PURPOSE: To report the 5-year results of a randomized study comparing the
survival and cosmetic results of breast-conserving treatment with partial breast
irradiation (PBI) or conventional whole breast irradiation (WBI). METHODS AND
MATERIALS: Between 1998 and 2004, 258 selected patients with T1 N0-1mi, Grade
1-2, nonlobular breast cancer without presence of extensive intraductal component
and resected with negative margins were randomized after breast-conserving
surgery to receive 50 Gy/25 fractions WBI (n = 130) or PBI (n = 128). The latter
consisted of either 7 x 5.2 Gy high-dose-rate (HDR) multicatheter brachytherapy
(BT; n = 88) or 50 Gy/25 fractions electron beam (EB) irradiation (n = 40).
RESULTS: At a median follow-up of 66 months, the 5-year actuarial rate of local
recurrence was 4.7% and 3.4% in the PBI and WBI arms, respectively (p = 0.50).
There was no significant difference in the 5-year probability of overall survival
(94.6% vs. 91.8%), cancer-specific survival (98.3% vs. 96.0%), and disease-free
survival (88.3% vs. 90.3%). The rate of excellent to good cosmetic result was
77.6% in the PBI group (81.2% after HDR BT; 70.0% after EB) and 62.9% in the
control group (52.2% after telecobalt; 65.6% after 6-9-MV photons; p(WBI/PBI) =
0.009). CONCLUSIONS: Partial breast irradiation using interstitial HDR implants
or EB to deliver radiation to the tumor bed alone for a selected group of
early-stage breast cancer patients produces 5-year results similar to those
achieved with conventional WBI. Significantly better cosmetic outcome can be
achieved with carefully designed HDR multicatheter implants compared with the
outcome after WBI.