A phase II trial of brachytherapy alone following lumpectomy for stage I or II XXXX : initial outcomes of RTOG 9517.

@entity1 @entity1137 @entity0 @entity5 @entity3831 @entity3 @entity1413 @entity1349
UNASSIGNED: 565 Background: In order to shorten the conventional 6-7 week radiation treatment time, and to treat only the tissue at greatest risk for recurrence, this phase II trial evaluates partial breast irradiation with 4-5 days of interstitial brachytherapy as an alternative to external beam. METHODS: Eligibility criteria included @entity1 (pts) with invasive <=  3cm @entity1137 , 0-3 positive axillary nodes with no extracapsular extension and at least 6 nodes removed, negative surgical margins, no residual suspicious microcalcifications, no extensive intraductal component, and no @entity1413 . After lumpectomy and axillary dissection, pts were treated with either high (34 Gy in 10 fractions over 5 days) or low (45 Gy in 3.5-5 days) dose rate ( @entity3831 or LDR) brachytherapy. Treatment volume was the lumpectomy cavity plus 2cm, except where limited by chest wall or skin. Systemic therapy was given after brachytherapy at physician discretion. Endpoints included local and regional control, disease-free (DFS) and @entity1349 ( @entity1349 ). RESULTS: One hundred pts were enrolled and one was ineligible because only a sentinel node was removed. Median follow-up is 3.7 years, range 0.6-5.7. Eighty-seven pts had T1 and 12 had T2 @entity5 . Seventy-nine were pathologically N0 and 20 were N1. The actuarial 4-year breast and nodal recurrence rate is 3% (3 pts, all @entity3831 , T1N0 x2 and T1N1) and 3% (2 pts, both @entity3831 , T1N0 x2), respectively. Distant @entity3 occurred in 6 pts, 3 T1N0 and 3 T2N1, for an actuarial 4-year rate of 6%, @entity3831 8% and LDR 4%. DFS and @entity1349 were 85% and 93% at 4 years (82% and 95% @entity3831 , 90% and 90% LDR). @entity0 developed in 3 pts, 1 @entity3831 and 2 LDR. Six pts had non-breast second primaries, 4 @entity3831 and 2 LDR. CONCLUSIONS: We conclude that partial breast brachytherapy on this RTOG trial yields excellent @entity5 control at this early analysis (<1% local failure per year), warranting support for a future phase III trial. [Table: see text].
