Female breast cancer is among the most common human cancers throughout the world. Its incidence is highest in the postmenopausal age group and is uncommon before the age of 25 years.
Carcinoma of the breast constitutes about 25% of all cancers in females and causes approximately 20% of cancer deaths among females. The higher the age, the more are the chances of breast lump turning out to be malignant. Thus, all breast lumps irrespective of the age of the patient must be removed surgically.
Clinically, the breast cancer appears as a solitary, painless, palpable lump detected by self–examination.
Currently, emphasis is on early diagnosis by triple technique:
- Fine Needle Aspiration Cytology (FNAC)
Additional techniques such as stereotactic biopsy and frozen section are immensely valuable to the surgeon for immediate pathological diagnosis in doubtful cases.
Risk factors- Which influence the breast cancer:
- Geographic and racial factors- are considered to be related to modifiable risk factors such as diet and environment.
- Family history- first degree relatives(mother, sister, daughter) of women with breast cancer have a 2 to 6 fold higher risk of development of breast cancer.
- Menstrual and obstetric history – women who had early menarche, nulliparity, late age of first childbirth and delayed menopause.
- FIbrocystic change- it is associated with epithelial hyperplasia having a 5-fold higher risk of developing breast cancer subsequently.
- Miscellaneous factors- include consumption of large amounts of animal fats, high-calorie foods, cigarette smoking, alcohol consumption, and exposure to ionising radiation during breast development.
General Features of Breast Cancer
Breast cancer occurs more often in the left breast than the right and is bilateral in about 4% of cases. Anatomically, the upper quadrant is the site of the tumour in half the breast cancers followed in frequency by the central portion and equally in the remaining both lower and the upper inner quadrant.
Carcinoma of the breast arises from –
- The ductal epithelium (in 90% of cases) and
- The lobular epithelium ( in 10% of cases)
Classification of the breast cancer
- Non-invasive (in situ) carcinoma
- Intraductal carcinoma
- lobular carcinoma in situ
2. Invasive carcinoma
- infiltrating (invasive) duct carcinoma-80%
- infiltrating (invasive) lobular carcinoma – 10%
- tubular (cribriform) carcinoma-6%
- medullary carcinoma- 2%
- colloid (mucinous) carcinoma- 2%
- other types: papillary carcinoma, adenoid cystic (invasive cribriform) carcinoma, secretory (juvenile) carcinoma, inflammatory carcinoma, and metaplastic carcinoma.
3. Paget’s disease of the nipple
Grading, Staging And Prognosis
Histologic grading and clinical staging of breast cancer determine the management and clinical course in these patients.
- The histologic type of tumour– It is subdivided into 3 histologic grades:
- Non-metastasising –intraductal and lobular carcinoma in-situ.
- Less commonly metastasising – medullary, colloid, papillary, tubular, adenoid cystic (invasive cribriform ) and secretory (juvenile) carcinomas.
- Commonly metastasising – infiltrating duct, invasive lobular and inflammatory carcinomas.
2. Microscopic grade-it is based on 3 features:
- Tubule formation
- Nuclear pleomorphism
- Mitotic count
3. Tumour size- there is an inverse relationship between the diameter of primary breast cancer at the time of mastectomy and long term survival.
4. Axillary lymph node metastasis- based on the number and level of lymph nodes.
5. Oestrogen and Progesterone Receptors (Er/Pr)- oestrogen is known to promote breast cancer. The presence or absence of hormone receptors on the tumour cells can help in predicting the response of breast cancer to endocrine therapy.
The American joint committee (AJC) on cancer staging has modified the TNM (primary tumour, nodal, and distant metastasis) staging proposed by UICC (UNION INTERNATIONAL FOR CONTROL OF CANCER).
STAGE TIS: in situ carcinoma (in situ lobular, Intra-ductal, Paget’s disease of the nipple without palpable lump)
STAGE 1: tumour 2cm or less in diameter no nodal spread
STAGE 2: tumour >2cm and <5cm in diameter, regional lymph nodes involved
STAGE 3A: tumour >= 5cm in diameter, regional lymph nodes involved on the same side
STAGE 3B: tumour >= 5cm in diameter, super-clavicular and infra-clavicular lymph nodes involved
STAGE 4: tumour of any size, with or without regional spread but with distant metastasis.
These factors are divided into the following 3 groups:
- Potentially pre-malignant lesions –
- Atypical ductal hyperplasia –associated with 4-5 times increased risk than women of the same age (45-55 years).
- Clinging carcinoma – is a related lesion in the duct and has a lower risk of progression to invasive cancer than in situ carcinoma.
- Fibroadenoma– is a long term risk factor for invasive breast cancer, the risk is about twice compared to controls.
2. Breast carcinoma in situ-
- ductal carcinoma in situ (comedo and non-comedo subtypes)
- breast conservative therapy is used more in carcinoma in situ which requires consideration of three factors for management: margins, the extent of disease and biological markers.
3. Invasive breast cancer is divided into 3 groups:
- routine histopathology criteria;
- hormone receptors status and
- biological indicators.
4. Molecular classification – it is based on gene profiling of breast cancer by microarray, a molecular classification has been proposed which may be four types: luminal type A OR B, HER2/neu type, BASAL-LIKE TYPE, AND NORMAL BREAST LIKE TYPE.