Validity of Adjuvant! Online program in older patients with breast cancer: a population-based study.
BACKGROUND
Adjuvant! Online is a prediction tool that can be used to aid clinical decision making in patients with breast cancer. It was developed in a patient population aged 69 years or younger, and subsequent validation studies included small numbers of older patients. Since older patients with breast cancer differ from younger patients in many aspects, the aim of this study was to investigate the validity of Adjuvant! Online in a large cohort of unselected older patients.


METHODS
We included patients from the population-based FOCUS cohort, which included all consecutive patients aged 65 years or older who were diagnosed with invasive or in-situ breast cancer between Jan 1, 1997, and Dec 31, 2004, in the southwestern part of the Netherlands. We included all patients who fulfilled the criteria as stated by Adjuvant! Online: patients with unilateral, unicentric, invasive adenocarcinoma; no evidence of metastatic or residual disease; no evidence of T4 features; and no evidence of inflammatory breast cancer. We entered data from all patients with the "average for age" comorbidity status (model 1) and with an individualised comorbidity status (model 2).


RESULTS
We included 2012 patients. Median age of patients in the cohort was 74·0 years (IQR 69·0-79·0). 904 (45%) of 2012 patients died during follow-up, whereas 326 (16%) patients had recurrence. Median follow-up for overall survival was 9·0 years (IQR 7·4-10·7), and 6·6 years (4·4-6·6) for patients without recurrence. Using model 1, Adjuvant! Online overestimated 10-year overall survival by 9·8% ([95% CI 5·9-13·7], p<0·0001) and 10-year cumulative recurrence survival by 8·7% ([6·7-10·7], p<0·0001). By contrast, when using model 2, Adjuvant! Online underestimated the 10-year overall survival by -17·1% ([95% CI -21·0 to -13·2], p<0·0001). However, when using model 2, Adjuvant! Online predicted cumulative recurrence accurately in all patients (-0·7% [95% CI -2·7-1·3], p=0·48).


CONCLUSIONS
Adjuvant! Online does not accurately predict overall survival and recurrence in older patients with early breast cancer.


BACKGROUND
Dutch Cancer Foundation.
Department of Surgery, Leiden University Medical Centre, Leiden, Netherlands; Department of Gerontology and Geriatrics, Leiden University Medical Centre, Leiden, Netherlands.
Nienke A
NA
de Glas
Department of Surgery, Leiden University Medical Centre, Leiden, Netherlands; Department of Gerontology and Geriatrics, Leiden University Medical Centre, Leiden, Netherlands.
Willemien
W
van de Water
Department of Medical Decision Making, Leiden University Medical Centre, Leiden, Netherlands.
Ellen G
EG
Engelhardt
Department of Surgery, Leiden University Medical Centre, Leiden, Netherlands; Department of Gerontology and Geriatrics, Leiden University Medical Centre, Leiden, Netherlands.
Esther
E
Bastiaannet
Department of Gerontology and Geriatrics, Leiden University Medical Centre, Leiden, Netherlands.
Anton J M
AJ
de Craen
Department of Medical Oncology, Leiden University Medical Centre, Leiden, Netherlands.
Judith R
JR
Kroep
Department of Medical Statistics, Leiden University Medical Centre, Leiden, Netherlands.
Hein
H
Putter
Department of Medical Decision Making, Leiden University Medical Centre, Leiden, Netherlands.
Anne M
AM
Stiggelbout
Department of Medical Oncology, Bronovo Hospital The Hague, The Hague, Netherlands.
Nir I
NI
Weijl
Department of Surgery, Leiden University Medical Centre, Leiden, Netherlands.
Cornelis J H
CJ
van de Velde
Department of Medical Oncology, Haga Hospital The Hague, Leyweg The Hague, Netherlands.
Johanneke E A
JE
Portielje
Department of Surgery, Leiden University Medical Centre, Leiden, Netherlands. Electronic address: g.j.liefers@lumc.nl.
Gerrit-Jan
GJ
Liefers
D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000401:mortality; D017024:Chemotherapy, Adjuvant; D015331:Cohort Studies; D005260:Female; D006801:Humans; D020407:Internet; D012372:ROC Curve