It seems that it remains debatable whether screening women under 50 years old for breast cancer significantly reduces deaths from the disease.
In the latest study by British researchers it is suggested that annual mammograms beginning at the age of 40 will save only four lives for every 1,000 women screened.
Therefore say the researchers such a small benefit must be weighted against the increased radiation the women are exposed to, which could itself add to the breast cancer risk, and also create anxiety caused by false positive results.
Dr. Sue Moss of the Institute of Cancer Research in London says the trial did not find a significant reduction in breast cancer mortality in women offered annual screening between the ages of 40 and 48 years.
Those results are consistent with the findings of previous studies which compared the risks and benefits of screening women under 50 years old for breast cancer.
Breast cancer is the leading cause of cancer in women, and most commonly occurs in women over 50.
According to the World Health Organization, more than 1.2 million people will be diagnosed with breast cancer this year worldwide.
The American Cancer Society estimates that about 213,000 women in the United States will be diagnosed with invasive breast cancer each year and 40,970 women will die.
In Britain women aged 50-70 years old are invited for annual screening while in some countries such as the U.S. annual screening begins at 40.
Dr. Moss and her team examined the impact of screening younger women for an average of 11 years; they randomly selected 160,900 British women to have annual mammograms from age 40 or from age 50.