Predictors of time to death after distant recurrence in breast cancer patients.

Abstract

After experiencing a distant recurrence, breast cancer patients have a poor prognosis; fewer than 5% survive for ten or more years. However, the time to death is highly variable, ranging from a few months to many years. The purpose of this study is to identify, in a large hospital-based series of patients with early-stage breast cancer, factors which predict survival after distant recurrence. We studied a cohort of 2312 women diagnosed with invasive breast cancer at Women's College Hospital between 1987 and 2000 (stages I-III). For each patient, we abstracted information on age at diagnosis, the initial presentation of the cancer (tumour size, lymph node status, tumour grade, ER status, PR status, HER2 status), treatment (surgery, radiotherapy, chemotherapy, hormone therapy), the dates of all tumour recurrences (local, regional, distant) and the dates and causes of death. The Cox proportional hazards model was used to estimate the univariate and multivariate hazard ratios for death from breast cancer following distant recurrence associated with the various tumour features. After a mean follow-up of 12.8years from diagnosis, 523 distant recurrences were recorded among women in the cohort (23% of 2312) and 604 women (26%) died of breast cancer. For the 484 women who had a distant recurrence on record and died of breast cancer, the mean time from distant recurrence to death was 2.0years (range 0-11.9years). In a multivariate analysis, only two factors were significantly associated with time to death after distant recurrence: ER status (positive vs. negative, HR 0.56; 95% CI 0.43-0.71; p < 0.0001) and tumour grade (high vs. low, HR 1.87; 95% CI 1.16-3.01; p = 0.01). Among ER-negative patients (N = 175), high tumour grade and a short time from diagnosis to distant recurrence were associated with a rapid time to death. Among ER-positive patients (N = 336), there was no significant independent predictor of time from recurrence to death. Among ER-negative breast cancer patients, the time to death after distant recurrence was predictable to some extent; women with a short time from diagnosis to recurrence and/or with high-grade tumours were more likely to succumb to breast cancer within 3years. Among ER-positive breast cancer patients who experience a distant recurrence, the time to death varies substantially and between patients could not be predicted by tumour factors or treatment. This suggests that for ER-positive patients, the factors that determine the time from diagnosis to distant recurrence do not predict the course of the cancer post-recurrence.