A new US study published in the journal Cancer reports a disturbing trend across the country. Fewer women are going for mammography screening exams to detect early stage breast cancer.

Jane, a 40 or 50 year old American woman takes out the letter for the second time. It’s an invitation from the clinic to come in for her mammography screening exam. She remembers the last one. Taking a half day off work, traipsing a long way to the clinic, nowhere to park, waiting for ages, then the discomfort as her breasts were squashed between two cold metal plates one at a time. Didn’t she read recently that breast cancer rates were falling? Perhaps it’s not so important after all. “I’ll think about it later,” she decides, stuffing the letter down the side pocket of her purse. That was six months ago; in the meantime other seemingly more important things have stolen Jane’s time and attention.

Is this story typical? Are mammograms now seen by American women as less important than before? If not, then what is the reason for the fall in mammography rates across the nation?

This question is being asked by health professionals who are concerned about a disturbing recent trend among older women right across America.

A new study, to be published in the June 15th paper edition of Cancer, a peer-reviewed journal of the American Cancer Society, shows that screening mammography rates for breast cancer in the US dropped by 4 per cent between 2000 and 2005.

While there have been studies suggesting that mammography rates are levelling off or falling in some parts of the US, this is the first study to show that the decline is nationwide and affects women for whom the mammogram exam is intended to reduce their mortality risk.

Dr Nancy Breen from the National Cancer Institute and colleagues reviewed records from the National Health Interview Survey and found that between 1987 and 2000, there was a steady rise in mammography screening tests on women over 40, but after that the rates levelled off. And from 2000 to 2005 they fell by 4 per cent.

The drop in mammography screening was most pronounced for women over 50, with the sharpest drop being reported for the 50 to 64 year olds, and women in higher socioeconomic groups, both of which had previously shown much higher screening rates.

The timing of this trend is coincident with a drop in the reported levels of new breast cancer diagnoses. After seeing year on year increases, newly diagnosed breast cancer cases have started falling in the US. What is not known is how this relates to the decline in mammography rates.

Mammography is the most effective and most used method of detecting tumours in breast tissue, and potentially finds cancerous tumours early before the cancer has spread.

The widespread use of mammograms since the 1980s for screening women over 40 years of age in the US has been seen by scientists as the main reason behind the reduction in deaths due to breast cancer. Between 1987 and 2000 the screening rate went up from 39 to 70 per cent among women over 40.

Dr Breen and her colleagues are concerned, as are many other health professionals, “that some of the observed decline in incidence may be due in part to the leveling off and reduction in mammography rates”.

They recommend that the situation is monitored carefully, and the underlying factors in particular, to see how the decline in mammography is linked to the decline in newly diagnosed breast cancers. If the latter is caused by the former, then this could show up in years to come as an increase in late stage diagnosed breast cancers, and the unwelcome consequences of higher mortality rates. Also, if these downward trends in early detection and screening continue, then new intervention will be needed, they said.

“Reported Drop in Mammography: Is This Cause for Concern.”
Nancy Breen, Kathleen A. Cronin, Helen I. Meissner, Stephen H. Taplin, Florence K. Tangka, Jasmin A. Tiro, and Timothy S. McNeel
Cancer Published Online: May 14, 2007.
Print Issue Date: June 15, 2007.
DOI: 10.1002/cncr. 22723

Click here for Abstract.

Click here for American Cancer Society Recommendations for Early Breast Cancer Detection (a detailed guide).

Written by: Catharine Paddock
Writer: Medical News Today