Carcinoma of the breast is the commonest form of cancer in women in most western countries: in the USA, it represents 32% of all invasive tumours in the female population. It is the second leading cause of death for women following lung cancer, accounting for 15% of all cancer deaths among women in the USA. In 2005, the American Cancer Society estimated 211,240 new cases and 40,410 female deaths from this disease (Jemal et al. 2005). Trends in incidence and mortality show that there has been a small, but steady annual increase in breast cancer (BC) incidence over the last 30 years, whereas the mortality rate has declined steadily since the beginning of the 1990s (Jemal et al. 2005). Early diagnosis is of the utmost importance to improve prognosis. Mammography (MM) is currently the best imaging modality for early detection of BC, and the results of several trials have demonstrated that mammographic screening can decrease the death rate due to BC (Daniel and Kopans 2004; Tabar et al. 2001). Nevertheless, this technique has some limitations that reduce its accuracy (Berlin 2001): not all BCs are evident on mammograms, especially in dense or dysplastic breasts (Birdwell et al. 2001), even palpable cancer may not be seen mammographically (Holland et al. 1983), it lacks of adequate specifi city in differentiating between malignant and benign lesions (Kopans 1992; Monusturi et al. 1991) and sometimes deciding which lesions require a biopsy may represent a challenge (Adler and Whal 1995). Excisional biopsy is the most effective method to determine the nature of breast abnormalities; however, the high number of biopsies in patients with benign breast lesions is a result of the low positive predictive value of MM (Kopans 1992). Breast ultrasound is largely used, but there are a few valid indications for this imaging technique, primarily involving the differentiation between cystic and solid masses and the evaluation of palpable lesions not visible on MM (Jackson 1990; Kopans 2004). Multiple areas of research have therefore been sought in order to select patients for biopsy and spare unnecessary surgical procedures. Among new imaging modalities, breast magnetic resonance imaging (MRI) and nuclear medicine breast imaging seem to be the most promising. Breast scintigraphy, also called, is a supplemental breast exam that may be used in some patients to investigate a breast abnormality. This nuclear medicine test is not a primary investigative tool for BC, but can be helpful in selected cases after mammography has been performed (Schillaci and Buscombe 2004; Schillaci 2005a).
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