The article that I posted above addresses the difference in the pattern of recurrence for triple negative compared to ER+ breast cancer.

"Many triple-negative breast cancers differ significantly from hormone-positive tumors in that they are less likely to recur late, that is, five or more years following diagnosis.

With estrogen-receptor-positive tumors, the incidence of recurrence remains steady for at least 20 years following the diagnosis, even for very small, early-stage tumors. In fact, people who have estrogen-receptor-positive early-stage breast cancer are more likely to have a recurrence after five years than in the first five years following diagnosis.

In women with hormone-positive tumors who are treated with hormonal therapy for five years after surgery and/or radiation/chemotherapy, the distant recurrence rate between year five and year 20 ranges from 14% for small, node-negative tumors (T1N0) to 47% for larger tumors that have spread to lymph nodes (T2N4-9).8

The lower incidence of late recurrence with triple-negative breast cancer wasn’t as clear until recently, as many studies only went out five years when looking at recurrence and survival.

A 2018 study, however, looked at people with triple-negative breast cancer who were disease-free five years after their diagnosis. Among this group, the 10-year recurrence-free rate was 97% and the 15-year recurrence-free rate was 95%."