3. Majority of Breast cancers are a malignant proliferation of epithelial cells lining the ducts
or lobules of the breast.
It arises from the tissues of the breast, usually the ducts (tubes that carry milk to the nipple)
and lobules (glands that make milk).
Breast cancer is usually diagnosed in early stages, when it is a highly curable malignancy.
Breast cancer is the top cancer in women worldwide and is increasing particularly in
developing countries where the majority of cases are diagnosed in late stages.
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5. The etiology of breast cancer is unknown, but several predisposing risk factors for the
disease have been determined. 5
Mutation of BRCA1
and BRCA2 genes
Due to longer
exposure to
Estrogens
(endogenous)
All exogenous
Estrogen including
Oral Contraceptives
7. BREAST ANATOMY AND TUMOR
DEVELOPMENT
Human breast tissue is composed primarily of connective tissue and fat. There is also an
elaborate duct system within the breasts that is used during lactation.
Breast tissue has an abundant blood supply and an extensive lymphatic network. This is
important because breast cancer commonly spreads via the lymphatic system, and metastatic
disease is often discovered in the regional lymph nodes at the time of diagnosis
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9. PATHOGENESIS OF BREAST CANCER
The development of breast cancer occurs when breast cells lose their normal differentiation
and proliferation controls. Various hormones, oncogenes, and growth factors influence the
proliferation of these abnormal or tumor cells. There is strong evidence to suggest that
estrogen directly and indirectly stimulates the growth of tumor cells.
Numerous growth factors that also play a role in tumor development are secreted by the
breast cancer cells themselves. These factors can be classified as
autocrine (if they stimulate their own growth) Eg. transforming growth factor alpha (TGF-) and insulin-
like growth factors I and II (IGF-I and IGF-II)
paracrine (if they have an effect on other cells) Eg. Transforming growth factor beta (TGF-), platelet-
derived growth factor (PDGF), and procathepsin D
The exact mechanism of tumor development is not completely understood
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10. HISTOLOGY / PATHOLOGY
A breast cancer is defined by where the tumor cells originate.
The two most common histologic types of breast cancer are ductal and lobular carcinoma.
Ductal tumors
invasive ductal carcinoma – has invaded through the basement membrane of the duct
ductal carcinoma in situ (DCIS) – has not invaded through the basement membrane
Lobular tumors
invasive lobular carcinoma
lobular carcinoma in situ (LCIS)
Other types of breast cancers include inflammatory (which will be discussed later in the
chapter) and rare histologies such as tubular or medullary carcinomas or sarcomas.
The pathologic evaluation of breast lesions establishes the histologic diagnosis and presence
or absence of prognostic factors.
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17. Investigations
The triple assessment of any symptomatic breast mass –
1. Palpation (physical examination)
2. radiology – mammography, ultrasound and MRI scan
3. fine-needle aspiration cytology
Large bore core needle biopsy – differentiate invasive and non-invasive disease
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Differentiate from benign
breast masses
19. Staging
Staging is conducted to evaluate the extent of disease. Stage is based on the size of the
primary tumor (T1–4), presence and extent of lymph node involvement (N1–3), and presence
or absence of distant metastases (M0–1). Simplistically stated, these stages may be
represented as follows:
I. Early Breast Cancer
1. Stage 0: Carcinoma in situ or disease that has not invaded the basement membrane.
2. Stage I: Small primary tumor without lymph node involvement.
3. Stage II: Involvement of regional lymph nodes.
II. Locally Advanced Breast Cancer
1. Stage III: Usually a large tumor with extensive nodal involvement in which node or tumor is fixed to the chest
wall; also includes inflammatory breast cancer, which is rapidly progressive.
III. Advanced or Metastatic Breast Cancer
1. Stage IV: Metastases in organs distant from the primary tumor.
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20. Prognostic factors
Prognostic factors are measurements available at diagnosis or time of surgery that in the
absence of adjuvant therapy are associated with recurrence rate, death rate, or other clinical
outcome.
Patient age. Patients diagnosed at age younger than 35 years have a worse prognosis.
Tumor size. In general, patients with a larger tumor have a worse prognosis.
Nuclear grade describes the size and shape of the nucleus in tumor cells and the percentage of tumor
cells that are dividing. A high nuclear grade signifies that a tumor is growing quickly and indicates a
worse prognosis.
Lymph node involvement. Patients with node-positive disease have a worse prognosis.
Hormone-receptor status. Patients with negative-estrogenreceptor (ER) and negative progesterone-
receptor (PR) tumors have a worse prognosis.
HER-2/neu protein expression. Patients with HER-2/neu overexpression have a worse prognosis.
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