Pathologic tumor response after neoadjuvant chemotherapy predicts risk for locoregional failure

2010 ASCO Breast Cancer Symposium

NATIONAL HARBOR, Md. — Combined results from the NSABP B-18 and NSABP B-27 trials showed that age and clinical tumor characteristics before neoadjuvant chemotherapy, and pathologic tumor response after neoadjuvant chemotherapy could predict the risk for locoregional failure in patients with breast cancer.

Eleftherios P. Mamounas, MD, a surgeon with Aultman Health Foundation in Canton, Ohio, added that the predictive factors could also suggest patients who would benefit from radiation therapy. Mamounas presented the results Saturday at the 2010 Breast Cancer Symposium.

In the two trials, patients with breast cancer were assigned to either four cycles of cyclophosphamide and doxorubicin or cyclophosphamide and doxorubicin followed by four cycles of neoadjuvant/adjuvant docetaxel. In NSABP B-18, patients older than 50 years were assigned tamoxifen following neoadjuvant chemotherapy. All patients were assigned concurrent tamoxifen in NSABP B-27.

Patients who underwent lumpectomy received breast radiation; patients who underwent mastectomy received no radiation.

Within the first 10 years of follow-up, there were 318 locoregional failures among 2,961 patients. Multivariate analysis showed that age (HR=0.79 95% CI, 0.63-0.99), initial clinical tumor size (HR=1.52; 95% CI, 1.20-1.93), initial clinical nodal status (HR=1.64; 95% CI, 1.30-2.06) and pathologic breast/nodal tumor response (HR=1.65; 95% CI, 1.07-2.56) and node+ vs. node-/pCR (HR=2.77; 95% CI, 1.82-4.21) were independent predictors for locoregional failure.

In patients who had lumpectomy and radiation therapy, Mamaounas said most locoregional failures were in breast recurrences; regional nodal recurrences were rare. Among patients who had mastectomy, researchers observed an inverse association between chest wall and pathologic breast/nodal response. – by Jason Harris

Preoperative therapy has the potential to allow us to tailor post-operative local therapy, allowing us to omit or limit radiation in many, and add or expand radiation in others. But we still need to work out the details. We need additional retrospective confirmatory work. Most importantly, we need prospective trials, but this is a start.

– Eric P. Winer, MD

Director of the Breast Oncology Center at Dana-Farber Cancer Institute

For more information:

Mamounas EP. #90. Presented at: the 2010 ASCO Breast Cancer Symposium; Oct. 1-3, 2010; National Harbor, Md.

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