European Journal of Cancer: Highlights of Issue 39:12

Focus on breast cancer and screening

Several studies on screening in breast cancer are included in this issue. A few of these are highlighted below.

Effects of screening on incidence and mortality

Botha and colleagues studied the mortality and incidence trends in 16 European countries in women aged 35-74 years. Data were obtained from the EUROpean Cancer Incidence and Mortality (EUROCIM) database. 6 of the countries had screening programmes in place. Incidence increased in all of the countries examined. Some screening-related increases were observed. The trends in mortality changed over the time period examined with previously increasing trends decreasing or flattening out in many of the countries. The declines in mortality occurred in the screened countries and screened age groups, but also in those that were not screened. This suggests other factors, in addition to screening, - such as improvements in therapy - are also responsible for the observed trends.

Screening attendance is not adversely affected by previous false-positive mammographic results

This is the conclusion of a questionnaire-based study by Lampic and colleagues who examined the subsequent screening attendance record in 517 women with previous false-positive results over the 2 years following their screening participation. They compared their results with 285 controls with previously normal findings on mammography and found a 95% attendance record for the subjects and 94% record for the controls. This was despite the fact that anxiety levels of the subjects in connection with their next scheduled screening were higher compared with controls. Furthermore, at the one year assessment, the subjects also reported a significantly higher frequency of breast self-examination (BSE) than the controls and the authors suggest that a false-positive mammogram may have "a positive impact on BSE".

Overdiagnosis of non-progressive DCIS is small

In this issue, Yen and colleagues examined the rate of overdiagnosis of non-progressive ductal carcinoma in situ (DCIS) in breast cancer screening programmes and found such levels were small. Using a modelling system, they examined data from studies in the UK, Sweden, Netherlands, Australia and the USA and found 37% of DCIS cases at the prevalence screen were estimated to be non-progressive. In contrast, only 4% of such cases were found at the incidence screen. Moreover, women attending a prevalence screen had a 19 times higher chance of being diagnosed with progressive DCIS or an invasive tumour. They concluded that although "there is an element of overdiagnosis of DCIS in breast cancer screening, the phenomenon is small in both relative and absolute terms".

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