Probabilities of death from breast cancer and other causes among female breast cancer patients.

BACKGROUND: Among cancer patients, probabilities of death from that cancer and other causes in the presence of competing risks are optimal measures of prognosis and of mortality across demographic groups. We used data on breast cancer patients from the Surveillance, Epidemiology, and End Results (SEER) Program in a competing-risk analysis.
METHODS: We determined vital status and cause of death for 395,251 white and 35,259 black female patients with breast cancer diagnosed from January 1, 1973, through December 31, 2000, by use of SEER data. We calculated probabilities of death from breast cancer and other causes according to stage, race, and age at diagnosis; for cases diagnosed from January 1, 1990, to December 31, 2000, we also calculated some such probabilities according to tumor size and estrogen receptor (ER) status. All statistical tests were two-sided.
RESULTS: The probability of death from breast cancer after nearly 28 years of follow-up ranged from 0.03 to 0.10 for patients with in situ disease to 0.70 to 0.85 for patients with distant disease, depending on race and age. The probability of death from breast cancer at the end of the follow-up period generally declined with age at diagnosis; the probability among the oldest (> or =70 years) compared with the youngest (<50 years) patients was 33% lower for white and 46% lower for black patients with localized disease and 14% lower for white patients and 13% lower for black patients with distant disease. The probability of death from breast cancer exceeded that from all other causes for patients diagnosed with localized disease before age 50 years, with regional disease before age 60 years, and with distant disease at any age. The probability of death from breast cancer for patients diagnosed with localized or regional disease was statistically significantly greater in black patients than in white patients (all six P values < or =.01 for age groups 30-49 to 60-69 years; two P values < or =.04 for ages > or =70 years). Among patients with localized or regional disease and known ER status, the probability of death from breast cancer after nearly 11 years of follow-up ranged from 0.04 to 0.11 for patients with localized ER-positive tumors of 2 cm or less to 0.37 to 0.53 for patients with regional ER-negative tumors.
CONCLUSIONS: The probability of death from breast cancer versus other causes varied substantially according to stage, tumor size, ER status, and age at diagnosis in both white and black patients.