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.

The diagnosis for the aforementioned case is thrombotic thrombocytopenic purpura (TTP). TTP is classically characterised as a pentad of thrombocytopaenia, microvascular haemolysis, fluctuating neurological signs, renal impairment, and fever.

The differential diagnosis for severe thrombocytopaenia is immune thrombocytopenic purpura (ITP). ITP is more common than TTP. However, a patient of ITP would not present with the range of symptoms seen in this scenario.

In TTP, there is deficiency of a protease which breaks down large multimers of von Willebrand factor. This leads to abnormally large and sticky multimers of von Willebrand factor which cause platelets to clump within the vessels.

Untreated TTP has a mortality rate of up to 90%. Therefore, rapid plasma exchange (PEX) may be a life-saving intervention. Platelet transfusion in TTP is only indicated if there is an ongoing life-threatening bleed. Intravenous methylprednisolone is indicated after treatment with PEX has been completed. There is no current role of intravenous immunoglobulin in the routine management of TTP. However, there have been reports of its successful use in PEX- and steroid-refractory cases. Intravenous argatroban is indicated in heparin-induced thrombocytopaenia (HIT), but there is no history of recent heparin administration or hospitalisation in this patient nor are the clinical signs consistent with HIT.

Management options for TTP include PEX as the treatment of choice. Steroids and immunosuppressants are also given. Antibiotics are not recommended as they may worsen the outcome of the disease. For cases resistant to PEX and pharmacologic therapy, vincristine is given.

The patient has paroxysmal nocturnal haemoglobinuria (PNH) complicated by acute hepatic vein thrombosis (Budd–Chiari syndrome).

PNH is an acquired clonal disorder of haematopoietic stem cells, characterised by variable combination of intravascular haemolysis, thrombosis, and bone marrow failure. Diagnosis is made by flow cytometric evaluation of blood, which confirms the CD55 and CD59 deficiencies and deficiency of expression of other GPI-linked proteins. This test is replacing older complement-based assays such as the Ham test and sucrose lysis test.

IgG4-related disease (IgG4-RD) is a fibro-inflammatory condition that can affect nearly any organ system: the pancreas, biliary tree, salivary glands, periorbital tissues, kidneys, lungs, lymph nodes, meninges, aorta, breast, prostate, thyroid, pericardium, and skin. The histopathological features are similar across organs, regardless of the site. IgG4-RD is analogous to sarcoidosis, in which diverse organ manifestations are linked by similar histopathological characteristics. Raised concentrations of IgG4 in tissue and serum can be helpful in diagnosing IgG4 disease, but neither is a specific diagnostic marker.

Some IgG4-RDs are:
1. Autoimmune pancreatitis
2. Riedel’s Thyroiditis
3. Mediastinal and Retroperitoneal Fibrosis
4. Periaortitis/periarteritis/Inflammatory aortic aneurysm
5. Kuttner Tumour (submandibular glands)
6. IgG4-related Mikulicz disease (lacrimal, parotid, and submandibular glands)

Deletion of part of chromosome 5 or 7 is a poor prognostic feature for acute myeloid leukaemia (AML).

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 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.

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.

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)

Leukemoid reaction has a high LAP score.

Leukemoid reaction refers to leucocytosis occurring as a physiological response to stress or infection which may be mistaken for leukaemia, especially chronic myeloid leukaemia (CML). Leucocytosis occurs, initially, because of accelerated release of cells from the bone marrow and is associated with increased count of more immature neutrophils in the blood (left-shift). In order to differentiate, LAP score is used. Leukocytic alkaline phosphatase (ALP) activity is high in a leukemoid reaction but low in CML.

LAP score is high in:
1. Leukemoid reaction
2. Infections
3. Myelofibrosis
4. Polycythaemia rubra vera
5. Steroids, Cushing’s syndrome
6. Pregnancy, oral contraceptive pill

LAP score is low in:
1. CML
2. Pernicious anaemia
3. Paroxysmal nocturnal haemoglobinuria (PNH)
4. Infectious mononucleosis

Night sweats are a B symptom in Hodgkin lymphoma (HL) and imply a poor prognosis.

