First national data on breast cancers that occur between screenings
16 February 2011 - The ICR has conducted the first UK-wide study into the rate of breast cancers diagnosed between scheduled screenings.
Interval cancers can include cancers that develop and become symptomatic in the time between screening appointments, as well as those missed or undetectable by mammography that are subsequently detected symptomatically.
The study led by Dr Sue Moss examined data from more than 7.3 million women aged 50 to 64 who had a routine screen between April 1997 and March 2003 at one of 92 screening centres in England, Wales and Northern Ireland.
The analysis found 2.91 per 1,000 women who had a negative screen were diagnosed with breast cancer before their next screen was due. Over the six year period of the study, around 44,000 cancers were detected through routine screening and around 21,000 interval cancers were diagnosed. Interval cancers therefore accounted for almost one third of all diagnosed breast cancers over this period.
“The rate at which women developed breast cancer between screenings was higher than expected, and is likely to reflect the fact that breast cancer rates are rising in general,” says Dr Moss. “Reducing the length of time between screenings would result in a lower proportion of interval cancers, but not necessarily a significant reduction in mortality.”
The UK NHS Breast Screening Programme invites all women aged between 50 and 70 for a mammogram every three years, equating to around 1.5 million eligible women a year.
