Accuracy of tests for predicting breast cancer recurrence vary significantly

Image courtesy Queen Mary
University of London

CANCER DIGEST – Feb. 17, 2018 – Tests used to predict breast cancer recurrence vary significantly in accuracy according to the first side-by-side comparison of the four most common tests.

In a study published in the Feb. 15, 2018 journal JAMA Oncology researchers led by Ivana Sestak, PhD of the Centre for Cancer Prevention at Queen Mary University of London, compared the predictive performance of the four most widely used biomarker analysis tests: Oncotype DX, PAM50, Breast Cancer Index (BCI) and the EndoPredict (EPclin), which all work by looking at the levels of multiple genes related to breast cancer.

“Being able to accurately predict the risk of breast cancer recurrence is even more important now that we are in an era where women are prescribed preventive endocrine (hormone) therapy for many years," said Sestak in a press release. "If we were better able to accurately assess a woman’s long-term risk, then some women may be able to end their endocrine therapy after five years. But for those deemed high risk of a late recurrence, continuing their endocrine therapy would be a valuable option.”

All of the tests have been endorsed by the major practice guidelines and European and US regulatory agencies but, until now, had never been compared for prognostic accuracy. 

The researchers compared the four tests’ ability to predict recurrence in a group of 774 postmenopausal women with the most common form of breast cancer, i.e. tumors that tested positive for estrogen receptors (ER+) and negative for the HER2 gene. They compiled the test results from the patients’ original tumor biopsies and then looked at recurrence among the women.

The team found that all four tests do provide substantial value for predicting recurrence of breast cancer up to 10 years after start of treatment in women whose tumors were negative for estrogen receptors (ER) and the HER2 gene.

For the critical time period of 5 to 10 years after treatment start, however, the results varied, since over 50 percent of women with estrogen receptor positive breast cancer recur within that time period. For those women the BCI, ROR and EPclin tests were more accurate in sorting which women had low-risk tumors from those with high-risk tumors.

For women whose tumors were ER+ and HER2+ only the ROR and EPclin tests, which include clinical information, such as tumor size, number of positive lymph nodes, etc. more accurately predicted recurrence.