الفهرس 
EPIDEMIOLOGY AND ETIOLOGICAL FACTORS OF BREAST CANCEROnly 14 pages are availabe for public view
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Abstract
B
reast cancer is the most common cancer in women worldwide, with nearly 1.7 million new cases diagnosed in 2012 (second most common cancer overall). This represents about 12% of all new cancer cases and 25% of all cancers in women. It is the fifth most common cause of death from cancer in women.
Most breast cancer subtypes are hormone-related. The natural history of the disease differs between those diagnosed before and after the menopause, which may be due to different kinds of tumour and possibly different effects of nutritional factors on hormones depending on menopausal status
A central component of the treatment of breast cancer is full knowledge of extent of the disease and biologic features. These Factors contribute to the determination of the stage of the disease, assist in the estimation of the risk that the cancer will recur and provide information that predicts response to therapy.
The scope of this study is confined to hormonal positive postmenopausal breast cancer on adjuvant tamoxifen
A central component of the treatment of breast cancer is full knowledge of extent of the disease and biologic features. These Factors contribute to the determination of the stage of the disease, assist in the estimation of the risk that the cancer will recur and provide information that predicts response to therapy.The scope of this study is confined to hormonal positive postmenopausal breast cancer on adjuvant tamoxifen
Tumor recurrence and mortality are significantly decreased by the use of 5 years of adjuvant tamoxifen both in the presence and absence of adjuvant chemotherapy. Adjuvant tamoxifen safely reduces 15-year risks of breast cancer recurrence and death. ER status was the only recorded factor importantly predictive of the proportional reductions. Hence, the absolute risk reductions produced by tamoxifen depend on the absolute breast cancer risks (after any chemotherapy) without tamoxifen.
Breast cancer growth is regulated by coordinated actions of the estrogen receptor (ER) and various growth factor receptor signaling pathways. In tumors with active growth factor receptor signaling (e.g., HER2 amplification), tamoxifen may lose its estrogen antagonist activity and may acquire more agonist-like activity, resulting in tumor growth stimulation.
The potential mechanisms for either intrinsic or acquired endocrine resistance are still poorly comprehended, but they clearly include ER-coregulatory proteins and cross-talk between the ER pathway and other GF and kinase networks. Identifying the factors and pathways responsible for this resistance, and defining ways to overcome it, are therefore important diagnostic and therapeutic challenges in current breast cancer research.
Ki67 is a nuclear protein expressed during cellular proliferation particularly during the mitosis phase
In early breast cancer, high Ki67 is an independent factor for worse prognosis as shown by significantly shorter overall and disease-free survival.
A higher Ki-67 index (≥20%) significantly correlated with other biological markers, poorer prognosis and early recurrence. It is important to take the Ki-67 index into consideration in the treatment and follow-up of breast cancer patients.
This study is a retrospective analysis studying 52 female patients with non-metastatic breast cancer presented to Clinical oncology department at Ain-Shams University hospitals. All patients’ records in the period from January 2010 to December 2015 were reviewed allowing at least two years disease free survival and overall survival follow up; all data were collected through chart analysis. Patient characteristics, clinical picture and pathological data were thoroughly collected.
In our study, some of the parameters addressed were found to be similar to worldwide incidences with little variations. Mean age at diagnosis was 57 years.
All patients had stage I-III at presentation. Stage II was the most common among study population
Near half of the patients underwent modified radical mastectomy (51.9%) the remaining underwent breast conserving surgery. Most of the patients received adjuvant and/or neoadjuvant treatment.
Most of the patients had negative axillary lymph nodes (61.5%) and 63.5% had tumor size larger than 2 cm.
Patients were stratified into two risk groups; the low risk group had ki67 <20 % and represented (67.3%) of cases and the high risk group were ≥ 20% and represented 32.7%.
Classification of patients into luminal subtypes showed that majority of cases were luminal A (53.8%), while luminal B collectively was 44.3 %.
On analysis of different prognostic factors, Compared to low ki67 group mean age at is lower for high ki67 group. Lower TNM stages in low ki67 groups.
Survival analysis was performed using Kaplan- Meier method for disease free survival (DFS) and overall survival (OS); mean DFS was found to be 55.99 months and mean OS of 59.74 months.
On analysis of impact of different prognostic factors o OS and DFS, Only luminal subtypes were found to be highly significant regarding PFS and significant with OS. Those with luminal A tumors had best outcome with mean OS 56.6 months and DFS 60.741 months
As regards relationship between ki67 groups and DFS and OS was found to be statistically insignificant.