Women 40 years or age or younger with early-stage breast cancer who receive a boost radiation dose after breast-conserving surgery and standard radiotherapy are almost twice as likely to be recurrence-free 10 years after treatment as women who do not receive a boost dose, according to a plenary presentation at the annual meeting of the American Society for Therapeutic Radiology and Oncology.

Although younger women benefited most from an extra dose of radiation, the findings demonstrated that women of all ages who had a boost dose after standard treatment were more likely to be cancer-free over a 10-year period.

The study involved 5,318 women who underwent lumpectomies and whole breast radiation treatment as part of breast conserving therapy for Stage I and Stage II breast cancer and were evaluated 10 years later. Researchers wanted to determine if a boost dose of radiation following treatment would decrease the risk of breast cancer recurrence. In addition, a subgroup of 1,725 patients were evaluated to find out the highest risk factors for localized cancer recurrence.

“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 of breast cancer recurrence to begin with,” said Harry Bartelink, MD, PhD, the senior author of the study and professor and radiation oncologist at The Netherlands Cancer Institute at Antoni van Leeuwenhoek Hospital in The Netherlands.

For patients with early-stage breast cancer, the current standard treatment involves breast conserving surgery followed by radiation therapy over a six to eight week period. In the current study, an additional boost of high-dose radiation was given after conventional radiation therapy to the surgical site.

Women who have positive or close surgical margins are at a higher risk of breast cancer recurrence compared with women who have negative margins. The study also found that early-stage breast cancer patients who were at a younger age are most likely to develop recurrence, particularly those who have positive surgical margins.

This study and previous ones have shown that young patients with early-stage breast cancer have a higher risk of breast recurrence compared with older patients because their cancer tends to be more aggressive.