For women younger than 45 years with early stage breast cancer that has not spread to the lymph nodes, opting for breast-conserving therapy (BCT) with radiation therapy was associated with a 13% higher risk of developing a local recurrence of their disease over a 20-year period compared with a mastectomy and no radiation therapy. In addition, local recurrence led to a doubling of the risk of metastasis and a risk of death that was two-thirds higher in patients who opted for breast-conserving therapy vs mastectomy.1
For women older than 45 years, no link was found between local recurrence and risk of metastasis. The researchers saw no difference in the proportion of women who died after BCT or mastectomy.
“We found that among patients older than 45 years [who received BCT], local recurrence was not associated with distant metastasis and the 20-year mortality was not different between BCT and mastectomy. These findings are in line with long-term data reported from several randomized trials, confirming that it is safe to offer older, lymph-node negative patients breast-conserving therapy and adjuvant radiation therapy,” said Tinne Laurberg, MD, of Aarhus University Hospital in Denmark, who presented these findings at ESTRO 35, the 2016 annual conference of the European Society for Radiotherapy and Oncology. Previously, little evidence existed about the risk of metastasis after recurrence for women treated with BCT.
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Laurberg added, “In contrast, among the patients younger than 45 years, local recurrence was associated with distant metastasis, and young patients treated with BCT had an increased risk of death during the 20 years, either from their disease or from other causes, compared to those who underwent mastectomy.”
“When future treatment guidelines of young lymph-node-negative patients are refined, the possibility of the negative impact of BCT on survival in these younger women should be taken into account.”
For this study, 1076 Danish women were followed for 20 years. They had early stage breast cancer diagnosed between 1989 and 1998. They were considered low-risk because their tumors were less than 5 cm in diameter and their cancer had not spread to the lymph nodes. BCT was used to treat 364 of the women, and 712 underwent mastectomy. None of the women received systemic therapies, such as chemotherapy, because of their low risk, and at that time, systemic therapy was considered to have no beneficial effect.
After 20 years, local recurrences occurred in 18% after BCT (66 women) and in 6.7% after mastectomy (55 women). Among those who underwent mastectomy, most local recurrences developed in the first 5 years among older women and in the first 10 years among younger women. Local recurrences occurred throughout the 20-year period for patients of all ages who underwent BCT.
Laurberg noted that her study was unusual because of its large size and also because of the higher proportion of younger women included. She explained that this study contrasted with former studies in that it was unbiased, all patients were lymph-node negative, treatment was only BCT or mastectomy, and the researchers had complete 20-year data on local recurrence and overall survival.
Reference
1. Laurberg T, Lyngholm C, Alsner J, et al. Long-term age dependent failure pattern after BCT vs mastectomy in low-risk breast cancer patients. Presentation at: ESTRO 35; April 29-May 3, 2016; Turin, Italy. Abstract OC-0052.
