Health Minister Shona Robison's recent encouragement for women to attend for breast screening is to be welcomed.

It is puzzling why the numbers attending are falling. Mammograms can detect early invasive breast tumours before they become large enough to be apparent on physical examination, meaning they may be treated more conservatively, also giving the woman a generally better longer-term outlook than for more advanced cancers.

Would it be helpful for the NHS to be more specific about the "risks" cited for mammography? There is a potential cancer risk, around 0.01%, from the small amount of radiation from mammograms. Women need to weigh that up against the 1 in 12 lifetime risk of breast cancer.

Mammograms cannot pick up every cancer, but that is a limitation, not a risk. Mammograms also pick up smaller numbers of early non-invasive cancers which may never become life-threatening and may be "over-treated", but should that be termed a "risk"? Whether to treat or not may be a difficult decision for the woman. She needs to weigh up how she feels about knowing she may develop an invasive cancer.

It has also been argued that since most breast cancers are self-detected, much money and anxiety is questionably spent on population screening. My invasive tumour had grown to 55mm before I noticed it, six months before my routine mammogram was due. Most mammogram-detected tumours are invasive, most of them would have been unlikely to be detected on physical examination alone. Far from being of questionable value, should breast screening be extended to more frequently than the current three-year interval?

Anne Martin

Clackmannan