BACKGROUND.
Stage and histologic type have a significant impact on the long term clinical course of breast carcinoma. Clinical course is governed by two components: likelihood of cure and median tumor-related survival time among uncured patients. Estimates of these components can be derived only by using survival models that incorporate cured fraction as a specific parameter.
METHODS.
The prognostic value of stage and histologic type was determined for 163,808 patients with breast carcinoma using the log normal and log logit curebased survival models. Follow-up ranged from 1 month to 19 years and was obtained from the SEER Program.
RESULTS.
In approximate terms, ductal carcinoma was diagnosed in 70% of the patients, with estimated cured fractions of 2/3 and 113 for local, and regional disease, respectively. Estimates of median survival times for uncured patients were 10 and 5 years. Findings were similar for patients with tumors of miscellaneous histologic types. For patients with medullary carcinoma, cured fractions were relatively high at 82% and 64%, but median survival times were relatively short at 4 and 3 years. Corresponding values for patients with invasive comedo carcinoma were 82% and SO%, with median survival times of 6 and 4 years. For patients with mucinous, lobular, and ductolobular carcinomas, parametric analysis gave inconsistent estimates of cured fraction, but findings suggested unusually long tumor-related survival times.
CONCLUSIONS.
Cure-based parametric survival models offer valuable insight into the impact of stage and histology on the clinical course of breast cancer. Cancer