A study finds that diagnostic mammography has improved cancer detection rates, but has also increased the abnormal interpretation rate.

This leads more women to undergo biopsies for tumour, or growth that is not cancerous, suggesting improvement in imaging. Mammography is the a technique using X-rays to diagnose and locate breast tumours. The findings, appeared online in the journal Radiology, revealed that the cancer detection rate rose from 25.3 per 1,000 in 2005 to 34.7 per 1,000. Along with improved cancer detection, some less desirable trends emerged. The abnormal interpretation rate, or the rate at which women are called back for biopsy, rose from 8.0 percent in 2005 to 12.6 percent in the new study.

With digital technology replacing film, the researchers decided it was time to revisit the old benchmarks, said study lead author Brian L. Sprague from the University of Vermont’s cancer center in Burlington. "Our goals in this study were to produce benchmarks that individual radiologists and breast imaging facilities can use to compare with their own practices and to convey trends in how the metrics have changed over the past 10 to 15 years," Dr. Sprague added.

This study included data from six registries comprising 418 radiologists and 92 radiology facilities. Mammography indication and assessments were collected on women undergoing diagnostic digital mammography and linked with cancer diagnoses from state cancer registries. The database included 401,548 examinations conducted from 2007 to 2013 on 265,360 women.

"While the improvements in cancer detection rates are encouraging, the increased abnormal interpretation rate is somewhat troubling in that we're trying to keep this rate down," Dr. Sprague said. The researchers suggested that improvements in imaging may do more to permit the visualisation of additional findings than helping in discriminating benign from malignant findings. "Overall, there is a lot of good performance out there, but there are definitely areas for improvement in positive predictive value and abnormal interpretation rate,” Dr. Sprague stated.