Boost radiotherapy in young women with ductal carcinoma in situ: a multicentre, retrospective study of the Rare Cancer Network.

BACKGROUND: Outcome data in young women with ductal carcinoma in situ (DCIS) are rare. The benefits of boost radiotherapy in this group are also unknown. We aimed to assess the effect of boost radiotherapy in young patients with DCIS. METHODS: We included 373 women from 18 institutions who met the following inclusion criteria: having tumour status Tis and nodal status (N)0, age 45 years or younger at diagnosis, and having had breast-conserving surgery. 57 (15%) patients had no radiotherapy after surgery, 166 (45%) had radiotherapy without boost (median dose 50 Gy [range 40-60]), and 150 (40%) had radiotherapy with boost (60 Gy [53-76]). The primary outcome was local relapse-free survival. FINDINGS: Median follow-up was 72 months (range 1-281). 55 (15%) patients had local relapse. Local relapse-free survival at 10 years was 46% (95% CI 24-67) for patients given no radiotherapy, 72% (61-83) for those given radiotherapy without boost, and 86% (78-93) for those given radiotherapy and boost (difference between all three groups, p<0.0001). Age, margin status, and radiotherapy dose were significant predictors of local relapse-free survival. Compared with patients who had no radiotherapy, those who had radiotherapy had a decreased risk of local relapse (without boost, hazard ratio 0.33 [95% CI 0.16-0.71], p=0.004; with boost, 0.15 [0.06-0.36], p<0.0001). INTERPRETATION: In the absence of randomised trials, boost radiotherapy should be considered in addition to surgery for breast-conserving treatment for DCIS.

Enhanced renal toxicity of total body irradiation combined with radioimmunotherapy.

PURPOSE: Total body irradiation (TBI) with and without additional radioimmunotherapy (RIT) was examined for renal toxicity after stem cell transplantation. PATIENTS AND METHODS: Serum creatinine levels of 35 patients (15 female, 20 male, median age 40.5 years, range 17-60 years) after TBI alone and of 23 patients (eight female, 15 male, median age 47, range 16-58 years) after TBI with additional RIT were determined between 10/1997 and 11/1999. TBI was performed by external-beam radiotherapy in six fractions over 3 days with renal doses of 12 Gy in the TBI-alone group and 6 Gy in the group with additional RIT. The mean kidney dose due to the (188)Re-radiolabeled antibody was estimated to be 8.3 Gy (2.3-11.6 Gy). RESULTS: Within 12 months after treatment, creatinine levels increased from 77 mmol/l (SD +/- 11) to 89 mmol/l (SD +/- 20) for TBI alone and from 78 mmol/l (SD +/- 13) to 144 mmol/l (SD +/- 52) for combined TBI and RIT. CONCLUSION: Despite a 50% reduction of the external-beam contribution to the kidney dose, the application of approximately 10 GBq (188)Re-labeled anti-CD66 monoclonal antibody with a calculated renal dose of 8.3 Gy (range 2.3-11.5 Gy) led to renal toxicity, as reported previously. In the absence of a positive dose-response relationship for the (188)Re-labeled antibody, the observation may be explained by an underestimation of the biologically effective dose and the inaccuracy of the dose determination at the glomerular level.