الفهرس 
Epidemiology & Risk factors:Only 14 pages are availabe for public view
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Abstract
Breast cancer is the most common female cancer, the second most common cause of cancer death in women, and the main cause of death in women ages 40 to 59. About one-half of cases can be explained by known risk factors, such as age at menarche, first live birth, menopause, and proliferative breast disease. An additional 10 percent are associated with a positive family history (Key et al., 2011).
Approximately 232,620 new cases of invasive breast cancer are diagnosed in the United States in 2011, and 39,970 died from the disease. The lifetime probability of developing breast cancer is one in six overall (one in eight for invasive disease) (Jemal et al., 2011).
The ductal and lobular subtypes constitute the majority of all breast cancers worldwide, with the ductal subtype accounting for 40–75% of all diagnosed cases (Alessandro and Dennis, 2011).
Earlier reports suggested that the three biomarkers that are routinely used to assess breast cancers in clinical practice, that is, ER, PR, and HER2, can be used to approximate the molecular category of breast cancer, as defined by gene expression profiling. Using this approach, tumors that are ER positive and/or PR positive, and HER2 negative are most likely luminal A, those that are ER positive and/or PR positive, and HER2 positive are most likely luminal B, those that are ER negative, PR negative, and HER2 positive are most likely HER2 type, and those that are ER negative, PR negative, and HER2 negative are most likely basal-like. However, more recent studies have indicated that other markers in addition to ER, PR, and HER2 are required to more accurately approximate the molecular subtype, particularly the basal-like group (only about 70–80% of which are ‘triple negative’) and the luminal B group (only about 30% of which are HER2 positive) (Cheang et al., 2009).
At a median follow-up of 10.4 years of Venturini et al study published on 2012, which allowed them to obtain information about the long-term safety of dose-dense chemotherapy with filgrastim support. They reported 222 deaths had been recorded (104 in the FEC 14 arm and 118 in the FEC 21 arm). Estimated actuarial 10-year survival was 80% in the FEC 14 arm and 78% in the FEC 21 arm. 202 Distant relapses 94 in the FEC 14 arm and 108 in the FEC 21 arm, 68 locoregional relapses (30 in the FEC 14 arm and 38 in the FEC 21 arm), 26 second breast primary cancers (12 in the FEC 14 arm and 14 in the FEC 21 arm), 31 second primary cancers other than breast cancer (17 in the FEC 14 arm and 14 in the FEC 21 arm). However, among patients younger than 50 years, they observed a suggestion of higher efficacy associated with the FEC 14 regimen than with the FEC 21 regimen. They also updated their previous analysis of the interaction between HER2 status and treatment. Among a subset of 731 patients with available data on HER2 status, we identified a differential effect of dose density between HER2-negative patients and HER2-positive patients. Among the 628 HER2-negative patients, 10-year event-free survival was 65% in the FEC 14 arm and 60% in the FEC 21 arm. Overall survival was 85% in the FEC 14 arm and 82% in the FEC 21 However, among the 103 HER2-positive patients ’10-year event-free survival was 72% in the FEC 14 arm and 44% in the FEC 21 arm. Overall survival was 79% in the FEC 14 arm and 60% on the FEC 21 arm.