An intriguing new study found that the vast majority of deaths from breast cancer occur among women who didn't have routine mammography. The report, published in the journal Cancer, applied "failure analysis" -- a way, typically used in engineering to see what might have gone wrong -- to expose possible factors in women's deaths. There was a striking find. Among patients who were 40-49 years old at the time of a stage I, II or III invasive breast cancer diagnosis, 77 percent who died of the disease hadn't had regular screening.
The paper's method is flawed, and conclusions limited. But sometimes an imperfect study can hint at real insights. In this report, the apparent concentration of deaths among middle-aged women who "opted out" from screening and had breast cancer suggests that that not having a mammogram is a risk factor for dying from the disease. The new findings are consistent with the view, or model that was once a tenet in oncology, that early detection matters in breast cancer survival.
The researchers evaluated records of 7,301 breast cancer patients with charts at the Massachusetts General or Brigham and Women's Hospital in Boston. The cases were detected between 1990 and 1999. Women's deaths were noted in medical charts, Massachusetts and National Death Registries through 2007. This study, with a focus on screening, omits mention of male breast cancers. The investigators honed in on women with invasive Stage 1, 2 or 3 disease -- stages when breast cancer is clearly malignant but hasn't yet spread. It's at these levels, precisely, when screening could make all the difference. That's because once a woman has metastatic (Stage 4) breast cancer, early detection is no longer relevant. And by not including DCIS (Stage 0) or pre-malignant conditions, the authors avoid exaggerating a possible benefit of mammography.
The investigators identified 609 patients who died from breast cancer. It was this group -- women with limited-stage, invasive breast cancer who later succumbed to the malignancy -- that formed the basis of the "failure analysis." Only 118 (19 percent) of women who died from breast cancer had tumors detected upon regular screening. Sixty women, nearly 10 percent of the group, felt or otherwise found cancer between regular screens; these lethal "interval tumors" represent screening failures. Overall, 71 percent of the breast cancer deaths occurred in women who had no screening or irregular mammography, defined as an interval of greater than two years between tests.
Not surprisingly, the breast cancer deaths occurred disproportionately in younger women. The median age at finding breast cancer for all patients in the study was 55 years, but for those who died from the disease it was 49 years. Among those women who died of other causes, the median age at diagnosis was 72 years. One point that did draw my attention is that over 25 percent of the cases, lethal and otherwise, fell into the 40-49 year age bracket at diagnosis. That's a lot of invasive breast cancer in women who are in the midst of life, and a huge number of possibly preventable deaths.
Where I'll go with this is to ask my readers -- patients and doctors, oncologists and primary care physicians, health care policy makers and economists, reporters and editors, whoever's in a position to act upon this news -- to consider the possibility that mammography, done right, can save lives. Keep an open mind, and realize that most published studies on breast cancer screening are flawed, too, by their observational, retrospective or meta-analytical natures.
Please don't tire of this topic. Breast cancer remains a leading killer of middle-aged women. Getting a tumor out before it has metastasized can, still, make the difference between a small surgery and limited treatment vs. life-long therapy for an incurable condition. Early detection affects the quality of women's lives. The costs of failed detection, and late diagnoses, are great.
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