Long-term prognostic role of functional limitations among women with breast cancer.
BACKGROUND
The long-term prognostic role of functional limitations among women with breast cancer is poorly understood.


METHODS
We studied a cohort of 2202 women with breast cancer at two sites in the United States, who provided complete information on body functions involving endurance, strength, muscular range of motion, and small muscle dexterity following initial adjuvant treatment. Associations of baseline functional limitations with survival were evaluated in delayed entry Cox proportional hazards models, with adjustment for baseline sociodemographic factors, body mass index, smoking, physical activity, comorbidity, tumor characteristics, and treatment. Difference in covariates between women with and without limitations was assessed with Pearson χ(2) and Student t tests. All statistical tests were two-sided.


RESULTS
During the median follow-up of 9 years, 112 deaths were attributable to competing causes (5% of the cohort) and 157 were attributable to breast cancer causes (7% of the cohort). At least one functional limitation was present in 39% of study participants. Proportionately, more breast cancer patients with functional limitations after initial adjuvant treatment were older, less educated, and obese (P < .001). In multivariable models, functional limitations were associated with a statistically significantly increased risk of death from all causes (hazard ratio [HR] = 1.40, 95% confidence interval [CI] = 1.03 to 1.92) and from competing causes (HR = 2.60, 95% CI = 1.69 to 3.98) but not from breast cancer (HR = 0.90, 95% CI = 0.64 to 1.26). The relationship between functional limitations and overall survival differed by tumor stage (among women with stage I and stage III breast cancer, HR = 2.02, 95% CI = 1.23 to 3.32 and HR = 0.74, 95% CI = 0.42 to 1.30, respectively).


CONCLUSIONS
In this prospective cohort study, functional limitations following initial breast cancer treatment were associated with an important reduction in all-cause and competing-cause survival, irrespective of clinical, lifestyle, and sociodemographic factors.
Braithwaite
Dejana
D
Helen Diller Family Comprehensive Cancer Center and the Department of Epidemiology and Biostatistics, University of California, San Francisco, 185 Berry St, Ste 5700, San Francisco, CA 94107, USA. dbraithwaite@epi.ucsf.edu
Satariano
William A
WA
Sternfeld
Barbara
B
Hiatt
Robert A
RA
Ganz
Patricia A
PA
Kerlikowske
Karla
K
Moore
Dan H
DH
Slattery
Martha L
ML
Tammemagi
Martin
M
Castillo
Adrienne
A
Melisko
Michelle
M
Esserman
Laura
L
Weltzien
Erin K
EK
Caan
Bette J
BJ
D000203:Activities of Daily Living; D000328:Adult; D000367:Age Factors; D000368:Aged; D015992:Body Mass Index; D001943:Breast Neoplasms / Q000401:mortality* / Q000473:pathology / Q000503:physiopathology*; D015897:Comorbidity; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008019:Life Style; D008875:Middle Aged; D015999:Multivariate Analysis; D009367:Neoplasm Staging; D016017:Odds Ratio; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D011788:Quality of Life; D012307:Risk Factors; D012494:Sampling Studies; D013997:Time Factors; D014481:United States / Q000453:epidemiology