Role of radiotherapy boost in women with ductal carcinoma in situ: a single-center experience in a series of 389 patients.

The use of adjuvant radiotherapy in ductal carcinoma in situ is accepted by most radiation oncologists worldwide; the role of a boost on the tumor bed is however more controversial. We reviewed our Institute experience in DCIS treatment, focusing on main prognostic factors and impact of radiation boost on local relapse. A total of 389 patients treated between 1990 and 2007 were retrospectively analyzed. All patients received adjuvant radiotherapy after breast-conserving surgery for a median dose of 50 Gy; 190 patients (48.8%) received and additional radiation boost on the tumor bed. At a mean follow up of 7.7 years, we recorded 26 local recurrence (6.7%). Concerning local relapse-free survival, at Cox regression univariate analyses <1 mm surgical margins (p < 0.0001) and young age (p = 0.01) emerged as significant unfavorable prognostic factors. At multivariate analysis Cox regression model, surgical margins (p < 0.001) and radiation boost (p = 0.014) resulted as the significant independent predictors of recurrence. Our experience showed the negative prognostic impact of surgical margins <1 mm and the protective role of radiation boost on LR rate. Anyway, results from ongoing prospective Phase III studies are strongly necessary to better identify high-risk DCIS patients.

Meattini I ，Livi L ，Franceschini D ，Saieva C ，Meacci F ，Marrazzo L ，Bendinelli B ，Scotti V ，De Luca Cardillo C ，Nori J ，Sanchez L ，Orzalesi L ，Bonomo P ，Greto D ，Bucciolini M ，Bianchi S ，Biti G ... -  《-》

Ductal carcinoma in situ--the influence of the radiotherapy boost on local control.

Local recurrence (LR) of ductal carcinoma in situ (DCIS) is reduced by whole-breast irradiation after breast-conserving surgery (BCS). However, the benefit of adding a radiotherapy boost to the surgical cavity for DCIS is unclear. We sought to determine the impact of the boost on LR in patients with DCIS treated at the McGill University Health Centre. A total of 220 consecutive cases of DCIS treated with BCS and radiotherapy between January 2000 and December 2006 were reviewed. Of the patients, 36% received a radiotherapy boost to the surgical cavity. Median follow-up was 46 months for the boost and no-boost groups. Kaplan-Meier survival analyses and Cox regression analyses were performed. Compared with the no-boost group, patients in the boost group more frequently had positive and <0.1-cm margins (48% vs. 8%) (p < 0.0001) and more frequently were in higher-risk categories as defined by the Van Nuys Prognostic (VNP) index (p = 0.006). Despite being at higher risk for LR, none (0/79) of the patients who received a boost experienced LR, whereas 8 of 141 patients who did not receive a boost experienced an in-breast LR (log-rank p = 0.03). Univariate analysis of prognostic factors (age, tumor size, margin status, histological grade, necrosis, and VNP risk category) revealed only the presence of necrosis to significantly correlate with LR (log-rank p = 0.003). The whole-breast irradiation dose and fractionation schedule did not affect LR rate. Our results suggest that the use of a radiotherapy boost improves local control in DCIS and may outweigh the poor prognostic effect of necrosis.

Wong P ，Lambert C ，Agnihotram RV ，David M ，Duclos M ，Freeman CR ... -  《-》

Defining negative margins in DCIS patients treated with breast conservation therapy: The University of Chicago experience.

Sahoo S ，Recant WM ，Jaskowiak N ，Tong L ，Heimann R ... -  《Breast Journal》

Radiotherapy boost dose-escalation for invasive breast cancer after breast-conserving surgery: 2093 patients treated with a prospective margin-directed policy.

To investigate the outcome of invasive early breast cancer patients that underwent breast-conserving surgery and adjuvant radiotherapy (RT), treated with a prospective margin-directed institutional policy for RT boost dose, based on final margins status (FMS). A total of 2093 patients were treated between 2000 and 2008. 10 Gy boost was prescribed in case of FMS>5mm; 16 Gy boost with FMS between 2 and 5mm; 20 Gy boost in case of FMS<2mm or positive. After a median follow up of 5.2 years, we recorded 41 local relapse (LR, 2%). Concerning LR free survival, age at diagnosis, nuclear grade, hormonal status, T-stage, adjuvant hormonal therapy and adjuvant chemotherapy emerged as significant parameters (p-values from log rank test <0.05). FMS, that directed the RT boost dose, did not have significant impact on LRFS (p=0.46). LR rates were 2.3% for FMS<2mm, 2.6% for 2-5mm FMS and 1.8% for FMS>5mm. At multivariate analysis, higher nuclear grade (p=0.045), triple negative subtype (p=0.036) and higher T-stage (p=0.02) resulted as the independent predictors of LR occurrence. Our experience showed that a margin-directed policy of RT boost dose-escalation seems to reduce the negative impact of FMS on LR, but it is not able to overcome the unfavorable effect of higher nuclear grade, higher T stage and triple negative subtype.

Livi L ，Meattini I ，Franceschini D ，Saieva C ，Meacci F ，Marrazzo L ，Gerlain E ，Desideri I ，Scotti V ，Nori J ，Sanchez LJ ，Orzalesi L ，Bonomo P ，Greto D ，Bianchi S ，Biti G ... -  《-》

Impact of boost radiation in the treatment of ductal carcinoma in situ: a population-based analysis.

To report the outcomes of a population of women with ductal carcinoma in situ (DCIS) treated with breast-conserving surgery and radiation and to evaluate the independent effect of boost radiation on the development of local recurrence. All women diagnosed with DCIS and treated with breast-conserving surgery and radiation therapy in Ontario from 1994 to 2003 were identified. Treatments and outcomes were identified through administrative databases and validated by chart review. The impact of boost radiation on the development of local recurrence was determined using survival analyses. We identified 1895 cases of DCIS that were treated by breast-conserving surgery and radiation therapy; 561 patients received boost radiation. The cumulative 10-year rate of local recurrence was 13% for women who received boost radiation and 12% for those who did not (P=.3). The 10-year local recurrence-free survival (LRFS) rate among women who did and who did not receive boost radiation was 88% and 87%, respectively (P=.27), 94% and 93% for invasive LRFS (P=.58), and was 95% and 93% for DCIS LRFS (P=.31). On multivariable analyses, boost radiation was not associated with a lower risk of local recurrence (hazard ratio = 0.82, 95% confidence interval 0.59-1.15) (P=.25). Among a population of women treated with breast-conserving surgery and radiation for DCIS, additional (boost) radiation was not associated with a lower risk of local or invasive recurrence.

Rakovitch E ，Narod SA ，Nofech-Moses S ，Hanna W ，Thiruchelvam D ，Saskin R ，Taylor C ，Tuck A ，Youngson B ，Miller N ，Done SJ ，Sengupta S ，Elavathil L ，Jani PA ，Bonin M ，Metcalfe S ，Paszat L ... -  《-》