Bombesin is a tumour marker elevated in small cell lung carcinomas, as well as in gastric carcinomas and retinoblastomas.

Tumour markers can be divided into:
1. Monoclonal antibodies
CA 125: Ovarian cancer, primary peritoneal cancer
CA 19-9: Pancreatic cancer
CA 15-3: Breast cancer

2. Tumour specific antigens
Prostate specific antigen (PSA): Prostatic carcinoma
Alpha-feto protein (AFP): Hepatocellular carcinoma, teratoma
Carcinoembryonic antigen (CEA): Colorectal cancer
S-100: Melanoma, schwannomas
Bombesin: Small cell lung carcinoma, gastric cancer

3. Enzymes
Alkaline phosphatase (ALP)
Neuron specific enolase (NSE)

4. Hormones
Calcitonin
Antidiuretic hormone (ADH)
Human chorionic gonadotropin (hCG)

Superior vena cava (SVC) obstruction is an oncological emergency caused by compression of the SVC and is most commonly associated with lung cancer.

Some causes of the condition include:
1. Common malignancies: non small cell lung cancer, lymphoma
2. Other malignancies: metastatic seminoma, Kaposi’s sarcoma, breast cancer
3. Aortic aneurysm
4. Mediastinal fibrosis

Clinical features of SVC obstruction include:
1. Dyspnoea: most common
2. Swelling of the face, neck, and arms: conjunctival and periorbital oedema may be seen
3. Headache: often worse in the morning
4. Visual disturbances
5. Pulseless jugular venous distension

Management options are:
1. General: dexamethasone, balloon venoplasty, stenting
2. Small cell lung cancer: chemotherapy and radiotherapy
3. Non small cell lung cancer: radiotherapy

Rasburicase should be given prior to chemotherapy in order to reduce the risk of tumour lysis syndrome (TLS). Rasburicase is a recombinant version of urate oxidase which is an enzyme that metabolizes uric acid to allantoin. Allantoin is 5-10 times more soluble than uric acid, hence, renal excretion is more effective.

TLS is a potentially fatal condition occurring as a complication during the treatment of high-grade lymphomas and leukaemias. It occurs from the simultaneous breakdown (lysis) of the tumour cells and subsequent release of chemicals into the bloodstream. This leads to hyperkalaemia and hyperphosphatemia in the presence of hyponatraemia. TLS can occur in the absence of chemotherapy, but it is usually triggered by the introduction of combination chemotherapy. Awareness of the condition is critical for its prophylactic management.

Burkitt lymphoma is a high-grade B-cell neoplasm. There are two major forms:
1. Endemic (African) form: typically involves maxilla or mandible.
2. Sporadic form: abdominal (e.g. ileocaecal) tumours are the most common form. More common in patients with HIV.

Burkitt lymphoma is associated with the c-myc gene translocation, usually t(8;14). The Epstein-Barr virus (EBV) is strongly implicated in development of the African form of Burkitt lymphoma and to a lesser extent, the sporadic form.

Management of the lymphoma is with chemotherapy. This tends to produce a rapid response which may cause TLS.

Rasburicase is a recombinant version of urate oxidase which is an enzyme that metabolizes uric acid to allantoin.

TLS is a potentially fatal condition occurring as a complication during the treatment of high-grade lymphomas and leukaemias. It occurs from the simultaneous breakdown (lysis) of the tumour cells and subsequent release of chemicals into the bloodstream. This leads to hyperkalaemia and hyperphosphatemia in the presence of hyponatraemia. TLS can occur in the absence of chemotherapy, but it is usually triggered by the introduction of combination chemotherapy. Awareness of the condition is critical for its prophylactic management.

Patients at high risk of TLS should be given IV rasburicase or IV allopurinol immediately prior to and during the first few days of chemotherapy. Allantoin is much more water soluble than uric acid and is therefore more easily excreted by the kidneys. Patients in lower-risk groups should be given oral allopurinol during cycles of chemotherapy in an attempt to avoid the condition.

TLS is graded according to the Cairo-Bishop scoring system as:
1. Laboratory tumour lysis syndrome
2. Clinical tumour lysis syndrome

In hereditary non-polyposis colonic carcinoma (HNPCC), mutations in MSH2, MSH6, PMS2 or MLH1 genes are found.
Ataxia telangiectasia – ATM gene is affected.
Familial adenomatous polyposis – APC gene is affected.
Li-Fraumeni syndrome – mutation of the TP53 tumour suppressor gene. Neurofibromatosis – mutation in or a deletion of the NF1 gene

Nausea and vomiting are the common side effects of chemotherapy. Risk factors for the development of these symptoms include age<50 years, anxiety, concurrent use of opioids, and the type of chemotherapy administered. For patients at low risk of these symptoms, drugs such as metoclopramide may be used. For high-risk patients, however, 5-HT3 receptor antagonists such as ondansetron are often effective, especially if combined with dexamethasone.

