CHICAGO–Patients managed without radiotherapy after neoadjuvant chemotherapy for breast cancer have a significantly worse outcome despite achieving a pathological complete response, a study presented at the 2015 American Society of Clinical Oncology (ASCO) annual meeting has shown.
“Local recurrence rates after neoadjuvant and adjuvant chemotherapy have been shown to be similar if adequate local therapy is performed,” said David Krug, MD, from the Department of Radiation Oncology at University Hospital Heidelberg in Germany. “Treatment response to neoadjuvant chemotherapy is an important prognostic factor and correlates with the risk of local-regional recurrence.”
For the retrospective pooled analysis, researchers analyzed data from three randomized neoadjuvant trials that included 3,370 patients with operable and non-operable breast cancer for which radiotherapy was a treatment option. Of those, 94% received radiotherapy.
Results showed that the hazard ratio for 5-year locoregional recurrence-free survival comparing patients who received radiotherapy versus those who did not was 1.77 (95% CI: 1.2, 2.6; P=0.004).
Researchers found that patients with clinically positive lymph nodes at first diagnosis had the highest rates of locoregional recurrence-free survival with radiotherapy (HR=1.85; 95% CI: 1.14, 3.01; P=0.013).
In addition, the study showed that even in patients with a pathological complete response, the 5-year locoregional recurrence-free survival rate was 94.7% with radiotherapy compared with 85.8% without radiotherapy (HR=3.48; 95% CI: 1.04, 11.59; P=0.043).
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Patients with pathological node-negative disease also had a higher rate of locoregional recurrence-free survival with radiotherapy compared with patients who received no radiotherapy (HR=2.3; 95% CI: 1.42, 3.73; P=0.001).
Dr. Krug concluded, “Patients receiving radiotherapy after neoadjuvant chemotherapy and surgery have significantly higher rates of local-regional control. The greatest absolute differences were seen in patients with clinically node-positive, pathologically node-negative, or pathologically complete response patients.”
The findings ultimately support the use of adjuvant radiotherapy in patients with or without pathological complete response after neoadjuvant chemotherapy for breast cancer.
- Krug D, Lederer B, Debus J, et al. Relationship of omission of adjuvant radiotherapy to outcomes of locoregional control and disease-free survival in patients with or without pCR after neoadjuvant chemotherapy for breast cancer: A meta-analysis on 3481 patients from the Gepar-trials. J Clin Oncol. 2015;33:(suppl; abstr 1008).