MedWire News: Breast cancer patients who receive an extra dose of radiation after undergoing lumpectomy and standard radiation treatment are more likely to be free from cancer 10 years after treatment, compared with those who do not receive the boost dose, say Dutch researchers.
"The study found that the largest benefits of the boost dose of radiation after standard breast conserving treatment is seen in young women, who have a higher risk for breast cancer recurrence to begin with," said Harry Bartelink (The Netherlands Cancer Institute, Amsterdam) at the recent 2007 meeting of The American Society for Therapeutic Radiology and Oncology in Los Angeles, USA.
The current standard treatment for early-stage breast cancer involves breast-conserving surgery followed by radiation therapy to the entire breast over a 6-8 week period to kill any remaining cancer cells, note Bartelink et al.
Despite this, some patients do experience a recurrence of disease and studies have recently suggested that an additional high-dose "boost" of radiation may reduce incidence of recurrence.
To test this, Bartelink et al enrolled 5318 women with stage I or II breast cancer who underwent lumpectomy followed by whole breast irradiation of 50 Gy. In addition to the standard treatment, half of the women received an additional 16 Gy boost dose.
A total of 165 patients who received the boost dose experienced disease recurrence after 10 years of follow-up, significantly less than the 278 patients who recurred in the standard treatment group.
Bartelink et al note that women who received the dose were, therefore, 40% less likely to recur than those who did not receive the boost.
Young women seemed to benefit more from the boost dose than older women however - the absolute risk reduction was 23.9% for women aged 40 years or less and 13.5% for women aged more than 40 years.
The study also found that local failure rate for patients with negative margins at 10-years was 9.4% compared with 11.1% for patients with positive margins.
Patients with positive margins may therefore gain added benefit from a radiation boost, the researchers conclude.
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