HL is a malignant proliferation of lymphocytes characterised by the presence of distinctive giant cells known as Reed-Sternberg cells. It has a bimodal age distribution being most common in the third and seventh decades of life.

Staging of HL is done according to the Ann Arbor staging system:

Stage
I: Single lymph node region (I) or one extra lymphatic site (IE)

II: Two or more lymph node regions on same side of the diaphragm (II) or local extra lymphatic extension plus one or more lymph node regions on same side of the diaphragm (IIE)

III: Lymph node regions on both sides of the diaphragm (III) which may be accompanied by local extra lymphatic extension (IIIE)

IV: Diffuse involvement of one or more extra lymphatic organs or sites

Suffix
A: No B symptoms

B: Presence of at least one of the following: unexplained weight loss >10% baseline during 6 months before staging; recurrent unexplained fever >38°C; recurrent night sweats—poor prognosis.

5–15% of the cases of polycythaemia vera progress to myelofibrosis or acute myeloid leukaemia (AML).

Polycythaemia vera (PV), also known as polycythaemia rubra vera, is a myeloproliferative disorder caused by clonal proliferation of marrow stem cells leading to an increase in red cell volume, often accompanied by overproduction of neutrophils and platelets. It has peak incidence in the sixth decade of life, with typical features including hyperviscosity, pruritus, splenomegaly, haemorrhage (secondary to abnormal platelet function), and plethoric appearance.

Some management options of PV include lose-dose aspirin, venesection (first-line treatment), hydroxyurea (slightly increased risk of secondary leukaemia), and radioactive phosphorus (P-32) therapy.

In PV, thrombotic events are a significant cause of morbidity and mortality. 5–15% of the cases progress to myelofibrosis or AML. The risk of having AML is increased with chemotherapy treatment.

Polycythaemia vera (PV) is associated with a low ESR.

PV, also known as polycythaemia rubra vera, is a myeloproliferative disorder caused by clonal proliferation of marrow stem cells leading to an increase in red cell volume, often accompanied by overproduction of neutrophils and platelets. It has peak incidence in the sixth decade of life, with typical features including hyperviscosity, pruritus, splenomegaly, haemorrhage (secondary to abnormal platelet function), and plethoric appearance. PV is associated with a low ESR.

Some management options of PV include lose-dose aspirin, venesection (first-line treatment), hydroxyurea (slightly increased risk of secondary leukaemia), and radioactive phosphorus (P-32) therapy.

In PV, thrombotic events are a significant cause of morbidity and mortality. 5–15% of the cases progress to myelofibrosis or acute myeloid leukaemia (AML). The risk of having AML is increased with chemotherapy treatment.

Waldenström’s macroglobulinemia (also called lymphoplasmacytic lymphoma) is an uncommon type of non-Hodgkin lymphoma seen in older people. It is a lymphoplasmacytoid malignancy characterised by the secretion of a monoclonal IgM paraprotein. Its features include weight loss and lethargy; monoclonal IgM paraproteinemia; hyperviscosity syndrome leading to bilateral central retinal vein occlusion (CRVO) and hence, visual disturbances; hepatosplenomegaly and lymphadenopathy; and cryoglobulinemia. It is not, however, associated with bone pain.

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

A translocation between chromosome 15 and 17 is seen in acute promyelocytic leukaemia (APL), which is known to carry a good 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 poor prognosis if:

The disease has 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.

APL is an aggressive form of AML. It is associated with t(15;17) and has a good prognosis. The general age of presentation is less than that in other types of AML (average age is 25 years old). On blood film, abundant Auer rods are seen with myeloperoxidase staining. Thrombocytopaenia or DIC is seen in patients presenting with this disease.

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.

Carcinoembryonic antigen (CEA) is a known tumour marker for colorectal cancer. It is not used diagnostically, but in patients with a known diagnosis of colorectal cancer associated with raised CEA levels, it can be used to monitor disease activity and help with the early identification of disease recurrence.

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)

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.

Haemophilia B (Christmas disease), is the deficiency of clotting factor IX and is inherited in an X-linked recessive pattern. The factor IX level dictates the disease severity and established arthropathy is usually seen in those with severe disease.

