Paul Sisson, San Diego Union-Tribune, Apr 12, 2017
Doctors' preferences appear to be winning out in the long-running debate about when screenings should begin for breast and prostate cancers.
Newly released survey results show that most physicians aren't following recommendations from the powerful U.S. Preventive Services Task Force for women to generally start getting mammograms at age 50. The health providers still have been approving the breast-cancer imaging procedure for women as young as 40.
The agency, whose guidelines are often followed by health insurance companies, this week also announced a new draft policy on prostate-specific antigen, or PSA, tests - the standard method for trying to detect prostate cancer in men. In doing so, it moved away from a 2012 recommendation that the diagnostic tool not be used for men 55 to 69 years old who have no symptoms or history of the disease.
As with mammograms, the task force saw that many doctors had continued to buck its standards, which are based on evidence gained from years of research and treatment for the overall U.S. population. With mammogram's it's important to note that other organizations, including the American Congress of Obstetricians and Gynecologists and the American Cancer Society, continue to recommend screening for women in their 40s.
The cancer-screening pendulum has been swinging back and forth over the years.
For decades, the medical establishment endorsed broad screening programs that encouraged mammograms for women starting at age 40 and PSA tests for men beginning on their 55th birthday. The idea was that these programs would catch lots of cases early and prevent deaths, but that hasn't happened. While cancer death rates have declined over time, prostate and breast cancers are still projected to kill a total of nearly 68,000 Americans this year, according to the National Cancer Institute and the American Cancer Society.
Broad-based screening has been criticized for catching tumors that may never pose a serious threat. In some cases, women have opted for double mastectomies after detection of very small breast tumors while thousands of men have undergone radiation therapy or significant surgeries after a PSA test detects cancer that, if left alone, would grow so slowly that it would never cause significant health problems.
Unnecessary or overly aggressive treatment is also expensive.
A 2015 study concluded that avoiding treatment of low-grade prostate cancer in Americans who would never die from the disease would save $1.32 billion per year. Meanwhile, the estimated cost of coping with mammogram false positives and other types of unnecessary care in breast cancer has been estimated at $4 billion per year.
At the same time, no one denies that screening really does save lives every day. The rub, then, is finding a way to catch potentially serious cases early while not overreacting to minor findings.
Dr. Alex Krist, a member of the U.S. Preventive Services Task Force, said the difficulty in cancer prevention is finding balance.
"We have to work based on solid evidence that is in the medical literature and make a decision based on the balance of benefits and harms," Krist said.
He said the agency's decision to propose a change in its rating for PSA tests, after advocating against them in 2012, reflects additional medical evidence that has appeared. For every 1,000 men who undergo the test, up to 230 will have a positive diagnosis of prostate cancer. But within that smaller group, as many as 120 people will turn out to have a false positive after a biopsy or other secondary diagnosis method.
The 1,000 PSA tests are expected to prevent at least one death, slightly higher than an estimate of zero to one death that was made in 2012. Five men would still be expected to die of prostate cancer despite the screening. Evidence also suggests that three men will avoid having their cancer spread to other parts of their body, which would increase their chance of dying, Krist noted.
Though new evidence shows only slightly enhanced benefits of PSA screening, Krist said it was nonetheless enough to push the recommendation toward doctor-and-patient consultations on a case-by-case basis.
"It's hard to judge. How many lives do you have to save to offset the false positives, overtreatment and overdiagnosis?" Krist said.
It's a judgement call, said Dr. Christopher Kane, chair of the urology department for the UC San Diego Health system who practices at the university's Moores Cancer Center.
He said there was definitely a time when too many men were undergoing surgeries that could leave them impotent or incontinent after receiving a PSA test with higher-than-normal values. But there have been significant recent strides in "active surveillance," where a doctor keeps monitoring a patient's prostate health rather than opt for immediate treatment, Kane added. If the cancer grows and becomes a threat, then the patient can opt for surgery.
Kane said the Moores center currently has about 400 prostate-cancer patients in San Diego County who are in the "active surveillance" category - and that many of them will live the rest of their lives without the disease ever becoming a deadly threat.
"We will follow them without treatment because, even over their lifetime, most will probably never progress," he said.
In his view, the problem was not really the PSA test itself but rather how patients and doctors reacted to it.
"Prostate cancer today almost exists as two different conditions. One is a normal component of aging and the other is a dangerous condition that kills thousands of men every year. The PSA test definitely has a role in helping us spot the more serious cases quickly," Kane said.
In breast cancer, the concern expressed by many studies has been that mammography screening doesn't result in significantly lower death rates from the disease. A comprehensive review of many breast cancer studies by the National Cancer Institute concluded that "screening for breast cancer does not affect overall mortality."
Early detection through a mammography, the institute said, saves the lives of between two and six women per 10,000 screened, while between 466 and 479 will suffer false positives or false negatives.
Acting on this research, the U.S. Preventive Services Task Force recommends mammography for women starting at age 50. But the results of a new survey, published in the journal JAMA Internal Medicine, suggests that most doctors are not heeding that advice. A full 81 percent continued offering mammograms for women beginning at age 40, the research found.
Dr. Anne Wallace, director of the Comprehensive Breast Health Center at UC San Diego Health, said that it doesn't surprise her that most doctors are not asking their patients to delay mammograms until they turn 50. She said most have treated patients in their 40s where a mammogram caught a serious case of breast cancer early.
But she added that the task force's guidelines have helped, giving doctors a citable source to introduce the notion that a positive mammogram result is not necessarily a big deal.
"It has enabled me to have a reasonable discussion instead of a frightened discussion," Wallace said.
Still, she said she and many other doctors do move forward to excise small tumors in the breast even though they may never grow or spread. She said taking them out earlier rather than later means less pain and worry for her patients.
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