Mamounas et al. JCO 2012, developed a nomogram based on a combined analysis of 3,088 patients from NSABP B-18 and B-27. These patients received neoadjuvant chemotherapy with doxorubicin/cyclophosphamide (AC) or AC followed by docetaxel. Patients who underwent mastectomy did not receive adjuvant radiation therapy, but patients undergoing lumpectomy received whole breast radiation therapy. The 10 year locoregional recurrence was 12.3% after mastectomy and 10.3% after lumpectomy and radiation therapy. Predictors of recurrence in mastectomy patients were tumor size, nodal status prior to chemotherapy, and pathologic response to chemotherapy. Predictors of recurrence in lumpectomy patients were age, clinical nodal status, and response to chemotherapy.
The 10-year locoregional recurrence based on clinical and pathologic status was as follows after mastectomy:
| ypN0, breast pCR | ypN0, No breast pCR | ypN+ |
cN0, ≤5 cm tumor | 6.5% | 6.3% | 11.2% |
cN0, >5 cm tumor | 6.2% | 11.8% | 14.6% |
cN+, ≤5 cm tumor | 0% | 10.8% | 17.0% |
cN+, >5 cm tumor | 0% | 9.2% | 22.4% |
Patient with clinical N+ disease who continue to have node positive disease after neoadjuvant chemotherapy are at the highest risk for locoregional recurrence and should be recommended to undergo adjuvant radiation therapy.
In the current RTOG 1304/NSABP B-51 trial, patients with cT1-3N1 breast cancer (positive lymph nodes proven by biopsy) who undergo neoadjuvant chemotherapy and have ypN0 disease at the time of mastectomy are being randomized to either no further RT or RT to the chest wall and regional lymph nodes. This trial will help to determine if these patients can be spared post-mastectomy radiation therapy.