Cyclophosphamide is a cytotoxic alkylating agent that acts by causing cross-linking of DNA strands. Its major adverse effects include haemorrhagic cystitis, myelosuppression, and transitional cell carcinoma.

Cardiomyopathy is caused by doxorubicin and ototoxicity is caused by cisplatin. Alopecia and weight gain are associated with a variety of chemotherapeutic agents especially those that treat breast cancers (e.g. paclitaxel).

Lead poisoning is characterised by abdominal pain, fatigue, constipation, peripheral neuropathy (mainly motor), and blue lines on gum margin in 20% of the adult patients (very rare in children).

For diagnosis, the level of lead in blood is usually considered with levels greater than 10 mcg/dL being significant. Furthermore, the blood film shows microcytic anaemia and basophilic stippling of red blood cells. Urinary coproporphyrin is increased (urinary porphobilinogen and uroporphyrin levels are normal to slightly increased). Raised serum and urine levels of delta-aminolaevulinic acid may also be seen, making it sometimes difficult to differentiate from acute intermittent porphyria.

Hypersegmented neutrophils in the peripheral blood film is suggestive of megaloblastic changes in bone marrow.

The most likely diagnosis with anaemia, raised erythrocyte sedimentation rate (ESR), hypercalcaemia, renal impairment, and raised total protein with low albumin is multiple myeloma (MM). Protein electrophoresis will confirm the presence of monoclonal band of paraprotein. Of note, a radioisotope bone scan is not a good test for picking up the lytic lesions of MM.

Diagnosis of MM is based on the confirmation of (a) one major criterion and one minor criterion or (b) three minor criteria in an individual who has signs or symptoms of multiple myeloma.

Major criteria:
1. >30% plasma cells on bone marrow biopsy
2. Monoclonal band of paraprotein on electrophoresis: >35g/L for IgG, 20g/L for IgA, or >1g of light chains excreted in the urine per day

Minor criteria:
1. 10-30% plasma cells on bone marrow biopsy
2. Abnormal monoclonal band but levels less than listed above
3. Lytic bone lesions observed radiographically
4. Immunosuppression

The patient is most likely a case of haemophilia A which is the genetic deficiency of clotting factor VIII in blood.

Haemophilia is an X-linked recessive disorder of coagulation. Up to 30% of patients have no family history of the condition. Haemophilia A is more common than haemophilia B and accounts for 90% of the cases. In haemophilia B (Christmas disease), there is a deficiency of clotting factor IX.

Characteristic features of haemophilia include hemarthrosis, haematomas, and prolonged bleeding following trauma or surgery. Coagulation profile of a haemophiliac person shows prolonged bleeding time, activated partial thromboplastin time (APTT), thrombin time (TT), but a normal prothrombin time (PT).

Normal pO2 but decreased oxygen saturation is characteristic of methemoglobinemia.

Methemoglobinemia is a rare condition in which the haemoglobin iron is in oxidized or ferric state (Fe3+) and cannot reversibly bind oxygen. Normally, the conversion of ferrous form of iron (Fe2+) to its ferric form (Fe3+) is regulated by NADH methaemoglobin reductase, which results in the reduction of methaemoglobin to haemoglobin. Disruption in the enzyme leads to increased methaemoglobin in the blood. There is tissue hypoxia as Fe3+ cannot bind oxygen, and hence the oxygen-haemoglobin dissociation curve is shifted to the left.

Methemoglobinemia can occur due to congenital or acquired causes. Congenital causes include haemoglobin variants such as HbM and HbH, and deficiency of NADH methaemoglobin reductase. Acquired causes are drugs (e.g. sulphonamides, nitrates, dapsone, sodium nitroprusside, and primaquine) and chemicals (such as aniline dyes).

The features of methemoglobinemia are cyanosis, dyspnoea, anxiety, headache, severe acidosis, arrhythmias, seizures, and loss of consciousness. Patients have normal pO2 but oxygen saturation is decreased. Moreover, presence of chocolate-brown coloured arterial blood (colour does not change with addition of O2) and brown urine also point towards the diagnosis of methemoglobinemia.

Patients with a VTE within the previous three months, patients with AF and previous stroke or TIA or multiple other risk factors, and patients with a mitral valve replacement should be considered for bridging therapy.

