Purpose: To ascertain the loco-regional recurrence (LRR) rate and its major prognostic factors in patients younger than 40 and to determine the influence of age on the features of breast cancer and its treatment in two age groups: 35 years and [36-39] years.
Methods and materials: Between 1985 and 1995, 209 premenopausal women, younger than 40, were treated for early breast cancers with primary breast conserving surgery followed by radiotherapy+/-chemotherapy. Median age was 37 years with 66 patients (32%) 35 years and 143 older (68%). Median follow-up was 12 years. Tumours' characteristics were: cT1 in 75%, pN0 in 60%.
Results: LRR rate was 38% at 10 years, contralateral breast cancer rate 12%. Age was the only prognostic factor for LRR. The relative risk of LRR increased by 7% for every decreasing year of age. The annual risk of local recurrence peaked between 2 and 3 years after the initial diagnosis and returned to the level of contra-lateral breast cancer at 10 years. The younger population had infiltrating carcinomas that were significantly more commonly ductal, less commonly lobular, and of higher grade - they received chemotherapy more often.
Conclusion: Using conventional methods we could find no explanation as to why age remained the most important prognostic factor for breast cancer LRR. Known prognostic factors such as involved surgical margins seemed erased by adequate radiotherapy doses.