Neo-Bioscore Improves Staging of Breast Cancer Treated With Neoadjuvant Chemotherapy


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Dr. Bergquist: Susan G. Komen Breast Cancer Award Winner

John R. Bergquist, MD, MS, MA, received the third annual Susan G. Komen Breast Cancer Research Award. This award is given to a postdoctoral breast fellow or newly trained surgical oncologist interested in breast cancer research who presents his or her work at the Society of Surgical Oncology Annual Cancer Symposium.

A new score that incorporates tumor biology and response outperforms conventional histopathologic criteria for the staging of breast cancer treated with neoadjuvant chemotherapy, finds a retrospective validation cohort study.1

Investigators led by John R. Bergquist, MD, MS, MA, a general surgery resident at the Mayo Clinic in Rochester, Minnesota, compared the CPS+EG score—which captures both initial clinical stage and postchemotherapy pathologic stage, plus estrogen receptor status and grade—and its successor, the Neo-Bioscore—which additionally includes HER2 status2—against the American Joint Committee on Cancer (AJCC) 7th Edition staging criteria.3

“Because it is well known that treatment response impacts prognosis, the difference between clinical and pathologic stage is important for understanding expected survival,” he noted during a plenary session at the 2017 Society of Surgical Oncology (SSO) Annual Cancer Symposium. “In addition, tumor grade and receptor status are known predictors associated with tumor ­biology.”


We have applied this novel [integrated discrimination improvement] metric to conclusively demonstrate that Neo-Bioscore provides the best staging classification and offers the most complete assessment of response and prognosis for patients with breast cancer after chemotherapy.
— John R. Bergquist, MD, MS, MA

Study Details

The investigators obtained data from the National Cancer DataBase for patients with invasive breast cancer who received neoadjuvant chemotherapy between 2006 and 2012.

“It is well known that studies in tertiary centers in select populations are not always generalizable,” Dr. Bergquist noted. “Therefore, our aim was to evaluate the performance of CPS+EG and Neo-Bioscore in a more diverse population treated at a wide variety of centers and compare them to the clinical and pathologic AJCC staging system.”

Analyses were based on 43,320 patients for CPS+EG score and on the subset of 12,002 patients having a recorded HER2 status for Neo-Bioscore.

Key Findings

Results showed that overall survival differed significantly for patients stratified according to the conventional AJCC clinical stage (P < .001) and pathologic stage (P < .001), he reported. Similarly, it differed significantly for patients stratified by CPS+EG score (P < .001) and Neo-Bioscore (P < .001).

Discriminatory performance of all systems as assessed using area under the curve (AUC) fell somewhat during 5 years of follow-up. But both new scores had consistently higher AUCs—roughly 0.75 to 0.65—than the AJCC clinical stage, at about 0.62 to 0.55. And from about 1 year onward, they had higher AUCs than the AJCC pathologic stage, which had values of about 0.68 to 0.63. The scores were similar to each other on this measure, with overlapping 95% confidence intervals.

Predicting Outcome With Neoadjuvant Chemotherapy

  • In a cohort study of a nationally representative sample of 43,320 patients given neoadjuvant chemotherapy for invasive breast cancer, AUC was better with Neo-Bioscore and CPS+EG score (roughly 0.75–0.65 for each) than with AJCC pathologic stage (0.68–0.63) and AJCC clinical stage (0.62–0.55).
  • At 5 years, the integrated discrimination improvement index relative to the baseline of AJCC clinical stage was about 9% for Neo-Bioscore, 7% for CPS+EG score, and 2% for AJCC pathologic stage.

When the AJCC clinical stage was used as the baseline, the Neo-Bioscore had a higher integrated discrimination improvement index compared with the CPS+EG score at most time points, and especially compared with AJCC pathologic stage, according to Dr. Bergquist.

The integrated discrimination improvement for Neo-Bioscore increased from about 1% in the first several months of follow-up to about 9% at 5 years, and that for CPS+EG score increased from about 1% to 7%. In contrast, the value for AJCC pathologic stage was low and increased minimally, going from less than 1% to roughly 2%.

Clinical Implications

“Our study demonstrates that the use of next-generation staging with incorporation of treatment response and tumor biology to stratify patients with breast cancer who have received neoadjuvant chemotherapy is generalizable to a U.S. national cohort,” Dr. Bergquist commented. “We have applied this novel [integrated discrimination improvement] metric to conclusively demonstrate that Neo-Bioscore provides the best staging classification and offers the most complete assessment of response and prognosis for patients with breast cancer after chemotherapy.”

“The advances in staging from inclusion of tumor response and tumor biology may be extrapolable to other solid tumors where neoadjuvant chemotherapy is becoming more common, for example, rectal, pancreatic, and esophageal cancers,” he added. “As we start using the 8th Edition of the AJCC staging system, which is similar to the Neo-Bioscore by incorporating grade and receptor status, we will be able to better provide individualized patient counseling tailored to each ­patient.” ■

Disclosure: Dr. Bergquist reported no potential conflicts of interest.

References

1. Bergquist JR, Murphy BL, Storlie CB, et al: CPS+EG and Neo-Bioscore are superior predictors of overall survival after neoadjuvant chemotherapy for breast cancer: A National Cancer Data Base Validation Study. 2017 Society of Surgical Oncology Annual Cancer Symposium. Abstract 8. Presented March 17, 2017.

2. Mittendorf EA, Vila J, Tucker SL, et al: The Neo-Bioscore update for staging breast cancer treated with neoadjuvant chemotherapy: Incorporation of prognostic biologic factors into staging after treatment. JAMA Oncol 2:929-936, 2016.

3. American Joint Committee on Cancer. Cancer Staging Manual. 7th Edition. Available at http://aboutcancer.com/AJCC_stage.htm. Accessed April 19, 2017.


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