Reason for late-stage breast cancer: absence of screening or detection, or breakdown in follow-up?
BACKGROUND
Mammography screening increases the detection of early-stage breast cancers. Therefore, implementing screening should reduce the percentage of women who are diagnosed with late-stage disease. However, despite high national mammography screening rates, late-stage breast cancers still occur, possibly because of failures in screening implementation.


METHODS
Using data from seven health care plans that included 1.5 million women aged 50 years or older, we conducted retrospective reviews of chart and automated data for 3 years before 1995-1999 diagnoses of late-stage (metastatic and/or tumor size > or =3 cm; case subjects, n = 1347) and early-stage breast cancers (control subjects, n = 1347). We categorized the earliest screening mammogram during the period 13-36 months before diagnosis as none (absence of screening), negative (absence of detection), or positive (potential breakdown in follow-up). We compared the proportion of case and control subjects in each category of screening implementation and estimated the likelihood (odds ratio [OR] with 95% confidence intervals [CIs]) of late-stage breast cancer. We also evaluated demographic characteristics associated with absence of screening in women with late-stage disease. All statistical tests were two-sided.


RESULTS
Absence of screening, absence of detection, and potential breakdown in follow-up were distributed differently among case (52.1%, 39.5%, and 8.4%, respectively) and control subjects (34.4%, 56.9%, and 8.8%, respectively) (P = .03). Among all women, the odds of having late-stage cancer were higher among women with an absence of screening (OR = 2.17, 95% CI = 1.84 to 2.56; P<.001). Among case patients, women were more likely to be in the absence-of-screening group if they were aged 75 years or older (OR = 2.77, 95% CI = 2.10 to 3.65), unmarried (OR = 1.78, 95% CI = 1.41 to 2.24), or without a family history of breast cancer (OR = 1.84, 95% CI = 1.45 to 2.34). A higher proportion of women from census blocks with less education (58.5% versus 49.4%; P = .003) or lower median annual income (54.4% versus 42.9%; P = .004) were in the absence-of-screening category compared with the proportion for the other two categories combined.


CONCLUSIONS
To reduce late-stage breast cancer occurrence, reaching unscreened women, including elderly, unmarried, low-income, and less educated women, should be made a top priority for screening implementation.
Taplin
Stephen H
SH
Group Health Cooperative, Seattle, WA, USA. taplins@mail.nih.gov
Ichikawa
Laura
L
Yood
Marianne Ulcickas
MU
Manos
M Michele
MM
Geiger
Ann M
AM
Weinmann
Sheila
S
Gilbert
Joyce
J
Mouchawar
Judy
J
Leyden
Wendy A
WA
Altaras
Robin
R
Beverly
Robert K
RK
Casso
Deborah
D
Westbrook
Emily Oakes
EO
Bischoff
Kimberly
K
Zapka
Jane G
JG
Barlow
William E
WE
D000367:Age Factors; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000453:epidemiology* / Q000473:pathology / Q000628:therapy; D016022:Case-Control Studies; D016001:Confidence Intervals; D042241:Early Diagnosis; D004522:Educational Status; D005260:Female; D006801:Humans; D008327:Mammography / Q000706:statistics & numerical data*; D017533:Marital Status; D008403:Mass Screening / Q000379:methods* / Q000706:statistics & numerical data; D008499:Medical Records; D009367:Neoplasm Staging; D016017:Odds Ratio; D012189:Retrospective Studies; D012307:Risk Factors; D014481:United States / Q000453:epidemiology