Breast Carcinoma Flashcards
Outline the epidemiology of breast cancer
- most common invasive cancer in women
- most common cancer-related cause of death in women
- lifetime risk 1 in 9 (women)
- 1% of breast cancers in UK are in males
- increase in incidence since 1970s
- 80% of cases occur in 50+ age group
- lower incidence in japan and africa
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What are risk factors for breast cancer?
- family history: 25% lifetime risk w/ first degree premenopausal relative
- age: avg age is 64yrs and increase in incidence >25yrs to menopause
- gender: females 100x more likely
- uninterrupted oestrogen exposure: nulliparity, no breast feeding, early menarche, late menopause, exogenous oestrogen (COCP, coil, HRT)
- obesity: inc synthesis of oestrogens in fat depots inc risk in postmenopausal obese women
- BRCA genes: BRCA1, BRCA2 - 80-90% penetrance, associated w/ ovarian Ca
- past breast cancer: irradiation from therapeautic exposure
- proliferative breast disease: inc risk in presence of sclerosing adenosis and epithelial hyperplasia, particularly artypical ductal or lobular hyperplasia
- carcinoma of contralateral breast/endometrium
- benign breast disease: duct hyperplasia
- xs alcohol consumption
What is the link with family history/genetics and breast cancer?
- 5-10% of breast cancers familial
- BRCA1 + BRCA2 - tumour suppressor genes
- germline mutations in them -> account for 85% of familial cancers
- inherited in autosomal dominant fashion
- women w/ mutations in these genes have a lifetime risk of breast cancer of between 85-100%
- also at high risk of developing ovarian cancer + so prophylactic risk-reducing bilateral mastectomy/salpingo-oophorectomy considered
- germline mutations in P53 (Li-fraumeni syndrome) less common
What are protective factors against breast cancer?
- physical activity -> reduces oestrogen + testosterone
- breastfeeding
- <20yo at first pregnancy
- diet
- NSAIDs
Asymptomatic breast cancer is usually detected on screening. But what are the clinical features of breast cancer?
- nipple discharge -> bloody, unilateral, watery, serous, milky
- breast lump -> hard, tethered, irregular, painless, irregular
- skin tethering +/- ulceration
- inflammation -> inflammatory cancers
- skin changes -> peau d’orange, puckering, dimpling, colour
- ‘eczema’ of nipple -> DCIS (Paget’s)
- lymphadenopathy
- weight loss, anorexia, bone pain, jaundice, anaemia, malignant pleural + pericardial effusions
What are differential diagnoses for a breast lump?
- fibroadenoma
- phylloides tumour
- fibrocystic breast (fibroadenosis)
- fat necrosis
- intra-ductal papilloma
- abscess
- adenoma
- atypical ductal/lobular dysplasia
- invasive breast cancer
- DCIS
- LCIS
What type of tumours are breast tumours?
- almost all malignant tumours arising in breast = invasive adenocarcinomas
- adenocarcinoma = malignant tumour of glandular epithelium
- as breast = gland
What are the two most common types of breast cancer?
- ductal carcinoma (approx 75%)
- lobular carcinoma (approx 10-15%)
NOTE: It used to be thought that ductal carcinoma arose in the ducts and lobular carcinoma arose in the lobules. We now know that this is not the case and it is accepted that virtually all breast cancers arise from epithelium lining the terminal duct lobular unit (TDLU). Therefore some people argue that the terms ‘ductal carcinoma’ and ‘lobular carcinoma’ are outdated and misleading.
other types: tubular, medullary, mucinous, myoepithelial, paget’s
What is ductal carcinoma in situ (DCIS)?
- epithelial cells show cytological changes of malignancy
- pleomorphism, hyperchromasia, inc nuclear:cytoplasmic ratios, mitotic activity present in TDLU
- however, basement membrane in tact
- cells have not invaded into the surrounding tissue
- this is a form of carcinoma in situ
- does not form a mass usually
- associated w/ microcalcifications
- usually unifocal lesion conc in 1 area of breast
Why is DCIS (ductal carcinoma in situ) not cancer?
- not invasive
- no metastatic potential
- doesn’t fill two defining criteria for malignancy
- however, if left untreated, a significant proportion will progress to invasive ductal carcinoma
- DCIS is pre-cancer
- as it’s unifocal and can progress to IDC, DCIS is surgically excised
What is invasive ductal carcinoma (IDC)?
- IDC invades through basement membrane into adjacent breast tissue + has potential to metastasise
- fulfils 2 defining criteria for a malignant tumour - it’s cancer
- usually presents as palpable breast mass
How does breast cancer spread?
- direct extension: involves skin + subcut tissue causing skin dimpling, nipple retraction + ulceration. Extension involves pec major, serratus anterior and chest wall
- lymphatic: dermal lymphatics become blocked causing cutaneous oedema pitted by sweat gland orifices known as peau d’orange appearance. Later the whole chest wall becomes a firm mass of tumour tissue. Spread to axillary + thoracic lymph nodes and later to supraclavicular, abdo and groin and opposite axillary nodes
- blood stream: blood borne spread common to lung, liver + bone (in red marrow sites eg. skull, pelvis, ribs). Sometimes in brain, ovaries and suprarenals also
What are the 4 core groups of the MDT in breast cancer?
- breast surgeons
- oncologists
- pathologists
- radiologists
then also:
- breast care nurse
- chemo nurse
- therapeutic radiographer
- research nurse
Diseases of the breasts commonly present as palpable lumps. The most likely cause of a lump depends on age. In young women, fibroadenoma and fibrocystic changes are the most common cause; cancer is much less common. In older women, cancer becomes a more important cause, although fibroadenoma and fibrocystic changes also occur.
What does triple assessment consist of?
- clinical assessment - hx + exam
- radiological - <35 US, >35 US + mammogram
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pathological:
- cystic lump -> aspirate
- residual mass -> core biopsy
- clear fluid -> discard fluid and reassure
- bloody -> cytology
- solid lump -> core biopsy
- cystic lump -> aspirate
What investigation(s) is used for breast lesions that are not palpable?
- sterotactic fine needle aspiration
- mammographically detected