Dan's Oncology Questions Flashcards
What sort of radiation do radiotherapy machines produce? Is it radioactive?
X-rays by targeting electromagnetic beams towards tungsten. RT is not radioactive.
What are the types of brachytherapy?
Intracavitary – the source is placed within a body cavity (used to treat oesophageal, cervical or lung cancers. Also intrauterine tubes and vaginal sources are used in the treatment of gynaecological Ca)
Interstitial – placed within tissues (rx of prostate, breast cancer, tongue and floor of mouth Ca.)
Surface mould – superficial skin lesions
What are the 3 components to biological radiation dose?
Total dose
Number of treatments (fractions) of a given dose
Overall time of treatment
What is the understanding behind planning fractions?
The same total dose given in fewer fractions has a greater effect than the same dose given over a longer time in many fractions.
However, smaller fraction sizes minimise negative effects on normal tissues.
If the fractions are too small, the overall treatment time will take too long.
What is consideration given to the overall treatment time?
Treatments over 6 to 7 weeks should be avoided to avoid repopulation of tumour cells.
What are the acute effects of radiotherapy?
These can be split into -
Non-specific effects: such as fatigue and lack of energy
Specific local effects: (self-limiting and restore after the treatment is stopped)
Skin – erythema (desquamation if severe)
Bowel – diarrhoea/colic
Bladder – frequency and dysuria
Scalp – hair loss
Mouth/pharynx – mucositis
Is lymphoedema an acute or long-term effect of radiotherapy?
Lymphoedema is a longer term effect of radiotherapy
What is desquamation and how is it treated?
The shedding of the outermost membrane (in this case skin).
Wet desquamation is when the skin starts to weep.
Desquamation is managed by the application of dressings.
What are the late effects after radical radiotherapy?
Loss of stem cell recovery potential and damage to small blood vessels causes changes that are irreversible.
Fibrosis!
• Bowel (stricture, perforation, fistula)
• Bladder (fibrosis causing frequency, haematuria, fistula)
• CNS (myelitis > paraplegia, cerebral necrosis)
• Lung (fibrosis)
What is the treatment for poor urinary flow and constipation?
Tamsulosin (alpha blocker) – improves urinary flow
Fybogel – bulk stool
How long after RT treatment does pneumonitis set in?
Pneumonitis – occurs 6-8 weeks after RT. Progressive SOB and cough. Treated with high dose steroids and oxygen
What is radical and neo-adjuvant chemo?
Radical chemo is for curative intent.
Neo-adjuvant means before surgery.
What is hand-foot syndrome?
Reddening, swelling, erythema and desquamation of the skin on the hands and the feet.
How is hand-foot syndrome managed?
Firstly, lifestyle changes (avoiding harsh chemicals, heat)
Topical analgesic emollients (lidocaine)
Which drugs are implicated in hand-foot syndrome?
Capecitabine, 5-FU, erlotinib, Sunitinib
Which chemo drugs are excreted by the Liver, and which by the kidneys?
Liver - Taxanes
Renal - Cisplatin
Which immune modifying drug is used in Gastrointestinal stromal tumours (GIST)?
Imatinib! It proved to be very successful and causes drastic remissions of PET FDG scans
(Inhibit BCR-Abl protein, cross-reacts with c-KIT product)
What are the first steps taken to control N+V of chemo?
Odansetron OR dexamethasone 8mg IV
Post –dose at home with:
Metoclopramide 10mg tds PO 14days
Dexamethasone 6mg PO
Which drug can be used for anticipatory nausea?
Lorazepam to cool nerves
How is mucositis managed?
- Good oral hygiene and painkillers (can be difficult to speak) to avoid infection.
- Laser therapy and palifermin (growth factor- stimulates growth of the mouth mucosal cells)
What are the two mechanisms of action for chemotherapy drugs?
DNA STRUCTURE - (antimetabolites, alkylating, intercalating agents),
MITOSIS - (signal transduction inhibitors, drugs inducing apoptosis)
How are methotrexate and 5-fluorouracil similar, but also how are they different?
They are both anti-metabolites.
Methotrexate inhibits folate production
5-FU incorporates itself into the DNA structure and prevents accurate replication.
How do the vinca alkaloids cause their effect?
The vinca alkyloids are spindle poisons that inhibit mitosis (vincristine, vinblastine, vindesine)
What are paclitaxel and docetaxel?(
Taxanes. These drugs also affects spindle formation.
What are the platinum based chemo drugs?
