Cancer Flashcards
What are the 7 main aetiological factors?
Inherited conditions Chemicals Physical Diet Drugs Infective Immune Deficiency
Examples of inherited conditions that cause cancer?
Neurofibromatosis Adenomatous Polyposis Coli (FAP) Familial breast cancer (BRCA 1/2) Von-Hippel Lindau Syndrome P53 (important in all cancers - discovered via Li-Fraumeni syndrome)
Examples of chemicals that cause cancer?
Cigarette smoke --> p53 mutations Aromatic amines --> bladder cancer Benzene --> leukaemia Wood dust --> nasal adenocarcinoma Vinyl chloride --> angiosarcomas
Examples of physical factors that cause cancer?
Radiation (high energy, level of exposure/dose)
Examples of diet factors that cause cancer?
Low fibre diet –> colorectal
Smoked food –> gastric (Japan)
Examples of drugs that cause cancer?
Cytotoxic drugs –> DNA damage
Topoisomerase inhibitors –> leukaemia
Examples of infective agents that cause cancer?
HPV --> inactivates p53 --> cervical/anal EBV --> NHL Hep B --> hepatocellular Retrovirus --> T-cell lymphomas H.pylori --> MALT tumours
Examples of immune deficiencies that cause cancer?
HIV
4 main groups of presenting symptoms in cancer?
Lumps
Bleeding
Pain
Change in function
What does staging and grading indicate?
Prognosis and treatment
What does X and 0 mean in TNM staging?
X = can't be assessed 0 = no evidence
T in TNM?
Primary tumour
Tis = carcinoma in situ
T1, T2, T3, T4 = increasing size and/or local extent of tumour
N in TNM?
Regional nodes
N1, N2, N3 = increasing involvement of regional lymph nodes
(powerful indicator of probable blood-borne mass)
M in TNM?
Distant metastases
M1 = distant mets
What is grading?
Histological - how much tumour resembles normal tissue or has bizarre appearance
GX = can't be assessed G1 = well differentiated G2 = moderately differentiated G3 = poorly differentiated
Significance of stage and grade on treatment?
Breast and bowel - if lymph node involvement, they get adjuvant chemo
Uses of imaging in cancer?
Diagnosis - need histology as well
Staging - CT, MRI
Response assessment - with clinical status and tumour markers
Follow up - routine FU mostly of no proven benefit
Screening - mammography
What is the RECIST system
Used in clinical trials and clinically to assess response to treatment
Complete response (CR) Partial response (PR) Stable disease (SD) Progressive disease (PD)
CT in cancer?
Contrast can be nephrotoxic
Dose of radiation - 1 extra cancer per 1000-2000 scans
Think of pregnancy
MRI in cancer?
Neurospinal, rectal, prostate, MSK and H+N tumours
No known toxicity
No pacemaker or metal allowed! Prosthetic joints okay
Real time MR can be used
USS in cancer?
No radiation, safe, widely available and cheap
Detect mets in ‘visceral’ abdo organs + assess tumour blood flow (doppler)
Guides biopsy and therapeutic procedures
Operator dependent - less reliable for serial imaging
Nuclear medicine in cancer?
Radiosotope-labelled drugs given - distribution measured by Y-camera detection of emitted photons
Bone scintography (bone scan) - standard for skeletal mets
PET scanning in cancer?
Positron emission tomography - detects high-energy photons emitted by short-lived radioisotopes (minimse radiation) - chemically tethered to glucose/somatostatin to form a tracer –> FDG-18
Functional images –> differentiates malignant from benign (malignant takes up more glucose)
usually combined with CT - functional map with detailed anatomy
used where radical treatment appears possible but has high morbidity/mortality (NSCLC) –> may characterise involvement not picked up by size criteria alone on CT, and save patient from having big but futile surgery.
What is sensitivity and specificity of tumour markers?
Sensitivity = ability to detect only those with disease Specificity = ability to define those who are disease free
What are tumour markers used for?
Screening (only high risk individuals) Diagnosis Prognosis Response Relapse
Classes of tumour markers?
Cell surface glycoproteins Oncofoetal proteins Enzymes Intermediate metabolites Hormones Immunoglobulins Nucleic acids
CEA?
Colorectal cancer
Degree of elevation related to clinical stage.
Also elevated in smokers, hepatitis, pancreatitis or gastritis.
CA125?
Ovarian cancer
Expressed on cell surface. Not perfect sensitivity or specificity.
Also elevated in pancreatic, lung, colorectal, breast cancers (usually when disseminated to abdo cavity)
Monitoring does not increase survival and decreases QoL
Alpha fetoprotein?
Hepatocellular cancer
Usually undetectable after 1st year of life.
Also elevated in hepatitis and teratoma.
Indicates poor prognosis.
HCG?
Beta-subunit = Non-seminomatous/seminomatous testicular cancer
Also raised in gestational trophoblastic disease + pregnancy
PSA?
Prostate cancer.
Not sensitive or specific - asymptomatic screening not recommended.
Measures response and surveillance.
Also raised in BPH, rectal exam, prostatitis and UTI
Immunoglobulins?
Paraproteinaemias (e.g. myeloma and Waldenstrom’s Macroglobulinaemia, NHL)
Measured in blood or excretion in urine as light chains
Bence-Jones protein in 40-50% cases of myeloma.
Types of surgery in diagnosis and staging?
Fine needle aspiration cytology
Tru-cut needle biopsy - tumour sampled under LA
Incisional biopsy - sampled @ surgery
Excisional biopsy - whole of a mass removed
What is surgical resection of primary tumour w/curative intent?
Cancer must be localised with adequate margins of clearance to prevent recurrence
Adjuvant radio/chemo can be used –> less radical surgery
Cure can still be achieved by surgery if in local LNs sometimes
What is surgery to reduce bulk of residual disease?
Cytoreductive surgery
Ovarian cancer - shows long term benefit
What is curative surgery for metastases?
In situations where cure possible i.e. solitary lung met, sarcoma, localised liver met
Systemic therapy almost always required too
