Boost irradiation of breast carcinoma: teletherapy vs. brachytherapy

Background: The results of adjuvant radiotherapy including a boost dose aft er breast-conserving surgery of mamma carcinoma were retrospectively analys ed to relate local tumor control, survival, and cosmetic results to the boo st technique. Material and methods: The study included 229 female patients who were treated in the period 1986-1997. Group A consisted of patients whe re the primary irradiation was hyperfractionated (two fractions per day) an d the boost was applied by reduced portals, also at two fractions per day. In group B the 'boost' was applied interstitially intraoperatively and the 'primary' irradiation followed at one fraction per day. The cosmetic result s and the late changes to the mamma were the subjects of follow-up examinat ions and were assessed using the EORTC score. Results: 129 patients formed group A. median follow-up 4.2 years, and 100 patients with median follow-up of 9.3 years formed group B. 59% of group A and 60% of group B were in sta ge pT1. 38% and 39% were in pT2, and 25% and 39% were in stage N1 or N2 (no significant differences). Tumors were mostly poorly to moderately differen tiated. The upper outer quadrant was most afflicted. Local recurrence occur red in two and live cases. lymph-node recurrence in two cases each, while t here were ten and 12 cases of distant metastases. There were no deaths in g roup A and in group B six with obvious distant metastases and eight with ot her causes of death. The cosmetic results and late side-effects( induration . teleangiectasis. ulcers) were significantly worse in the interstitial gro up B. Multivariate analysis revealed that only the total applied dose signi ficantly affected the severity of late radiation side-effects. The cosmetic results worsened with time. the tendency for lymph edemas in the irradiate d side increased. Induration decreased continuously after pure teletherapy but increased continuously after interstitial therapy. These trends did not change in either group. Conclusions: Both therapy schemes resulted in succ essful local tumor control with good cosmetic results and few side effects, but the interstitial boost therapy was clearly less favourable. Longer-ter m follow-up is required to compare the late side-effects, even further. (C) 2001 Elsevier Science Ireland Ltd. All rights: reserved.