Pattern of ipsilateral breast tumor recurrence after breast-conserving therapy

Area of Science:

• Oncology
• Breast Cancer Research
• Surgical Oncology

Background:

• Breast-conserving therapy (BCT) is a standard treatment for early-stage breast cancer.
• Understanding recurrence patterns is crucial for optimizing patient outcomes.
• Long-term follow-up is essential for evaluating the efficacy of BCT.

Purpose of the Study:

• To determine the incidence and prognostic factors of ipsilateral breast tumor recurrence (IBTR) after BCT.
• To analyze the temporal pattern of IBTR in a large, population-based cohort.
• To identify risk factors associated with IBTR in different age groups.

Main Methods:

• Analysis of 3595 cases of BCT in women with stage I or II breast cancer.
• Long-term follow-up data to assess IBTR as the first event.
• Stratification by age, margin status, and presence of lymph vascular space invasion (LVSI).

Main Results:

• 15-year local relapse-free survival was 90.9%.
• IBTR risk exhibited two peaks: approximately 5 years and a higher peak at 12 years.
• For women ≤40 with negative margins, adjuvant systemic therapy reduced recurrence risk 5-fold; LVSI increased risk 3-fold.
• For women >40, LVSI (HR 2.5) and lobular carcinoma in situ (HR 2.3) were key risk factors.

Conclusions:

• IBTR risk follows a bimodal pattern, with peaks at 5 and 12 years, particularly in younger women.
• In women ≤40 with clear margins, absence of adjuvant systemic therapy and presence of LVSI are independent predictors of IBTR.
• For women >40, LVSI and lobular carcinoma in situ are significant independent risk factors for IBTR.