The safety of breast-conserving therapy in patients with breast cancer aged < or = 40 years.

BACKGROUND: The objectives of this study were to study the probability of local control after breast-conserving therapy (BCT) in a large population of patients with early-stage breast cancer aged < or = 40 years and to determine which factors had prognostic value.

METHODS: All patients (n = 758) aged < or = 40 years with clinical stage I or II breast cancer who underwent BCT in general hospitals in the southern part of the Netherlands between 1988 and 2002 were selected for the current analysis. BCT included local excision of the tumor followed by irradiation of the breast. Of 758 patients, 329 patients (43%) received adjuvant systemic treatment, and 36 patients (5%) underwent a microscopically incomplete excision. The median follow-up was 8.5 years.

RESULTS: During follow-up, 95 patients developed a local recurrence without evidence of distant disease at the time the recurrence was diagnosed. Contralateral breast cancer was diagnosed in 59 patients. The 5- and 10-year actuarial local recurrence rates were 9.0% (95% confidence interval [95% CI], 6.6-11.4%) and 17.9% (95% CI, 14.1-21.7%), respectively. In a multivariate analysis, adjuvant systemic treatment reduced the risk of local recurrence (hazards ratio [HR], 0.47; 95% CI, 0.28-0.78) and contralateral breast cancer (HR, 0.46; 95% CI, 0.24-0.87) by >50%.

CONCLUSIONS: The risk of local recurrence in young patients who underwent BCT was reduced strongly by using adjuvant systemic treatment. This finding may provide an argument if favor of advising the use of systemic treatment for all patients aged < or = 40 years who undergo BCT.