Population-based validation of the prognostic model ADJUVANT! for early breast cancer.
OBJECTIVE
Adjuvant! (www.adjuvantonline.com) is a web-based tool that predicts 10-year breast cancer outcomes with and without adjuvant systemic therapy, but it has not been independently validated.


METHODS
Using the British Columbia Breast Cancer Outcomes Unit (BCOU) database, demographic, pathologic, staging, and treatment data on 4,083 women diagnosed between 1989 and 1993 in British Columbia with T1-2, N0-1, M0 breast cancer were abstracted and entered into Adjuvant! to calculate predicted 10-year overall survival (OS), breast cancer-specific survival (BCSS), and event-free survival (EFS) for each patient. Individual BCOU observed outcomes at 10 years were independently determined. Predicted and observed outcomes were compared.


RESULTS
Across all 4,083 patients, 10-year predicted and observed outcomes were within 1% for OS, BCSS, and EFS (all P > .05). Predicted and observed outcomes were within 2% for most demographic, pathologic, and treatment-defined subgroups. Adjuvant! overestimated OS, BCSS, and EFS in women younger than age 35 years (predicted-observed = 8.6%, 9.6%, and 13.6%, respectively; all P < .001) or with lymphatic or vascular invasion (LVI; predicted-observed = 3.6%, 3.8%, and 4.2%, respectively; all P < .05); these two prognostic factors were not automatically incorporated within the Adjuvant! algorithm. After adjusting for the distribution of LVI, using the prognostic factor impact calculator in Adjuvant!, 10-year predicted and observed outcomes were no longer significantly different.


CONCLUSIONS
Adjuvant! performed reliably. Patients younger than age 35 or with known additional adverse prognostic factors such as LVI require adjustment of risks to derive reliable predictions of prognosis without adjuvant systemic therapy and the absolute benefits of adjuvant systemic therapy.
Olivotto
Ivo A
IA
Breast Cancer Outcomes Unit, Vancouver Island Centre, 2410 Lee Avenue, Victoria, BC V8R 6V5, Canada. iolivott@bccancer.bc.ca
Bajdik
Chris D
CD
Ravdin
Peter M
PM
Speers
Caroline H
CH
Coldman
Andrew J
AJ
Norris
Brian D
BD
Davis
Greg J
GJ
Chia
Stephen K
SK
Gelmon
Karen A
KA
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000473:pathology*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D020407:Internet; D008875:Middle Aged; D008962:Models, Theoretical; D011379:Prognosis; D012984:Software