After 10 years of mammograms, a woman may get more harm than good from the screening, researchers from the U.K. found.
When false positive diagnoses and unnecessary surgeries were taken into account, the quality-adjusted life years (QALYs) gained were significantly reduced, James Raftery, PhD, of the University of Southampton, and colleagues reported online in BMJ.
"Inclusion of the harms from false-positive results and unnecessary surgery reduced the benefits of screening by about half, with negative net QALYs in the early years after the introduction of screening," they wrote.
In 1986, the Forrest report led to breast screening in the U.K., suggesting it would reduce the death rate from breast cancer by almost a third, and with few harms and at low cost.
Since then, a number of harms associated with screening have been acknowledged, particularly false positives and overdiagnosis of cancers that would never have caused symptoms. Also, a recent Cochrane review noted that mortality reductions may be smaller than initially expected, the researchers said.
So to assess the potential benefits of screening in terms of QALYs when those harms were included, Rafferty and colleagues looked at data from eight trials involving 100,000 women from the U.K., ages 50 and up, who had breast screening.
They found that taking the effects of those harms into account reduced the estimate of net cumulative QALYs gained after 20 years by more than half, from 3,301 to 1,536.
And when they changed the reduction in mortality from that suggested by the Forrest study to that suggested by the recent Cochrane review, the net QALYs at year 20 fell to 834, they reported.
That also generated negative QALYs for the first seven years of screening, and only 70 QALYs after 10 years, they reported.
Indeed, in sensitivity analyses, the results persisted, especially up to 10 years, suggesting that screening may have caused net harm, they reported.
"Our study supports the suggestion ... that mammographic breast cancer screening could be causing more harm than good after 10 years," they wrote. After that, net QALYs accumulate, but are much lower than would be expected, they added.
Means of reducing the harms from screening might include less frequent screens, particularly for younger women, the researchers said.
The study was limited because it relies on older clinical trial data regarding mortality and surgery and because the researchers didn't include information on recurrence and or re-operations.
Raftery and colleagues wrote that more research is needed on the extent of unnecessary treatment and its impact on quality of life. Further study should also focus on identifying patients who stand to benefit most from surgery, they added.
"From a public perspective, the meaning and implications of overdiagnosis and overtreatment need to be much better explained and communicated to any woman considering screening," they concluded.
We have to spend more time thinking about and applying strategies the REDUCE the risk of BC and PREVENT the incidence. Carole Baggerly Interview/Breast Cancer
Abstract
We sought to compare the molecular signature of node negative cancers from two cohorts 15 years apart, to determine if there is molecular evidence of increase in low and ultralow risk cancers over time.
We studied the impact of age, time period of diagnosis, and mammographic
screening on biology of tumors where The Netherlands Cancer Institute 70-gene prognosis signature was generated as part of 2 validation series, one retrospective (1984�1992), Cohort 1, and one prospective (2004�2006),
Cohort 2. A total of 866 patients were analyzed.
Regardless of time period of diagnosis, the proportion of T1, grade 1, hormone receptor positive (HR) tumors, and good prognosis by 70-gene signature significantly increases as age increases (P\0.01).
In women aged 49�60, the time period of diagnosis significantly affects the proportion of cancers that were NKI 70-gene low risk: 40.6% (67/165) compared with 58% (119/205) for Cohorts 1 and 2, respectively.
This is in contrast to the absence of a significant change for women
under age 40, where 25% (17/68) and 30% (17/56) were low risk in Cohorts 1 and 2, respectively. In women aged 49�60, using an ultralow risk threshold of the 70-gene signature, 10% of tumors in Cohort 1 were ultralow risk compared with 30% for women with screen-detected cancers in
Cohort 2. Older age and method of detection (screening) are associated with a higher likelihood of a biologically low risk tumor.
In women over age 50, biologically low risk tumors are frequent and tools that classify risk may minimize overtreatment.
Abstract OBJECTIVE:
To examine the relationship between guideline panel members' conflicts of interest and guideline recommendations on screening mammography in asymptomatic, average-risk women aged 40-49 years.
STUDY DESIGN AND SETTING:
We searched the National Guideline Clearinghouse and MEDLINE for relevant guidelines published between January 2005 and June 2011. We examined the disclosures and specialties of the lead and secondary authors of these guidelines, as well as the publications of the lead authors.
RESULTS:
Twelve guidelines were identified with a total of 178 physician authors from a broad range of specialties. Of the four guidelines not recommending routine screening, none had a radiologist member, whereas of the eight guidelines recommending routine screening, five had a radiologist member (comparison of the proportions, P=0.05). A guideline with radiologist authors was more likely to recommend routine screening (odds ratio=6.05, 95% confidence interval=0.57-∞, P=0.14). The proportion of primary care physicians on guideline panels recommending routine vs. nonroutine screening was significantly different (38% vs. 90% of authors; P=0.01). The odds of a recommendation in favor of routine screening were related to the number of recent publications on breast disease diagnosis and treatment by the lead guideline author (P=0.02).
CONCLUSION:
Recommendations regarding mammography screening in this target population may reflect the specialty and intellectual interests of the guideline authors.
May also reflect direct financial interest as well?
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