Oxaliplatin, Cisplatin, Carboplatin. They are intercalating agents and form abnormal bonds within DNA and prevent accurate replication.
(intercalating makes you richer!) –platinum is expensive
What is the purpose of separating cancers in terms of chemotherapy sensitivity?
High sensitivity cancers are given chemo as the treatment of choice.
Moderately sensitive are given chemo but as adjuvant therapy or for recurrent disease
Low sensitivity cancer will only really be given chemo in the palliation of advanced disease
Which cancers are high sensitivity and moderate sensitivity?
HIGH SENSITIVITY – Blood cancers (leukaemia, lymphoma), germ cell tumours, small cell lung cancer, myeloma, neuroblastoma, Wilms tumour
MODERATE SENSITIVITY – Breast, colorectal, bladder, ovary and cervix
LOW SENSITIVITY – Prostate, kidney, primary brain tumours, adult sarcomas, melanoma
What is the common mode of delivery of chemotherapeutic agents?
Through an indwelling central venous catheter (PICC/Hickman’s line) - cancer patients require the administration of venotoxic drugs for long periods of time.
What is a PICC line?
Peripherally inserted central catheter (enters in the antecubital fossa)
Into which veins are central lines inserted?
Large veins – Internal Jugular vein, subclavian or femoral
Hickmann lines and portacaths are inserted into the internal jugular as it is close to the surface and easy to find
(note! the only difference between a portacath and the Hickmann is the catheter externally. They are inserted the same)
Where do PICC lines lie?
They are inserted through a peripheral vein, through the subclavian and lie in the Superior vena cava
What is a portacath?
Indwelling central catheter which is tunnelled under the skin and over the collar bone and into the internal jugular vein. Blood can be taken from the portal and drugs can be administered.
It is more discrete than other CCs and does not interfere with tasks such as washing.
What are the four oncological emergencies?
Neutropenic sepsis, Hypercalcaemia, Spinal Cord Compression, SVC compression
Which cell types do chemotherapy drugs target and how does this lead to neutropenic sepsis?
Chemotherapy targets high turnover rate (dividing cells) - mucosal layers and bone marrow.
Thereby, the damage done to the mucosa by chemotherapy allows translocation of bacteria into the bloodstream > sepsis.
The damaged bone marrow leads to a reduction in neutrophil count. The neutropenia and the translocation of bacteria into the blood stream result in neutropenic sepsis.
Flora found in the gut are gram positive or negative?
Gram negative
What are the most common organisms involved in neutropenic sepsis?
Gram negative organisms! – E Coli, Klebsiella, and pseudomonas
BUT staph aureus and Strep epidermidis are also involved
What investigations and results are required for a neutropenic sepsis diagnosis?
Full blood count. A neutrophil count of <0.5x109/L with either
-temperature higher than 38oC for 1 hour / single temperature higher than 38.5oC
OR
-other signs or symptoms consistent with clinically significant sepsis
What is the management of neutropenic sepsis?
BUFALO. Antibiotic of choice TAZOCIN (pipercillin/tazobactam) should be given on suspicion of NS.
How do cancers cause hypercalcaemia?
Some cancers release parathyroid related protein (PTrP) and increase serum calcium
Which organs does PTH work on?
It targets three organs: the kidneys, the bone and the gut. It results in increase reuptake of Ca2+ by the kidneys, increased release of osteoclasts and the subsequent breakdown of bone, and the increase absorption of dietary Ca2+ from the gut.
Which cancers are most likely to cause hypercalcaemia?
- Breast cancer
- Non-small cell Lung cancer (squamous cell)
- Multiple myeloma
- Prostate cancer
What are some symptoms of hypercalcaemia?
Painful BONES, kidney STONES, psychiatric MOANS, and abdominal GROANS
Polydipsia and polyuria. Weight loss and fatigue are two non-descript symptoms that are present in hypercalcaemia.
What are the first line treatments for hypercalcaemia?
FLUIDS AND BISPHOSPHONATES
0.9% Saline 4-6L over 24hours (Patient must be monitored closely for risk of fluid overload)
Bisphosphonates (Panidronate IV)
What are some symptoms of spinal cord compression?
Back pain and neurological symptoms below the level of the compression - lower limb weakness, saddle anaesthesia, sensory loss.
This will be accompanied by constipation and urinary retention
Which cancers are most commonly associated with spinal cord compression?
Breast cancer, multiple myeloma, prostate cancer (commonly spreads to bone), lymphoma
What investigations are done for SCC?
