Incorporation of Treatment Response, Tumor Grade and Receptor Status Improves Staging Quality in Breast Cancer Patients Treated with Neoadjuvant Chemotherapy
Improved staging systems that better predict survival for breast cancer patients who receive neoadjuvant chemotherapy (NAC) by accounting for clinical pathological stage plus estrogen receptor (ER) and grade (CPS+EG) and ERBB2 status (Neo-Bioscore) have been proposed. We sought to evaluate the generalizability and performance of these staging systems in a national cohort.
The National Cancer Database (2006–2012) was reviewed for patients with breast cancer who received NAC and survived ≥90 days after surgery. Four systems were evaluated: clinical/pathologic American Joint Committee on Cancer (AJCC) 7th edition, CPS+EG, and Neo-Bioscore. Unadjusted Kaplan–Meier analysis and adjusted Cox proportional hazards models quantified overall survival (OS). Systems were compared using area under the curve (AUC) and integrated discrimination improvement (IDI).
Overall, 43,320 patients (5-year OS 76.0, 95% confidence interval [CI] 75.4–76.5%) were included, 12,002 of whom had evaluable Neo-Bioscore. AUC at 5 years for CPS+EG (0.720, 95% CI 0.714–0.726) and Neo-Bioscore (0.729, 95% CI 0.716–0.742) were improved relative to AJCC clinical (0.650, 95% CI 0.643–0.656) and pathologic (0.683, 95% CI 0.676–0.689) staging. Both CPS+EG (IDI 7.2, 95% CI 6.6–7.7%) and Neo-Bioscore (IDI 9.8, 95% CI 8.0–11.6%) demonstrated superior discrimination when compared with AJCC clinical staging at 5 years. Comparison of CPS+EG with Neo-Bioscore yielded an IDI of 2.6% (95% CI 0.9–4.5%), indicating that Neo-Bioscore is the best staging system.
In a heterogenous national cohort of breast cancer patients treated with NAC and surgery, the incorporation of chemotherapy response, tumor grade, ER status, and ERBB2 status into the staging system substantially improved on the AJCC TNM staging system in discrimination of OS. Neo-Bioscore provided the best staging discrimination.
The NCDB is a joint project of the CoC of the American College of Surgeons and the American Cancer Society. The data used are derived from a de-identified NCDB PUF. The American College of Surgeons and the CoC have not verified, and are not responsible for, the analytic or statistical methods or the conclusions drawn from these data by the investigators. The authors gratefully acknowledge the support of the Mayo Clinic Department of Surgery and the Mayo Clinic Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery as substantial contributors of resources to the project. Additionally, Dr. Bergquist acknowledges the support of the Mayo Clinic Clinician Investigator Training Program for salary support. Finally, we would like to thank the Society of Surgical Oncology for affording us the opportunity to present this work at their annual Cancer Symposium in March 2017. Additionally, Dr. Bergquist acknowledges the Susan G Komen for the Cure foundation for their support of his attendance at the SSO meeting with their annual Breast Cancer research award.
Conflicts of interest
John R. Bergquist, Brittany L. Murphy, Curtis B. Storlie, Elizabeth B. Habermann, and Judy C. Boughey disclose no conflicts of interest.
The Mayo Clinic Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery provides salary support for Dr. Habermann and Dr. Murphy. Dr. Bergquist receives salary support from the Mayo Clinic Clinician Investigator Training program. The conduct and presentation of this research was independent of the above funding sources. This work has not previously, or concurrently, been submitted for publication.
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