Only nodal status and tumor size provided statistically significant prognostic information for predicting recurrences 5 to 10 years after diagnosis for postmenopausal women with early estrogen receptor–positive breast cancer enrolled in the monotherapy arms of the ATAC (Arimidex, Tamoxifen, Alone or in Combination) trial.
“Nodal status and tumor size were at least as strong in years 5 to 10 as in years 0 to 5,” Ivana Sestak, PhD, Queen Mary University, London, and coauthors reported in the Journal of the National Cancer Institute. None of the other immunohistochemical (IHC4) markers provided significant prognostic information in years 5 to 10. “These results may help select patients who could benefit most from hormonal therapy beyond 5 years of treatment,” the authors concluded.
The investigators analyzed data from 940 postmenopausal women for whom values for IHC4, and two gene-expression tests—the recurrence score and the PAM50 risk of recurrence—were available. These women received either tamoxifen or anastrozole alone and did not receive chemotherapy. “There were 154 distant recurrences; 71 occurred in years 0 to 5 and 83 occurred in years 5 to 10 (for all recurrence: 83 in years 0 to 5, 107 in years 5 to 10),” the investigators summarized.
“Nodal status and tumor size were the only individual factors that added prognostic information in years 5 to 10 in the multivariable model (nodal status: χ2 = 21.72, P <.001; tumor size: χ2=10.52, P = .001; ),” the investigators reported. “None of the individual immunohistochemical markers added prognostic information in this time period.” The risk of recurrence score “was the strongest molecular prognostic factor in the late follow-up period (χ2 = 16.29; P < .001).” Results were similar for all subgroups and all recurrences.
Major Clinical Problem
“The prediction and treatment of late breast cancer recurrence is an important and largely unmet need and remains a major clinical problem,” the authors concluded. “Although nodal status and tumor size added prognostic value 5 years after diagnosis, conventional immunohistochemical markers did not add information for late recurrence of those evaluated. The [risk of recurrence] score was the only molecular factor that showed promise in predicting late recurrence and to discriminate patients into low and high risk for late distant recurrence,” they said.
“These results help to identify women who are at high risk of late recurrence and who may benefit from either more intensive treatment (ie, chemotherapy) or extended endocrine treatment beyond 5 years. Validation of these results in other cohorts is needed,” the authors added. ■