Ki67 Frequency in Breast Cancers without Axillary Lymph Node Involvement and its Relation with Disease-free Survival

Breast cancer prognosis is influenced by several histopathology and clinical factors including expression of Ki67 which may have a predictive role in lymph node negative breast cancer patients. The aim of this study was to assess Ki67 expression in breast cancers without axillary lymph node involvement and to evaluate its prognostic value with regard to disease-free survival.

Subjects were selected from non-metastatic invasive breast cancer patients who were referred to the oncology department of Ghaem hospital during 1 April 2001 to 1 April 2008. Ki67 levels were measured using immunohistochemistry (IHC) and compared with clinicopathological features. The relation of Ki67 expression with disease-free survival was also analysed.

A total of 106 women with a mean age of 49 were examined. Some 94.3% were classified as having invasive ductal carcinomas and the mean tumour diameter at the time of diagnosis was 2.8 cm. Some 50.9% of cases were ER positive and 47.2% were PR positive. P53 expression was positive in 48.1% of the cases. According to the IHC results, only 8.5% of the patients were Her2/neu positive. Ki67 was positive in 66 (62.3%) with a significant relation to lower age (p=0.0229) and P53 positivity (p=0.005). After an average of 40-months follow up, 13 (12.3%) demonstrated recurrence, most commonly systemic. Of 13 cases with relapse, 10 patients (77%) were Ki67 positive.

In our population Ki67 appeared to be an independent prognostic factor for three-year survival. However, we stress that a survival study with a bigger sample size would help to support this conclusion.