Rate of progression in breast cancer and the disease-free interval

Patients with breast cancer have been classified as having slow, intermediate, or rapid rates of disease progression through the use of a clinical index, which depends on data from the patient's history. Patients without evidence of adverse progression of disease who waited 4 months or more between their first symptom and treatment were classified as slow; those waiting less than 4 months, intermediate. Patients with evidence of adverse progression were classified as rapid. We evaluated the 616 patients who had no evidence of distant disease at the time of treatment from an inception cohort of 685 patients to assess the correlation between the slow, intermediate, and rapid strata and the disease-free interval. Ten percent were in TNM stage I, 63% in TNM stage II, and 26% in TNM stage III. Among the 43% (266/616) of patients who developed recurrent disease, the median disease-free interval was longest in the slow stratum (33.6 months) and shortest in the rapid stratum (19.5 months). The difference in the 10-year disease-free survival rates in the three strata was significant (chi 2 = 26.4; p less than 0.001). The findings were similar when prognosis was assessed within the TNM stage or nodal groups. For example, in the rapid stratum, node-negative and node-positive patients had almost identical disease-free intervals. The independence of the contribution of the rate of disease progression strata to predicting disease-free survival was confirmed through the Cox analysis. If breast cancer did recur, the manifestation occurred sooner in patients who were demarcated as rapid by the clinical index. Thus the index estimates the aggressiveness of residual disease when it is present.