Screening mammography is likely to improve survival among women previously diagnosed with breast cancer, according to a clinical survey and cost-effectiveness analysis commissioned by the National Institute for Health Research in the U.K. and published in the September issue of Health Technology Assessment.
As breast cancer survival has improved, the question of optimal follow-up surveillance has emerged. Previous data have suggested that early detection of recurrent, second and new primary cancers provides a survival benefit, according to Clare Robertson, MD, of the health services research unit at University of Aberdeen in Aberdeen, Scotland. However, the optimal frequency of screening mammography and length of follow-up among this population remain unclear.
Robertson and colleagues designed a survey to assess follow-up protocols in the U.K., assess their effectiveness, estimate associated costs and cost effectiveness of various surveillance and follow-up protocols and identify future research needs.
The researchers surveyed breast surgeons and radiologists in the U.K. to assess surveillance regimens and examine feasible alternatives. They also completed an economic model to determine cost effectiveness.
The 183 surgeons and radiologists who responded to the survey indicated a variety of surveillance strategies, with most initiating mammography 12 months after breast-conserving surgery or mastectomy. The most common screening interval was annual mammography, followed by biennial mammography. Seventy-two percent of respondents discharged women from surveillance mammography 10 years after surgery.
However, though there are some common patterns in surveillance mammography practice, the researchers wrote that their findings suggest that there is "considerable variation in the combinations of start, frequency, duration and discharge from surveillance mammography.”
Systemic literature reviews for clinical effectiveness suggested that surveillance mammography provides a survival benefit compared with regimens that do not include mammography. Data regarding test performance showed the highest sensitivity for MRI and the highest specificity for mammography, with studies reporting varying sensitivity and specificity for all screening studies: MRI, mammography and ultrasound.
The economic evaluation indicated that surveillance mammography at a one-year interval provided the highest net benefit and was most likely to be considered cost-effective at a societal willingness to pay for a quality-adjusted life-year (QALY) of either EUR 20,000 ($31,000) or EUR 30,000 ($46,000). Robertson et al noted that screening MRI can provide incremental costs less than EUR 30,000 ($46,000) depending on the surveillance interval and incidence.
The researchers suggested that women at higher risk for ipsilateral breast tumor recurrence or metachronous contralateral breast cancer could benefit from more intensive follow-up, while those with less likelihood of disease could be screened less often. However, they acknowledged the challenges of a staggered approach, which includes unnecessary patient anxiety.
Robertson and colleagues identified several directions for future research, including improved collection of details regarding mode of detection for recurrent cancers, direct head-to-head comparison of screening modalities in this population, economic modeling and a definitive randomized controlled trial that examines mammography and MRI.
For more about screening mammography in practice, please read USPSTF Guidelines Two Years Later: The Fallout Continues.