Randomized phase II trial evaluating the efficacy of adding sequential half body irradiation (SHBI) to adjuvant chemotherapy in high-risk breast cancer patients with >10 positive lymph nodes

627 Background: Adjuvant sequential half body irradiation (SHBI) is both interesting as well as scientifically sound approach with proven efficacy in many tumors. Methods: Patients with node positive (≥10) breast cancer were randomized in this phase II trial to receive either 6 cycles of adjuvant cyclophosphamide 500 mg/m2, 5FU 500 mg/m2 and epirubicin 100 mg/m2 followed by postoperative local irradiation (Arm A) versus the same adjuvant treatment plus consolidation SHBI staring 3 weeks after end of adjuvant treatment with upper half 750cGy /5 fractions /1week then one month gap followed by the lower half for the same dose (Arm B) Results: Between November 1999 and November 2000 a total of 70 patients who met the eligibility criteria were enrolled. Arm A (n=35) and arm B (n=35) were almost comparable with the respect to different prognostic factors. There was significant improvement in the disease free survival (DFS) at 5 years in arm B. The DFS was 65±8% in arm B while it was 33±8% in arm A (log-rank test: P =0.0036). In subset analysis the difference is apparent in subgroups of patients with less potential metastatic burden, which are T2 cases and ER positive cases. The DFS at 5 years was 83% in arm B and it was 35% in arm A (P=0.0008) in T2 cases. In the subgroup of patients with ER positive tumors (n=51), the DFS at 4 years was 58% in arm B and it was 25% in arm A (P=0.0072). The complications of the addition of SHBI were mild (grades 2 and 3) and mainly gastrointestinal (vomiting, diarrhea and colic). In both arms of the study there were no life-threatening complications or treatment-related mortality. Conclusions: SHBI was found to be a well-tolerated consolidation regimen with acceptable side effects and it showed significant improvement of the DFS in breast cancer patients with ≥ 10 positive lymph nodes especially in the relative cases with good prognosis (T2-ER positive). This makes it worthy of testing in a phase III trial. No significant financial relationships to disclose.