven fewer deaths per 10,000 men screened. But 48 men had to be treated to prevent each death, meaning many men who weren’t facing death experienced treatment that can have such side effects as incontinence and impotence.

Thus, the American Cancer Society urges that men weigh the limitations of PSAs against their individual risk and fear of cancer before deciding for themselves. Government guidelines say men over 75 shouldn’t get a PSA at all — although about one-third do.

“PSA is the controversy that refuses to die,” said Dr. Michael Barry of Massachusetts General Hospital and the Foundation for Informed Medical Decision-Making, which pushes programs that help patients make such choices. “But in some ways, it’s the prototypical close call that we have to come to grips with in American medicine — that there just isn’t one right answer for everybody.”

Unnecessary biopsies

Mammograms aren’t nearly as controversial, except for the when-to-start-them question. Most medical groups advise age 40; a government task force ignited complaints last year by advising not until 50. Generally, studies find they cut the risk of death from breast cancer by roughly 20 percent.

The trade-off: More than three-quarters of the 1 million-plus anxiety-provoking biopsies done each year to check out suspicious spots turn out to have been false alarms.

The bigger unknown is overdiagnosis, as closer mammogram readings spot ever-earlier growths.

A study in last month’s Journal of the National Cancer Institute said nearly one-quarter of breast tumors found by mammograms may be overdiagnosed. That includes invasive cancer, but also a common milk-duct growth called DCIS, or ductal carcinoma in situ.

DCIS isn’t invasive cancer and isn’t life-threatening; it’s described as “stage zero” cancer or even pre-cancer. But it is a risk factor for later developing invasive disease, and many of the 50,000 DCIS cases a year get the same care as women with outright early cancer.

Research is examining when and how to scale back aggressive DCIS care. At UCSF, Dr. Shelley Hwang is testing whether hormone drugs such as tamoxifen allow DCIS patients to avoid surgery altogether.

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