P4-01-22: Cyclin D1 and Its Prognostic Value in Planning of Endocrine Therapy for Women of Postmenopausal Age with Breast Cancer.

Abstract

Abstract Background: Nowadays tamoxifen still remains the primary drug in breast cancer endocrine therapy. However, its application is limited due to the resistance of tumor cells. The search of adequate biomarkers is one of the most actual problems in prognosis of effectiveness of tamoxifen adjuvant therapy. The most perspective biomarker is cell cycle regulator cyclin D. Besides its central role in cell cycle regulation cyclin D1 modulates the estrogen receptors activity and can influence on the effectiveness of treatment with antiestrogenes and aromatase inhibitors. The objective of our work was to evaluate the effectiveness of tamoxifen in adjuvant therapy of hormone-receptor-positive breast cancer in women of postmenopausal age with cyclin D1 expression. Material and Methods: To evaluate the effectiveness of tamoxifen adjuvant application in women with cyclin D1-positive T1-4N0-3M0 breast cancer we have researched 2 retrospective groups of 70 patients that have been on regular medical check-up for a period of 5 years or that had previously undergone treatment. On the basis of the archive histological material we have revealed cyclin D1 in tumor cells. Results: The expression of cyclin was classified in 4 levels: negative, low, moderate and high. Patients with lack of cyclin D1 expression or with low quantitative value (according to our data less than 30%) have no neoplastic process progression throughout the 5 years of tamoxifen adjuvant therapy. These women were both with axillary lymph nodes affection and without it (+N; -N). On the contrary, women with moderate and high cyclin D1 expression (more than 30%) had a relapse of tumor and distant metastasis is prognosed in 5 years of observation (p=0,005). Moderate level of cyclin D1 expression was observed in 45 (64%) patients and 28 (62%) of them had progression with metastasis in bones, 9 (20%) metastasis in soft tissues, 2 (4%) metastasis in lungs and 6 (14%) relapse in postoperative scar. High expression was revealed in 25 (35%) women and 17 (68 %) of them had bone affection, 7 (28%) soft tissue metastasis and 2 (4%) tumor relapse in postoperative scar. Lung metastasis were not observed. The average period of tumor relapse and progression of neoplastic process in patients with cyclin D1-positive breast cancer is 20 months. Discussion: The results of our work suggest that women with hormone-receptor-positive cyclin D1-negative breast cancer on early stages have more prolonged non-relapse period during the tamoxifen adjuvant therapy. Patients with cyclin D1-positive breast cancer are less sensitive to tamoxifen treatment and in adjuvant regime should receive therapy with other effective equivalent drugs (aromatase inhibitors). Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-01-22.