Luisa Dillner writes that "while screening may catch [breast cancer] early, there's no guarantee" (Dr Dillner's health dilemmas: should I be screened for breast cancer?, G2, 1 August). Breakthrough Breast Cancer hopes this will not discourage women from attending their breast-screening appointments. One in eight women will develop breast cancer and screening aims to detect the disease at the earliest possible stages.

The current debate over screening may be very confusing. As Dr Dillner highlights, "a paper in this week's BMJ says that screening hasn't improved mortality rates". But another study published in Radiology in June concludes that breast screening results in a 30% reduction in breast cancer mortality among women invited. This is consistent with the findings of many other large screening trials.

The number of deaths from breast cancer is falling due to earlier diagnosis and better treatment by specialist teams, but the exact number of lives saved will continue to be debated. Dr Dillner herself quoted two separate figures, which shows that lives are saved, regardless of whether it is 1,347 or 500 a year.

So, how are women expected to make sense of this complicated issue? A particularly important aspect of breast screening, largely ignored in the current debate, is that it can detect breast cancer at the earliest possible stages when no other symptoms are obvious – and the earlier breast cancer is diagnosed, the better, as treatment options are more likely to be less aggressive and have successful outcomes. For many women, this is enough of a reason to attend breast screening.

However, Dr Dillner is right to highlight that "not all diseases progress". Breast screening can detect a non-invasive form of breast cancer called ductal carcinoma in situ (DCIS). What Dr Dillner doesn't highlight is that it is, unfortunately, very difficult to predict which of these cancers will develop into life-threatening disease and which will not – so treatment will be offered. Many women welcome this intervention.

Dr Dillner asks the very important question "so how can you decide if screening is for you?" and also highlights a letter in the Sunday Times "where some of the greats in cancer research argue that if women knew what the clinical evidence was they might turn down the offer of screening". The choice to attend breast screening can only be made by the individual, and women are encouraged to read the information leaflet that accompanies all invitations for screening. It is extremely important that women are given clear, balanced and good-quality information about the benefits and risks of screening to enable them to make informed decisions.

The latest paper published in the BMJ does not tip the balance in favour of abolishing breast screening. It is important that the evidence for and against screening is continually reviewed and consideration given to how breast screening can be best targeted. However, for now, let's focus on ensuring we have the best possible screening service and that women are provided with the information they need, so we can continue to detect this disease earlier and treat it effectively.