Reading the prognosis of the individual with breast cancer.
OBJECTIVE
To obtain better survival estimates for the individual than is provided by placement in an NPI group.


METHODS
Consecutive primary operable breast cancers treated at Nottingham City Hospital 1990-1999. Ten year % actuarial survivals plotted for 10 ranges of NPI from 2.0 to 6.9. There is an excellent inverse correlation between median NPI value for each range and survival at 10 years. To enable estimation of survival for all individual values of NPI, a curve fitting technique applied to these results (by G.B.) gave the formula to estimate survival from the individual's NPI score: 10 year % survival for the individual=-3.0079 x NPI(2)+12.30 x NPI+83.84. This gave an r(2) of 0.98.


CONCLUSIONS
Greater accuracy in individual survival prediction is obtained by dividing women into 10 groups by NPI scores than in the originally described six groups; rank order of survival in relation to NPI score is preserved. A curve fitting technique has been applied to these data to give a formula for the prediction of 10 year survival for every 0.1 value of NPI.
Blamey
R W
RW
The Breast Institute, Nottingham City Hospital, Nottingham NG5 1PB, UK. wendy.bartlam@nuh.nhs.uk
Pinder
S E
SE
Ball
G R
GR
Ellis
I O
IO
Elston
C W
CW
Mitchell
M J
MJ
Haybittle
J L
JL
D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000401:mortality*; D005260:Female; D006801:Humans; D008875:Middle Aged; D011379:Prognosis; D012044:Regression Analysis; D012307:Risk Factors; D016019:Survival Analysis; D015996:Survival Rate