ESTRO 2016: New Study Sheds Light on Mastectomy vs Breast-Conserving Therapy in Older vs Younger Patients With Early Breast Cancer
New research presented at the ESTRO 35 Conference on April 30 (Abstract OC-0052) has shown women aged younger than 45 years with early-stage breast cancer that had not spread to the lymph nodes and who opted for breast-conserving therapy with radiation therapy had a 13% higher risk of developing a local recurrence of their disease over a 20-year period than women who had a mastectomy and no radiation therapy. Furthermore, local recurrence doubled the risk of metastasis. The risk of death was approximately two-thirds higher for breast-conserving therapy patients compared to mastectomy patients.
By contrast, among women aged over 45, there was no link between local recurrence and the risk of metastasis, and there was no difference in the proportion of these women who died after breast-conserving therapy or mastectomy.
Study Details
Researchers from Aarhus University Hospital in Aarhus, Denmark, followed 1,076 Danish women for 20 years. The women had been diagnosed between 1989 and 1998 and were classified as low risk because they had tumors smaller than 5 cm in diameter and the cancer had not started to spread to the lymph nodes. A total of 364 women received breast-conserving therapy, and 712 had a mastectomy. None of the women received systemic therapies.
After 20 years, the proportion of local recurrences was 18% after breast-conserving therapy (66 women) and 6.7% after mastectomy (55 women). Among the women who had a mastectomy, most local recurrences occurred in the first 5 years in the older women, and in the first 10 years for the younger women. Breast-conserving therapy patients of all ages had a local recurrence of their disease throughout the 20-year period.
Tinne Laurberg, MD, said, “We found that among patients older than 45 years receiving breast-conserving therapy, local recurrence was not associated with distant metastasis and the 20-year mortality was not different between breast-conserving therapy 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.”
“In contrast, among the patients younger than 45 years, local recurrence was associated with distant metastasis, and young patients treated with breast-conserving therapy 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 breast-conserving therapy on survival in these younger women should be taken into account.”
Dr. Laurberg said that the study was unusual not just for its large size, but also because of the high proportion of young women included in it. “Data concerning the long-term effect of breast-conserving therapy vs mastectomy among young patients is very limited. In six randomized controlled trials comparing mastectomy and breast-conserving therapy, all studies had a low proportion of young breast cancer patients included (between 12%–23%), making it hard to draw any conclusion for this subgroup. Few cohort studies, restricted to young breast cancer patients, have been published, but these are limited by the inclusion of a mixture of different cancer stages, by the variety of adjuvant systemic treatments used, and by an average follow-up time of less than 10 years in almost all of the studies. In contrast to former studies, our study of young breast cancer patients was unbiased; all patients were lymph-node negative; they received only breast-conserving therapy or mastectomy; and we had complete 20-year data on local recurrence and overall survival.”
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