Temporal trends in breast cancer surgery in Ontario: can one randomized trial make a difference?
OBJECTIVE
To assess the effect of a single randomized clinical trial, the National Surgical Adjuvant Breast Project (NSABP) B-06, on the surgical management of breast cancer in women.


METHODS
Retrospective cohort study.


METHODS
All hospitals in Ontario.


METHODS
A consecutive sample of 37,447 women with breast cancer newly diagnosed from Jan. 1, 1980, to Dec. 31, 1989, linked to a surgical procedure record in the Ontario Cancer Registry.


METHODS
The most invasive surgical procedure used within 90 days of diagnosis.


RESULTS
Unilateral breast-ablative surgery (BAS) was performed in 57.3% of the women and breast-conserving surgery (BCS) in 31.6%. The annual rate of BAS declined from 77.5% in 1980 to 44.2% in 1989 and the rate of BCS rose from 12.5% in 1980 to 43.5% in 1989. The decline was linear from 1980 to 1984 and then accelerated significantly in 1985 (p < 0.0001), after the results of the NSABP B-06 trial were published.


CONCLUSIONS
One randomized clinical trial can have an immediate and profound effect on medical practice.
Iscoe
N A
NA
Toronto Bayview Regional Cancer Centre, Ontario Cancer Treatment and Research Foundation.
Naylor
C D
CD
Williams
J I
JI
DeBoer
G
G
Morgan
M W
MW
Fehringer
G
G
Holowaty
E
E
D017677:Age Distribution; D000368:Aged; D001943:Breast Neoplasms / Q000453:epidemiology / Q000601:surgery*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D008408:Mastectomy / Q000706:statistics & numerical data / Q000639:trends*; D015412:Mastectomy, Segmental / Q000639:trends; D008875:Middle Aged; D009864:Ontario / Q000453:epidemiology; D010818:Practice Patterns, Physicians'; D016032:Randomized Controlled Trials as Topic; D012189:Retrospective Studies; D014481:United States