The effects of mammographic detection and comorbidity on the survival of older women with breast cancer.
OBJECTIVE
To determine an upper age limit or quantifiable level of comorbidity that would render mammography screening ineffectual in decreasing mortality in women aged 65 and older.


METHODS
Retrospective cohort study.


METHODS
Upper midwestern United States.


METHODS
Five thousand one hundred eighty-six predominantly Caucasian women aged 65 to 101 diagnosed with invasive breast cancer from 1986 through 1994. Data were obtained from The Upper Midwest Tumor Registry System, a regional consortium database in Minnesota, North Dakota, and South Dakota.


METHODS
Relative risks (RRs) of death were computed for patients with mammographically detected tumors, stratified by age and comorbidity. Survival analysis was performed, stratified by level of comorbidity and method of tumor detection.


RESULTS
Patients with mammographically detected tumors and no comorbidity experienced significantly lower RRs of death in every age group (range P <.001 to P =.039). Women with mammographically detected tumors and mild to moderate comorbidity had RRs of death as follows: age 65 to 69 (RR = 0.32, 95% confidence interval (CI) = 0.15-0.69), age 70 to 74, (RR = 0.45, 95% CI = 0.22-0.91); age 75 to 79 (RR = 0.47, 95% CI = 0.25-0.88), age 80 and older (RR = 0.52, 95% CI = 0.33-0.80). Women with severe or multiple comorbidities experienced no improvement in survival with mammographically detected tumors.


CONCLUSIONS
Mammographic detection of breast cancer may be associated with a significantly decreased risk of death for older women of all ages, even for women with mild to moderate levels of comorbidity, but for older women with severe or multiple comorbidities, mammography is not associated with improvement in overall survival.
McPherson
Carol P
CP
Oncology Research Program, Park Nicollet Institute, 3800 Park Nicollet Boulevard, 2-South, Minneapolis, MN 55416, USA. mcphec@parknicollet .com
Swenson
Karen K
KK
Lee
Martin W
MW
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000175:diagnosis / Q000401:mortality*; D015331:Cohort Studies; D015897:Comorbidity; D005260:Female; D006801:Humans; D008327:Mammography / Q000706:statistics & numerical data*; D008403:Mass Screening / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D012306:Risk; D016019:Survival Analysis; D014481:United States / Q000453:epidemiology