Effect of age and radiation dose on local control after breast conserving treatment: EORTC trial 22881-10882

• Published in: Radiotherapy and oncology 2007-03, Vol.82 (3), p.265-271
• Main Authors: Antonini, Ninja, Jones, Heather, Horiot, Jean Claude, Poortmans, Philip, Struikmans, Henk, den Bogaert, Walter Van, Barillot, Isabelle, Fourquet, Alain, Jager, Jos, Hoogenraad, Willem, Collette, Laurence, Pierart, Marianne, Hart, Guus, Bartelink, Harry
• Format: Article
• Language: English
• Subjects: Adult; Age; Age Factors; Antineoplastic Combined Chemotherapy Protocols; Boost; Breast cancer; Breast Neoplasms - drug therapy; Breast Neoplasms - radiotherapy; Breast Neoplasms - surgery; Combined Modality Therapy; Cyclophosphamide; Dose-effect; Dose-Response Relationship, Radiation; Female; Fluorouracil; Hematology, Oncology and Palliative Medicine; Humans; Local control; Mastectomy, Segmental; Methotrexate; Middle Aged; Multivariate Analysis; Neoplasm Recurrence, Local - prevention & control; Proportional Hazards Models; Radiotherapy - methods; Radiotherapy Dosage; Risk; Treatment strategy
• ISSN: 0167-8140; 1879-0887
• DOI: 10.1016/j.radonc.2006.09.014

Abstract Purpose To determine whether the effect of an additional “boost” radiation after breast conservative therapy (BCT) on local control depends on age and evaluate the impact of a treatment policy with a threshold for age. Patients and methods We used data from EORTC 22881-10882 trial, with median follow-up of 77.4 months. Patients receiving BCT and 50 Gy whole breast irradiation were randomized to no boost and 16 Gy boost ( N = 5318). Results In univariate analysis, a boost reduced local failure by a factor of 2 ( P < 0.0001). Multivariate analysis showed local control increased with age ( P = 0.0003). There was no evidence that the relative effect of a boost on local control depends on age ( P = 0.97) However in younger patients the 5-year local failure was higher, therefore the absolute reduction was greater. If the threshold-age for boost treatment were set at 40 years, 8.4% of the study population would receive a boost, resulting in a 5-year local failure of 6.1% in the study population. Changing the threshold-age to 60 years, 67% of the study population would receive a boost and the 5-year local failure would be reduced to 4.4%. Conclusions In younger patients a boost dose resulted in a greater absolute reduction of local failure. The relative risk reduction was however similar for all ages. Applying a treatment policy with a threshold-age of 60 would result in 0.6% increase in local failure in the total study population, while sparing the boost to 1/3 of the patients.