ER-Positive, Negative Breast Cancers Have Different Long-Term Recurrence Risks

Breast cancer survivors with estrogen receptor (ER)-positive disease had a lower annual risk of recurrence within the first 5 years after diagnosis, though these patients then had higher rates than ER-negative patients after 5 years, according to a new study. The ER-positive patients maintained significant recurrence rates through extended follow-up out to 25 years.

Previously, little was known about patterns of recurrence after 10 or more years of follow-up in breast cancer patients. “A better description of relapse patterns, resulting in a better understanding of time-specific risk, could lead to targeted therapeutic approaches and enhanced surveillance methods, ultimately leading to improved patient outcomes,” wrote study authors led by Marco Colleoni, MD, of the European Institute of Oncology in Milan, Italy.

The new study included data on 4,105 patients diagnosed between 1978 and 1985 and included in the International Breast Cancer Study Group clinical trials I to V. The results were published online ahead of print in the Journal of Clinical Oncology.

The full cohort had a median follow-up of 24.2 years, during which time 2,590 patients (63.1%) had died and 2,451 (59.7%) had a breast cancer recurrence. The annualized recurrence hazard for the entire cohort was 10.4% during the first 5 years; this peaked between years 1 and 2, at 15.2%. From years 5 to 10, the recurrence rate was 4.5%; it was 2.2% from years 10 to 15, 1.5% from years 15 to 20, and 0.7% from years 20 to 25.

In the first 5 years, patients with ER-positive disease had a 9.9% risk of recurrence, compared with 11.5% for ER-negative patients (P = .01). This had flipped by the second 5-year period (the hazards crossed between years 2 and 3), at 5.4% for ER-positive and 3.3% for ER-negative patients. ER-negative patients saw that decline to 1.3% in years 10 to 15, 1.2% in years 15 to 20, and 1.4% in years 20 to 25. For ER-positive patients, the rates were 2.9% in years 10 to 15, 2.8% in years 15 to 20, and 1.3% in years 20 to 25.

During the first 5-year period, ER-negative patients had more distant recurrences than ER-positive patients, though after 5 years the cumulative incidence of distant recurrence increased faster in the ER-positive patients.

The obvious limitation of this trial is that the medications offered during the periods of diagnosis studied here are largely different from what is offered today, and thus extrapolation of these results may be difficult.

Still, the differentiation between ER-positive and negative patients offers an opportunity, the authors wrote. “New targeted treatments and different modes of breast cancer surveillance for preventing late recurrences within this population should be studied,” they concluded.