The variability of aggressiveness of grade 1 breast cancer.

BACKGROUND: Grade 1 breast cancer represents the lowest grade of invasive breast cancer and is associated with a low risk of recurrence and distant metastasis. However, when grade 1 breast cancer is associated with lymph node involvement, the prognosis may be worse than that of grade 1 breast cancer without lymph node involvement. METHOD: The study population included all patients who were managed in our institution between January 1, 2007 and December 31, 2013 for grade 1 breast cancer . We compared patients who had lymph node involvement to those who had no lymph node involvement. RESULTS: During the study period 291 grade 1 carcinomas were included of which 23% had associated positive lymph node involvement. Overall survival did not differ significantly between patients without lymph node involvement and those with lymph node involvement, nor was there a significant difference in the risk of local recurrence free survival. However, a significant difference was found in survival without distant metastasis with a significant level of a p at 0.029. CONCLUSION: Our findings confirm that tumor size and LVSI are strong predictors of axillary lymph node involvement, which is a key determinant of distant metastasis-free survival.