Women under 35 years of age with breast cancer can have an almost 20% lower risk of their disease recurring if they are treated using a new radiotherapy regime.
These were some of the results presented today (Tuesday 26th October) by Prof Harry Bartelink and his colleagues at the 23rd Meeting of the European Society for Therapeutic Radiology and Oncology.
The analyses were based on data from the EORTC (European Organisation for Research and Treatment of Cancer) 22881 trial with updated follow-up (median follow-up: > 6years). 5318 patients with microscopically complete excision of early breast cancer using breast-conserving surgery were randomly assigned to undergo 50Gy irradiation of the whole breast either with or without an additional 16Gy of radiotherapy to the tumour bed (radiotherapy boost). 362 local recurrences were observed: 232 in the no-boost group and 130 in the boost group, demonstrating a considerable improvement in recurrence rate in women treated with boost.
The effect of the boost treatment was of greatest benefit in the younger women, with a reduction in 5-year local disease recurrence rate from 26% to 8.5% in women under 35 years of age. In women over 60 the boost dose resulted in a reduction of 5-year local recurrence rate from 3.9% to 2.1%. The addition of a boost dose caused a slight increase in early and late side effects and increases the burden on already overstretched resources. A balance therefore needs to be struck between providing optimal care with acceptable side effects whilst taking into account the availability of resources.