As evidenced in the results of EORTC trial 10853 featured in the Journal of Clinical Oncology, breast conserving treatment merged with radiotherapy diminishes the risk of local recurrence in women with ductal carcinoma in situ (DCIS).
The frequency of DCIS has been on a gradual rise over the past decades, and has been credited to increased detection through breast cancer screening using mammograms.
In the EORTC study, adjuvant radiotherapy following local removal decreased the rate of both in site and invasive local recurrences by a factor of two and led to an overall lower risk of mastectomy.
After the inclusion of radiotherapy alongside breast-conserving surgery for operable invasive breast cancer in the 1980's, numerous trials were conducted in order to examine and explore the addition of radiotherapy to local excision of DCIS. These trials revealed that radiotherapy diminished both the risk of DCIS and invasive local recurrences. As of now the long-term results of local recurrences and survival in women who undergo radiotherapy in accordance with breast conserving surgery for DCIS have been reviewed at an average follow-up of 15.8 years.
"Survival after treatment for DCIS is excellent. Therefore, the question rises whether the current treatment for DCIS (local excision and adjuvant radiotherapy of the breast) is overtreatment. To answer this question, not only long-term data about local disease recurrences and prognosis are important, but also information about the prognosis and treatment in case of recurrence,” said Dr. Mila Donker of The Netherlands Cancer Institute, Amsterdam, and lead author of this paper.
The EORTC trial 10853 was set-up and made possbile by the EORTC Breast Cancer Group and launched in 46 sites in 13 countries: The Netherlands, France, Italy, Belgium, United Kingdom, Portugal, Greece, Switzerland, Germany, South Africa, Austria, Israel, and Spain. It was a fully academic trial supported by EORTC Charitable Trust, Kankerbestrijding/KWF from The Netherlands.
From 1986 and 1996, the phase III EORTC trial 10853 observed 1010 women with total local excision of DCIS to no further treatment (503 patients) or radiotherapy (507 patients). The risk of any local recurrence was discovered to be decreased by 48% (HR: 0.52, 95%CI 0.40-0.68, P<0.001) in the patients who also underwent radiotherapy. The 15-year local recurrence-free rate was 69% for the group of patients who were only receiving breast conserving surgery, yet this increased to 82% for the group of patients who were also administered radiotherapy, and the 15-year invasive local recurrence-free rate was 84% versus 90%, respectively (HR: 0.61, 95%CI 0.42-0.87).
The differences noted in local recurrence did not lead to differences in breast cancer specific survival or overall survival, however patients with invasive local recurrence did have a considerably worse breast cancer specific survival (HR: 17.66, 95%CI 8.86-35.18) in addition to overall survival (HR: 5.17, 95%CI 3.09-8.66) than those who did not reappear. Consequently, an invasive recurrence led to a worse diagnosis.
A lower overall recover mastectomy rate following a local recurrence was also noted in the group of patients who were also administered radiotherapy, 13%, than in those patients who just underwent breast conserving surgery, 19%. Therefore, radiotherapy following breast-conserving surgery for DCIS led to an overall lower percentage of patients who were treated with a mastectomy after a local recurrence.
This study highlights the significance of performing long term follow-ups.