Blood tests (check for bone marrow involvement, ALP and increased Ca2+) MRI whole spine is gold standard
What is the spinal cord compression pathway for a patient with suspected SCC?
If a patient is suspected of SCC: Lie flat Administer 16mg dexamethasone (with PPI!) Consider LMWH is reduced mobility THEN Order an urgent MRI spine THEN If MRI spine is positive for SCC: THEN Consider neurosurgical intervention THEN Radiotherapy
What are some symptoms of Superior Vena Cava Obstruction?
Fluid retention in the face, neck and arms and also a raised JVP.
Breathlessness - worse on lying supine. Pain may occur and is worse on cough.
What is the most common cause of SVCO?
Lung cancer. Any cancers in the mediastinum and chest can cause compression of the SVC
What is the management for SVCO?
16mg dexamethasone
Treat the underlying cause (obstructing malignancy/non-malignancy)
There may also be a role for SVC stents
What is tumour lysis syndrome?
A syndrome arising from the rapid breakdown of a large number of cells – usually in response to instigation of chemotherapy with a highly sensitive tumour like lymphoma or leukaemia.
What are the symptoms of tumour lysis syndrome?
It presents with extensive metabolic disturbances. Can present as AKI or cardiac arrhythmias and can be life-threatening.
Hyperphosphataemia, hyperuricaemia, hyper-something? Everything goes up apart from calcium
What are some possible causes of vomiting in cancer?
Gastric stasis, gastric outflow obstruction, oesophageal blockage, bowel obstruction, raised intracranial pressure, anxiety related
How does a patient present with gastric stasis?
Large volume of vomitus with infrequent vomiting and relief after vomiting episode. It also presents with epigastric fullness and early satiation.
If a patient presents with symptoms similar to gastric stasis but with low-volume vomiting what is a likely diagnosis?
‘Squashed stomach syndrome’ – space occupying lesion that results in the reduction in the gastric cavity
A patient presents with effortless vomiting, often in the morning, which is associated with headache. What is the most likely cause of the patients vomiting?
Raised intracranial pressure
What anti-emetic would you use to manage raised ICP vomiting?
Cyclizine
What is the mechanism of action of Haloperidol and which types of vomiting is it used to manage?
Haloperidol is a first generation anti-psychotic that can be used to control nausea and vomiting. It is a dopamine antagonist. It is mainly used to treat drug-induced and metabolic causes of nausea.
What are the three types of laxatives?
Stimulant, osmotic and bulk-forming
Name an osmotic laxative.
Lactulose, Phosphate enema. These hold water in the stool and maintain its volume and stimulating peristalsis.
What are the adverse effects of osmotic laxatives?
Flatulence, abdo cramps and nausea. Diarrhoea is of course an adverse effect.
What type of laxative is Senna?
Senna is a Stimulant
How do bulk-forming and stimulant laxatives work differently?
Bulk forming laxatives draw water into the stool and increase its volume which in turn stimulates peristalsis.
Stimulant laxatives act on the nerve plexus and promote peristalsis (they also alter water and electrolyte secretion!)
When are laxatives contraindicated?
Whenever obstruction is expected!
Which is the most common gynaecological cancer?
Endometrial
What is the typical demographic for endometrial cancer?
Obese nulliparous women (with a tendency of CVD or DM), with a family history of endometrial cancer.
What are the risk factors of endometrial cancer?
Obesity
Diabetes
Early menarche, late menopause
Unopposed oestrogen HRT
Tamoxifen – partial agonist affect on endometrium which can cause proliferation
FHX of endometrial, breast cancer, colorectal
What is the most common type of uterine cancer?
Adenocarcinoma is around 90%
Where are common sites of spread of endometrial cancer?
Lungs and bone
What is the classic presentation of endometrial cancer?
Pre-Menstrual Bleeding is endometrial cancer until proven otherwise.
On examination, uterus may feel bulky and vaginal discharge or bleeding may be apparent
Irregular, heavy or inter-menstrual bleeding, is <40
What percentage of women presenting with PMB have malignancy?
Only 10%
What is stage 2 endometrial cancer (FIGO)?
Spread to the cervix. Spread to other pelvic structures is stage 3.
What are the investigations for endometrial cancer?
Transvaginal ultrasound and pipelle
Hysteroscopy and biopsy if endometrial thickening
What is the treatment of stage 1 endometrial cancer?
Total abdominal hysterectomy with salpingo-oopherectomy is the treatment of choice for localised disease.