The most appropriate bridging therapy in this case would be low-molecular-weight heparin (LMWH), with the last dose given not less than 24 hours prior to the procedure. Warfarin should be discontinued 5 days prior to the procedure. If the INR is still above 3 on the day prior to the procedure, vitamin K should be administered.

All of the aforementioned options may be important however cytogenetics, for detecting chromosomal abnormalities, is the single most important test to determine her disease prognosis.

Acute myeloid leukaemia (AML) is the acute expansion of the myeloid stem line, which may occur as a primary disease or follow the secondary transformation of a myeloproliferative disorder. It is more common over the age of 45 and is characterized by signs and symptoms largely related to bone marrow failure such as anaemia (pallor, lethargy), frequent infections due to neutropenia (although the total leucocyte count may be very high), thrombocytopaenia (bleeding), ostealgia, and splenomegaly.

The disease has a poor prognosis if:
1. Age of the patient >60 years
2. >20% blasts seen after the first course of chemotherapy
3. Chromosomal aberration with deletion of part of chromosome 5 or 7.

Acute promyelocytic leukaemia (APL) is an aggressive form of AML.

The upper motor neurone signs in this patient point towards a diagnosis of spinal cord compression above the level of L1 and rules out cauda equina syndrome.

Spinal cord compression is an oncological emergency and affects up to 5% of cancer patients. Extradural compression accounts for the majority of cases, usually due to vertebral body metastases. One of the most common causes of spinal cord compression is osteoarthritis. It is also more commonly seen in patients with lung, breast, or prostate cancer.

Clinical features include:
1. Back pain: the earliest and most common symptom, may worsen on lying down or coughing
2. Lower limb weakness
3. Sensory changes: sensory loss and numbness
4. Neurological signs: depending on the level of the lesion.
Lesions above L1 usually result in upper motor neurone signs in the legs. Lesions below L1 usually cause lower motor neurone signs in the legs and perianal numbness. Tendon reflexes are increased below the level of the lesion and absent at the level of the lesion.

Management options are:
1. High-dose oral dexamethasone
2. Urgent MRI for consideration of radiotherapy or surgery

Acute lymphoblastic leukaemia (ALL) is an aggressive type of blood and bone marrow cancer which can appear in childhood. Signs of childhood ALL include: Fever, Easy bruising, Petechiae, Bone or joint pain, Painless lumps in multiple areas of the body, Weakness, fatigue or paleness, and Loss of appetite. Blood tests may show elevated white blood cells, decreased values of red blood cells and low platelet count.

Haemochromatosis is an abnormally high rate of the production of haemoglobin. It is an autosomal recessive disease copied on chromosome 6. It is associated with hepatic disorders, cardiac diseases and skin pigmentation. It is treated by regular venesection.

The principal mechanism of action of taxanes (e.g. docetaxel) is the prevention of microtubule disassembly.

Other aforementioned options are ruled out because:

1. Doxorubicin: stabilizes DNA topoisomerase II complex and inhibits DNA and RNA synthesis.

2. Vincristine, vinblastine: inhibits formation of microtubules.

3. Cisplatin: causes cross-linking in DNA.

Bulbar palsy and pseudobulbar palsy are rare types of a motor neuron disease that affect the cranial motor nerves. Bulbar palsy is a lower motor neuron palsy that affects the nuclei of the 9th to 12th cranial nerves. Pseudobulbar palsy is an upper motor neuron palsy that affects the corticobulbar tracts of the 5th, 7th and 9th to 12th cranial nerves. Any condition which disrupts or damages the cranial nerve nuclei or corticobulbar tracts can cause bulbar or pseudobulbar palsy (e.g., stroke, multiple sclerosis, infections, brain stem tumours). Both bulbar and pseudobulbar palsy are seen mainly in men over 75 years old and present with progressive dysarthria and dysphagia. In addition, patients with pseudobulbar palsy present with a lack of facial expression, difficulty chewing, and emotional lability. Lower motor neuron signs (atrophy and fasciculations of the tongue, absent gag reflex) differentiate bulbar palsy from pseudobulbar palsy, which presents with upper motor neuron signs (spastic tongue, exaggerated gag, and jaw jerk reflexes). Diagnosis is mainly clinical and treatment mostly supportive with a poor prognosis. Life expectancy is around 1-3 years following diagnosis.

CML is a myeloproliferative disorder involving neoplastic proliferation of mature myeloid cells, especially granulocytes and their precursors. The non-acute symptoms of marked splenomegaly and anaemia accompanied by of fever and abdominal discomfort rules out the other conditions.

