Mammograms Important for Women in Their 40s — Despite Recommendation from National Task Force

Dr_Brett_Parkinson_Breast_Cancer_Screenings_age_40

The Task Force’s recommendations for screening do not reflect the science behind the issue, specifically its own research based on such esteemed organizations as the Cancer Intervention and Surveillance Modeling Network (CISNET), the Breast Cancer Surveillance Consortium (BCSC) and its own previous meta-analysis of multiple, randomized controlled clinical trials. 

However, the Task Force has not acted appropriately on this knowledge, instead making value judgments that are not scientifically based on the relative harms and benefits of screening. Specifically, it has overestimated the rate of over-diagnosis, has inappropriately defined a false positive examination, and has exaggerated the harms, psychological and physical, of being recalled from a screening study. 

As in 2009, the Task Force does not recommend routine screening of women 40-49, and recommends every-other year screening in women ages 50-74. Nor does it recommend screening women over 75, presumably because women in that age group were not included in the original screening trials.

After a thorough review of the Task Force’s draft recommendations, these are the three areas I feel the Task Force failed to take into account.

Over-diagnosis

  • The Task Force failed to take into account that the baseline incidence of breast cancer has been increasing since 1940. Between 1940 and 1982, the incidence increased 1% per year. This was before screening was widely available. The estimates of “over-diagnosis” do not take this into account, nor of the fact that the incidence continues to increase. This falsely elevated the supposed number of over-diagnosed cases.
  • There is no scientific way of knowing which breast cancers will progress to lethality. Although not all in-situ cancers will develop into invasive cancers, there is no evidence that invasive cancers will not grow, or even as some have suggested, regress.

False Positive

  • Most of what the Task Force refers to as “false positives” are simply call-backs for additional testing from an abnormal, but not necessarily positive, screen.  Approximately, 10% of patients are called back for additional tests. Eighty-five percent of the time, the supplemental studies are non-invasive, consisting of additional mammographic views or ultrasound. Only about 15% of patients recalled from a screening examination undergo a needle biopsy, and 20-40% of those represent cancer.  Rarely do women undergo surgery for diagnosis. 

Harms

  • Although a recent study in JAMA in 2014 showed women experienced anxiety over a false-positive test result, it was short-lived and resulted in no long-term damage to emotional or physical health.
  • The physical harms are minimal, and only if a biopsy is done. There is a small risk of bleeding and infection. The risks are not life-threatening, unlike other diagnostic procedures.
  • Any risk for the subsequent development of a radiation-induced cancer is very small.
  • The risks of physical harms from overtreatment are only theoretical. 

I’ve compiled a list of facts about breast cancer, screenings, and detection.

  • The death rate from breast cancer has dropped 35% since the widespread use of screening mammography in the late 1980’s.
  • 40% of the years of life lost to breast cancer are in women diagnosed while in their forties.
  • One in six breast cancers are diagnosed in women aged 40-49.
  • Even in the Task Force’s own tables, 4 deaths can be avoided if 10,000 40-49 year-old women are invited to screen over 10 years; 8 deaths in the 50-59 year-old age group; 21 in the 60-69 year-old group; and 13 in the 70-74 year-old group. 
  • “Invited to screen” is not the same as really undergoing screening. If we take into account women in the randomized controlled clinical trials that were actually screened, the number of lives saved dramatically increases.  Women who choose not to be screened  who are assigned to the screening arm of an randomized controlled clinical trials, who develop late-stage breast cancer, are still counted in the screened group, which does not reflect the true benefit of screening.
  • Screening mammography decreases the death rate from breast cancer by at least 30% in women who are “invited to screen.” In the Swedish Observational studies, the screened group had a mortality reduction of over 40%.
  • Not only are deaths avoided by screening, but early detection results in less invasive treatment with surgery, radiation and chemotherapy.
  • Screening annually vs. biennially decreases mortality by approximately 25%.
  • According to a recent study in the American Journal of Roentgenology by Hendrick and Helvie, if women age 40-49 are not screened, and screening is conducted only biennially in the 50-74 year-old age group, there would be an additional 6,500 deaths in the United States.
  • In a major recent study from the Harvard Teaching Hospitals, 70% of the women who died from breast cancer in their 40s were among the 20 percent of women who chose not to be screened.

The Task Force did not address the harms of not screening, which are substantial, and include increased morbidity of advanced breast cancer and death. In addition, it did not offer insights into the approach that was used to balance the benefits of screening against the harms. 

Moreover, it did not adhere to the Institute of Medicine’s recommendations for guideline development. There were no breast cancer experts on the panel, there was no transparency in the behind-the-doors meetings and the public comment process, and it did not adhere to the Administrative Procedure Act, which would have engaged experts and patients in a significant way. No such experts were consulted.