A new study has reported that although younger breast cancer patients are more likely to experience local recurrence (i.e., in the breast or lymph nodes) than older patients, once local recurrence occurs, younger patients have a more favorable prognosis. The study was designed to investigate whether the impact of local breast cancer recurrence on prognosis differs according to the patient's age. Young breast cancer patients are known to be more likely to develop local recurrences than older patients. It has also been shown that such local recurrences negatively affect survival, especially if the recurrence takes place within three years after treatment of the initial tumor. In the study, the authors sought to determine breast cancer-specific survival after local recurrence in younger patients (defined as under 50 years old) compared to older patients. The study included 2,130 breast cancer patients with median age 59 who were treated with lumpectomy or other breast-conserving surgery and axillary lymph node dissection between 1974 and 2003. The study groups consisted of 472 patients under 50 years of age at diagnosis and 1,658 older patients. All of the women underwent radiation treatment. Chemotherapy and/or hormonal therapy were also given after surgery and radiation, as appropriate. The women were followed for a median of 100 months. Early local recurrences were defined as those observed within 36 months of surgery; subsequent recurrences were classified as late. Primary tumor size, hormone receptor status and lymph node involvement were evenly distributed between the two groups.

Among younger patients, the five-year breast cancer-specific survival rate was found to be 92.3%; 10-year survival was 83.9%. Among older patients, the five-year cancer-specific survival rate was 94.4% and the ten-year rate was 87.6%. A total of 200 local recurrences were found during the study period, of which 52 were early local recurrences. The rate of local recurrence was significantly higher among young patients at five years (10.5% compared to 3.7% in older patients) and at 10 years (17.8% compared to 8.8%). The five-year cancer-specific survival among women who developed local recurrence was 86.8% compared to 94.7% in those who did not develop local recurrence. Similarly, the 10-year cancer-specific survival in women who developed local recurrence was 76.0% compared to 88.2% in patients who did not develop local recurrence. On the other hand, the five-year cancer-specific survival after local recurrence in younger patients was 77.6% compared to 65.7% in older patients. The authors conclude that although younger breast cancer patients experience more local recurrence than older ones, once local recurrence occurs, young patients have a more favorable prognosis. Possible reasons include (1) more aggressive treatment in young patients after local recurrence; (2) that treatment may be better sustained in young patients; and (3) biological differences in the characteristics of local recurrence.