By David Liu, Ph.D.

Saturday Sept 24, 2011 (foodconsumer.org) -- When it comes to breast cancer, more screenings may not necessarily result in lower death risk from the disease.  A new study published in the Sept 20 2011 issue of British Journal of Cancer found among women aged 40 to 49 years, those who received annual mammogram screening had the same death risk from breast cancer as those who received the procedure triennially.

I Parvinen in Health Office of City of Turku in Finland had followed two groups of women aged 40 to 49 years for ten years for incident breast cancer cases and for additional three years for the death rates.  Since 1987, the city invited women born in even calendar years to receive mammography screening annually and women born in odd years to receive the screening triennially.

Of 14,765 women who were free of breast cancer at 40, 207 were diagnosed with the disease before they reached 50. Of the patients, 36 died of breast cancer.

Parvinen et al. found the incidence of breast cancer among those receiving mammography screening was similar to that among those receiving the screening triennially.  Actually incidence for the former was 12 percent lower compared to the latter. But the difference was not significant.

The mortality of breast cancer in women receiving the annual mammogram screening was actually 20 percent higher, compared to women who receive triennial mammography screening. But the difference was not significant.

The authors concluded that "there were no differences in the incidence of breast cancer or incidence-based breast cancer mortality between the women who were invited for screening annually or triennially."

Breast cancer screening by itself can damage breast cancer increasing risk of breast cancer because the procedure is based on x-ray, which is recognized by the U.S. National Toxicology Program as a cancer-causing agent.   The screening can lead to false positive diagnosis or over diagnosis, resulting in unnecessary intrusive treatment, anxiety and financial loss.

But the medial circle believes that the benefits overweign the risks.  Mammogram screenings can help diagnose breast cancer early.  And some studies found early diagnosis which naturally often lead to early treatment was associated with a better survival.  But few studies if any demonstrated that the higher survival rate was due to the treatment, but not because of the early diagnosis.   

A health observer suggested that early diagnosis in itself can result in a better survival even without any treatment.  This is so because doctors start counting the 5-year survival from diagnosis.

Breast cancer is diagnosed in more than 175,000 women in the United States each year and the disease and complications from treatment and disease per se kill about 50,000 annually in the country, according to cancer.gov.