Nomogram update based on TAILORx clinical trial results - Oncotype DX breast cancer recurrence score can be predicted using clinicopathologic data

Objectives: Oncotype DX (ODX), 21-gene breast cancer (BC) assay, predicts risk of recurrence and benefits of addition of chemotherapy to hormonal therapy for early-stage BC. We previously published a nomogram/calculator that could predict ODX results without performing the test by using clinicopathologic characteristics of BC available from pathology reports. Patients with intermediate-risk (11-25) ODXRS (RS) were excluded from that nomogram. This update tests the predictive value of clinicopathologic variables for forecasting the ODXRS while including intermediate-risk-ODXRS patients and stratifying ODXRS based on recently published TAILORx clinical trial results (0-25 = low-risk, 26-100 = high-risk-ODXRS; intermediate-risk-ODXRS belongs to the low-risk category).

Material and methods: The nomogram was built on 65,754 ODX-tested ER+/HER2-/lymph-node-negative patients with 6-50 mm tumor, captured by the National Cancer Data Base (NCDB) from 2010 to 2014. Five clinicopathologic variables (age, tumor size, grade, progesterone-receptor status (PR) and BC-histologic type) were assessed with logistic regression to predict for a low-risk (0-25) or a high-risk (26-100) ODXRS. Results were validated on a separate 18,585 ODX-tested cohort from 2015.

Results: Grade and PR were the highest significant predictors of both low-risk and high-risk-ODXRS, followed by histologic type, tumor size and age. The Receiver Operator Characteristic (ROC) curve showed strong statistical model for both low-risk and high-risk-ODXRS prediction outcomes (c-index = 0.81).

Conclusions: An updated nomogram is now developed/validated on the entire population of ODX-tested patients (84,339) captured by the NCDB. The nomogram/calculator, available on-line at the UTMCK/Shiny website (https://utgsm.shinyapps.io/OncotypeDXCalculator/), will continue serving as a surrogate for BC patients for which ODX testing is not affordable, available or necessary.