The Study: We told you the E5103 trial was not for naught. One of the interesting secondary analyses is the EL112 substudy. As a reminder, E5103 enrolled ~5K women with HER2(-) breast cancer at “high risk” of recurrence. Those who remained without evidence of disease 4.5-7.5 years out from enrollment in E5103 were eligible for EL112. 547 women participated in EL112 by having blood drawn for CTC analysis, again at least 4.5 years out from treatment, at which time 26 women were found to have CTCs present. Everyone was observed, and, at a median follow-up from CTC analysis of 2.5 years, 24 of 547 women had clinical recurrences. Only two failures were locoregionally isolated and only one was ER(-)—both supporting known epidemiologic trends of late ER(+) distant failures. And now for the novel finding: The recurrence rates per person-year of follow-up were 21% among those with CTCs and 2% among those without, yielding a hazard ratio of over 13.
Bottom Line: The presence of CTCs in women with no evidence of disease several years out from treatment for ER(+) breast cancer appears predictive of subsequent clinical failure. TBD: cost effectiveness. | Sparano, JAMA Oncol 2018