Featured Research

from universities, journals, and other organizations

Breast cancer screening reduces deaths, study shows

Date:
June 17, 2014
Source:
BMJ-British Medical Journal
Summary:
Invitation to modern mammography screening may reduce deaths from breast cancer by about 28 percent, suggests a study. This means that for every 10,000 women invited to screening, about 27 deaths from breast cancer might be avoided during their lifetime.

Invitation to modern mammography screening may reduce deaths from breast cancer by about 28%, suggests a study from Norway published on bmj.com. This means that for every 10,000 women invited to screening, about 27 deaths from breast cancer might be avoided during their lifetime.

An accompanying editorial says this study largely confirms what is already known -- that the benefits of breast screening "are modest at best" -- and calls for women to be given balanced information including the screening harms of overdiagnosis, psychological stress, and high healthcare costs.

Randomised trials from the 1970s and 80s suggested that mammography screening prevents deaths from breast cancer. But the methods used by some of these studies have been criticised, and this has raised doubts about the validity of the findings. Advances in technology and treatment has also led to questions about the reliability of older trials to estimate the benefits and harms of modern day screening.

So researchers in Norway set out to evaluate the effectiveness of modern mammography screening by comparing the effects on breast cancer mortality among screened and unscreened women.

They analysed data from all women in Norway aged 50 to 79 between 1986 and 2009 -- the period during which the Norwegian mammography screening programme was gradually implemented. They compared deaths from breast cancer among women who were invited to screening with those who were not invited, making a clear distinction between cases of breast cancer diagnosed before (without potential for screening effect) and after (with potential for screening effect) the first invitation for screening.

They also used a simulation model to estimate how many women aged 50-69 years would need to be invited to screening every two years to prevent one breast cancer death during their lifetime.

Based on more than 15 million person years of observation, breast cancer deaths occurred in 1,175 of the women invited to screening and in 8,996 of the women who were not invited.

After adjusting for factors such as age, area of residence, and underlying trends in breast cancer mortality, the researchers estimate that invitation to mammography screening was associated with a 28% reduced risk of death from breast cancer compared with not being invited to screening. The screening effect persisted, but gradually declined with time after invitations to screening ended at 70 years of age.

Using the simulation model, they also estimate that 368 women aged 50-69 would need to be invited to screening every two years to prevent one death from breast cancer during their lifetime. Further analysis to test the strength of the findings did not substantially change the results.

"In our study, the estimated benefit for breast cancer mortality (28%) associated with invitation to mammography screening indicates a substantial effect," say the authors. But evolving improvements in treatment "will probably lead to a gradual reduction in the absolute benefit of screening," they conclude.

This study "adds important information to a growing body of observational evidence estimating the benefits and harms of screening," say US researchers in an accompanying editorial, and should "make us reflect on how to monitor the changing benefits and harms of breast cancer screening." They call for women to be given balanced information to help them make informed decisions about screening.


Story Source:

The above story is based on materials provided by BMJ-British Medical Journal. Note: Materials may be edited for content and length.


Journal References:

  1. H. Weedon-Fekjaer, P. R. Romundstad, L. J. Vatten. Modern mammography screening and breast cancer mortality: population study. BMJ, 2014; 348 (jun17 17): g3701 DOI: 10.1136/bmj.g3701
  2. J. G. Elmore, R. P. Harris. The harms and benefits of modern screening mammography. BMJ, 2014; 348 (jun17 20): g3824 DOI: 10.1136/bmj.g3824

Cite This Page:

BMJ-British Medical Journal. "Breast cancer screening reduces deaths, study shows." ScienceDaily. ScienceDaily, 17 June 2014. <www.sciencedaily.com/releases/2014/06/140617210843.htm>.
BMJ-British Medical Journal. (2014, June 17). Breast cancer screening reduces deaths, study shows. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2014/06/140617210843.htm
BMJ-British Medical Journal. "Breast cancer screening reduces deaths, study shows." ScienceDaily. www.sciencedaily.com/releases/2014/06/140617210843.htm (accessed July 31, 2014).

Share This




More Health & Medicine News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Health Insurers' Profits Slide

Health Insurers' Profits Slide

Reuters - Business Video Online (July 30, 2014) Obamacare-related costs were said to be behind the profit plunge at Wellpoint and Humana, but Wellpoint sees the new exchanges boosting its earnings for the full year. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Concern Grows Over Worsening Ebola Crisis

Concern Grows Over Worsening Ebola Crisis

AFP (July 30, 2014) Pan-African airline ASKY has suspended all flights to and from the capitals of Liberia and Sierra Leone amid the worsening Ebola health crisis, which has so far caused 672 deaths in Guinea, Liberia and Sierra Leone. Duration: 00:43 Video provided by AFP
Powered by NewsLook.com
At Least 20 Chikungunya Cases in New Jersey

At Least 20 Chikungunya Cases in New Jersey

AP (July 30, 2014) At least 20 New Jersey residents have tested positive for chikungunya, a mosquito-borne virus that has spread through the Caribbean. (July 30) Video provided by AP
Powered by NewsLook.com
Xtreme Eating: Your Daily Caloric Intake All On One Plate

Xtreme Eating: Your Daily Caloric Intake All On One Plate

Newsy (July 30, 2014) The Center for Science in the Public Interest released its 2014 list of single meals with whopping calorie counts. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

    Environment News

    Technology News



      Save/Print:
      Share:

      Free Subscriptions


      Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

      Get Social & Mobile


      Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

      Have Feedback?


      Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
      Mobile: iPhone Android Web
      Follow: Facebook Twitter Google+
      Subscribe: RSS Feeds Email Newsletters
      Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins