Improvement in the prognosis of breast cancer from 1965 to 1984

The prognosis of breast cancer has improved over the past three decades. It is uncertain, however, whether this improvement results from an increase in the cure rate, extension of the life span of uncured patients, or some combination.

From the Connecticut Tumor Registry, we obtained data on 25,091 patients with localized (node-negative) and regionally metastatic (node-positive) breast cancer who were diagnosed over the two decades between 1965 and 1984, with follow-up through 1993. The data for these patients were analyzed using a variety of parametric models to quantitate likelihood of cure and median survival time among uncured patients. These models incorporate the assumption that time to death from breast cancer follows a specific distribution.

For patients with node-negative disease, parametric analysis revealed no significant difference in cured-fraction or median survival time over the two decades studied. For patients with node-positive disease, however, a significant increase in median survival time (P < .001) was found during the second decade (1970 to 1979). There was also a trend toward a higher cured-fraction over time, but this was not statistically significant.

This study confirms that patients with node-positive disease had an improved prognosis over the two decades studied. Parametric analysis suggests that this improvement reflects primarily an increase in the median survival time for uncured patients, although there is a trend toward an increase in the likelihood of cure.