A study published online May 3rd in the Journal of the National Cancer Institute says that breast cancers that are first detectable in the interval between screening mammograms are more likely to be aggressive, fast-growing tumors.
Other studies have shown that cancers diagnosed between mammograms, known as interval cancers, tend to have a worse prognosis than those detected during routine screening. This study examined the difference between "true" interval cancers—those not detectable on the previous mammogram—and "missed" interval cancers—those not detected on the previous mammogram due to technical errors or misinterpretation.
The authors, Anna M. Chiarelli, Ph.D., of Cancer Care Ontario, and colleagues, analyzed data from the Ontario Breast Screening Program for 288 women with true interval cancers and 87 women with missed interval cancers. Both kinds of interval tumors were compared to screen-detected tumors in 450 women who were similar in terms of age, location of the screening center, and length of time since their last mammogram. Their research was supported by a grant from the Canadian Breast Cancer Research Alliance.
The authors conclude that the findings suggest "a need for further advancement in imaging technologies to detect certain types of breast carcinomas and different approaches for early detection of fast-growing tumors."