Patients with chronic myeloid leukaemia (CML) can initially be asymptomatic but as the disease progresses, they appear to have elevated WBCs with anaemia and a lower than normal platelet count. The blood test results in addition to the profound splenomegaly, which is the most common finding in patients with CML, make CML the most possible diagnosis.

Warfarin inhibits the vitamin K-dependent procoagulants II, VII, IX, and X as well as anticoagulant protein C and S. It is highly protein-bound and can be displaced by a wide variety of drugs. It has a half-life of 36-48 hours.

Bleeding is the major side effect. Easy bruising, as seen in this case, is commonly seen in patients of warfarin overdose. Grossly prolonged PT and lesser increase in APTT may be seen in such cases.

Subcutaneous (S/C) low-molecular-weight heparin (LMWH) is a preferred anticoagulant in pregnancy. Warfarin is contraindicated due to its teratogenic effects, especially in the first trimester and at term.

Pregnancy is a hypercoagulable state with the majority of VTE incidents occurring in the last trimester.

Hypercoagulability in pregnancy is caused by:
1. Increase in factors VII, VIII, X, and fibrinogen
2. Decrease in protein S
3. Uterus pressing on IVC causing venous stasis in legs

Management options include:
1. S/C LMWH preferred to IV heparin (less bleeding and thrombocytopaenia)
2. Warfarin contraindicated

There are two main reasons for using combinations of chemotherapeutic agents rather than single agents. First, different drugs exert their effects through different mechanisms, therefore, carefully combining them will increase the number of tumour cells killed in each cycle as well as decrease their chances of developing drug resistance. Second, there may be an even greater effect with drugs that are synergistic.

Aprepitant is an anti-emetic which blocks the neurokinin 1 (NK1) receptor and acts as a substance P antagonist. It is licensed for chemotherapy-induced nausea and vomiting (CINV) and for prevention of postoperative nausea and vomiting.

Nausea and vomiting are the common side effects of chemotherapy. Risk factors for the development of these symptoms include age<50 years, anxiety, concurrent use of opioids, and the type of chemotherapy administered.

The prognosis of breast cancer depends chiefly on the extent of nodal metastases.

The breast cancer TNM staging system is the most common way that doctors use to stage breast cancer. TNM stands for Tumour, Node, Metastasis. The results are combined to determine the stage of cancer for each person. There are five stages: stage 0 (zero), which is non-invasive ductal carcinoma in situ (DCIS), and stages I through IV (1 through 4), which are used for invasive breast cancer.

Staging can be clinical or pathological. Clinical staging is based on the results of tests done before surgery, which may include physical examinations, mammogram, ultrasound, and MRI scans. Pathologic staging is based on what is found during surgery to remove breast tissue and lymph nodes. In general, pathological staging provides the most information to determine a patient’s prognosis.

Prostate cancer is the most common primary tumour that metastasises to the bone.

Most common tumours causing bone metastasis (in descending order):
1. Prostate (32%)
2. Breast (22%)
3. Kidneys (16%)
4. Lungs
5. Thyroid

Most common sites of bone metastasis (in descending order):
1. Spine
2. Pelvis
3. Ribs
4. Skull
5. Long bones

Extra-nodal presentation is more common in non-Hodgkin lymphoma (NHL) than in Hodgkin lymphoma (HL). Bone marrow infiltration is more common in low-grade than in high-grade NHLs.

Low-grade NHL is predominantly a disease of older people. Most present with advanced disease, bone marrow infiltration being almost invariable. Anaemia, leucocytosis, and/or thrombocytopaenia in a patient are suggestive of bone marrow involvement. For definitive diagnosis, lymph node biopsy is sufficient.

The other aforementioned statements are ruled out because:
1. Renal impairment in NHL usually occurs as a consequence of ureteric obstruction secondary to intra-abdominal or pelvic lymph node enlargement.

2. Burkitt lymphoma is a high-grade NHL, which was first described in children in West Africa who presented with a jaw tumour, extra-nodal abdominal involvement, and ovarian tumours. It develops most often in children or young adults and is uncommon in older people.

3. High-grade lymphomas are potentially curable. They have a better prognosis and are responsive to chemotherapy unlike low-grade lymphomas, which are incurable with conventional therapy.

Red cell aplasia is commonly associated with thymomas.

Thymoma is the most common tumour of the anterior mediastinum and is usually detected between the sixth and seventh decades of life. It is associated with myasthenia gravis (30-40% of patients), red cell aplasia, and dermatomyositis. Compression of airway and cardiac tamponade are the common causes of death in thymoma.