Journal of Clinical Oncology, 2004 ASCO Annual Meeting Proceedings (Post-Meeting Edition).
Vol 22, No 14S (July 15 Supplement), 2004: 522
© 2004 American Society of Clinical Oncology

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Abstract

An independent population-based validation of the adjuvant decision-aid for stage I-II breast cancer

BC Cancer Agency, Victoria, Vancouver and Surrey, BC, Canada; University of Texas, San Antonio, TX

522

Background: ADJUVANT! (ADJ! [JCO 2001;19:980–91]) is a computer model which predicts 10-yr overall (OS), breast cancer-specific (BCSS) and event-free (EFS) survival with and without systemic therapy using recognised prognostic factors. Oncologists use it to provide information to patients about prognosis and treatment choice. ADJ! has not been independently validated despite widespread use. Methods: Demographic, pathology, staging and treatment data on 4,083 women with pT1–2, pN0–1 breast cancer referred to the BC Cancer Agency during 1989–1993 were entered into ADJ! 10-yr predicted (pred) OS, BCSS and EFS were calculated for each patient. Breast Cancer Outcomes Unit observed (obs) status at 10 years (disease event yes/no; alive; dead of disease; dead of other cause) was independently determined for each patient. ADJ! pred and BCOU obs rates were compared. Study subject pathologic characteristics were: 66% pT1, 34% pN1, 58% ER+, 37% grade 3 and 36% with lymphovascular invasion (LVI+). Three percent were age 20–35 years, 9.7% were age >75 years. Systemic therapy was: none=45%, tamoxifen (TAM) alone=30%, chemo (CT) alone=16% and CT+TAM=9%. Results: Across all 4083 patients, 10-yr pred and obs outcomes were within +/– 1% for OS (pred=71.7%, obs=72%), BCSS (pred=83.2%, obs=82.5%) and EFS (pred=71%, obs=70.1%). ADJ! overestimated EFS in women 35 yrs (pred=67.9%, obs=54.3%; p<0.002) and with LVI+ disease (pred=66.5%, obs=62.3%, p<0.001). ADJ! predicted BCSS and EFS rates within +/– 2% for patients not receiving systemic therapy or receiving TAM alone. ADJ! overestimated EFS with CT (pred=65%, obs=61.3%; p=0.056) and especially with combined CT+TAM (pred=68.1%, obs=61.7%; p=0.012). Conclusions: Overall, ADJ! performed reliably. Two factors to be added to future revisions of ADJ! were identified: age 35 and LVI+. ADJ! was overly optimistic about the outcomes of combined CT+TAM (by about 5% absolute) for OS, BCSS and EFS. Validation in large population-based databases like the BCOU, supports the translation of prediction models into practice. Supported in part by the Canadian Breast Cancer Research Alliance.

Author Disclosure

Employment or Leadership Consultant or Advisory Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Adjuvant, Inc. Adjuvant, Inc. Adjuvant, Inc.

Abstract presentation from the 2004 ASCO Annual Meeting