Breast cancer is a transformation of normal breast cells which can turn malignant. Although far less common than in women, it is possible for men to develop breast cancer, too.
Breast cancer is the most common malignancy in women. It rarely occurs before the age of 20, and is most common between the ages of 55 and 70.
The risk of breast cancer is increased among women:
- who had their first menstrual period before the age of 12
- who entered the menopause before the age of 50
- who have had no children or who had their first child after the age of 30
- in whom abnormal cell structure was diagnosed on a breast biopsy
- who have been operated on for cancer in one breast (probable incidence of cancer in the opposite breast is approx. 6%)
- whose close relative has had breast cancer
- after the age of 50.
In women over 50 years of age, the risk increases with obesity and weight to height ratio. Women with moist cerumen (cerumen = earwax) are more prone to develop breast cancer.
Breast cancer growth and the mode of spread
Growth: Breast cancer grows slowly by doubling of tumor cells. In 15-40% of the cases, breast cancer develops at several locations within a single breast. The natural course of breast cancer is characterized by long duration. The mean survival time among patients refusing any treatment is between 2.5 and 3 years, although sometimes it may be even longer than 20 years. It has been estimated that an average tumor doubles in size about three times a year. It takes 5-8 years for a tumor to reach a diameter of 1 cm to be detected by palpation and self-examination.
Metastases: As tumor grows, it sends out tumor cells to spread elsewhere in the body via the lymph vessels or blood stream. Breast cancer starts early to produce distant metastases and that’s the reason why some believe that at the time of detection, breast cancer has already got characteristics of the disease that involves the entire body.
Tumor spread into adjacent tissue: Direct tumor spread into the skin and subcutaneous tissue causes skin dimpling or puckering, retraction of the skin and nipple, and eventually skin ulceration. Carcinoma can therefore spread directly to deeper layers, muscles and the chest wall. If cancer cells clog the lymphatic network of the skin, edema may develop that gives the skin an orange peel appearance (peau d’orange).
Spread via the blood stream and lymph vessels: Tumor cells spread via the lymph vessels to the lymph nodes in the armpit (axillary lymph nodes) and other body regions. The spread of metastases via the blood stream most frequently affects the lungs, liver and bones (skull, spine, ribs, chest bone, upper thigh bone and upper arm bone), brain, ovaries and adrenal gland.
About 95% of women dying of breast cancer have metastases.
Prognostic indicators of disease outcome
Several factors play a role in predicting the course and outcome of the disease:
- tumor size: the larger the cancer, the higher the probability of recurrence
- axillary lymph node status: lymph node involvement is a poor prognostic sign
- sensitivity to hormones: patients with hormone-sensitive cancer (cancer that has the so-called hormone receptors for female sex hormones, i.e. estrogen and progesterone) have a better prognosis and survival rates
- tumor tissue type, i.e. the grade of cell malignancy: a grade I tumor with mild abnormal cell changes has a good prognosis, while extensive changes of cells characterized by accelerated proliferation as in a grade III tumor are a poor prognostic sign.