The aforementioned patient’s history and presentation is consistent with the development of hemarthrosis. Joint aspiration is not recommended. The treatment, therefore, should be intravenous replacement of the deficient clotting factor with plasma-derived factor IX concentrate.

The other listed options are ruled out because:
1. Joint aspiration is not preferred over the administration of clotting factor as the first step of management.
2. DDAVP (desmopressin) can increase factor VIII levels transiently in those with mild haemophilia A and is useful prior to minor surgical procedures in such patients.
3. Cryoprecipitate is rich in fibrinogen, factor VIII, and von Willebrand factor and is used in the treatment of haemophilia A.

CXR, blood, and urine tests should be carried out initially to exclude an underlying malignancy. If these are normal, a CT scan of abdomen and pelvis should be arranged as the patient’s age is >40 years. Antiphospholipid antibodies should also be checked for the first unprovoked DVT/PE. There is no history, however, to support an inherited thrombophilia.

The National Institute for Health and Care Excellence (NICE) published guidelines in 2012 for the investigation and management of DVT. If a patient is suspected of having DVT, a two-level DVT Wells score should be used:

DVT likely: 2 points or more
DVT unlikely: 1 point or less

This system of points is based on the following clinical features:
1. Active cancer (treatment ongoing, within six months, or palliative)—1
2. Paralysis, paresis, or recent plaster immobilisation of the lower extremities—1
3. Recently bedridden for three days or more, or major surgery within 12 weeks requiring general or regional anaesthesia—1
4. Localised tenderness along the distribution of the deep venous system—1
5. Entire leg swollen—1
6. Calf swelling at least three cms larger than the asymptomatic side—1
7. Pitting oedema confined to the symptomatic leg—1
8. Collateral superficial veins (non-varicose)—1
9. Previously documented DVT—1
10. An alternative diagnosis is at least as likely as DVT—2

If two points or more—DVT is ‘likely’
If one point or less—DVT is ‘unlikely’

Management

1. LMWH or fondaparinux should be given initially after a DVT is diagnosed.
2. A vitamin K antagonist such as warfarin should be given within 24 hours of the diagnosis.
3. LMWH or fondaparinux should be continued for at least five days or until the international normalised ratio (INR) is 2.0 or above for at least 24 hours. LMWH or fondaparinux is given at the same time as warfarin until the INR is in the therapeutic range.
4. Warfarin should be continued for at least three months. At three months, clinicians should assess the risks and benefits of extending the treatment.
5. Consider extending warfarin beyond three months for patients with unprovoked proximal DVT if their risk of VTE recurrence is high and there is no additional risk of major bleeding. This essentially means that if there is no obvious cause or provoking factor (surgery, trauma, significant immobility, etc.), it may be implied that the patient has a tendency to thrombose and should be given treatment longer than the normal of three months. In practice, most clinicians give six months of warfarin for patients with an unprovoked DVT/PE.
6. For patients with active cancer, LMWH should be used for six months.

As both malignancy and thrombophilia are obvious risk factors for DVT, therefore, all patients with unprovoked DVT/PE who are not already known to have cancer should undergo the following investigations:
1. Physical examination (guided by the patient’s full history)
2. Chest X-ray
3. Blood tests (full blood count, serum calcium, and liver function tests) and urinalysis
4. Testing for antiphospholipid antibodies
5. Testing for hereditary thrombophilia in patients who have had unprovoked DVT/PE and have a first-degree relative who has a history of DVT/PE.

The dose is calculated, using the conversion factor, as follows:

(Conversion factor used to convert oral morphine to subcutaneous diamorphine = Divide the total daily dose of oral morphine by 3)
Hence,
60mg*2 = 120mg
120mg/3 = 40mg

The side effects of opioids can be transient or persistent, and these include constipation, nausea, and drowsiness. Therefore, all patients taking opioids should also be prescribed a laxative and an anti-emetic (if the nausea is persistent). Dose-adjustment may be necessary in cases of persistent drowsiness. Moreover, strong opioids can also provide quick relief from metastatic bone pain, as compared to NSAIDs, bisphosphonates, and radiotherapy.

Philadelphia translocation, t(9;22), is a marker of poor prognosis in acute lymphoblastic leukaemia (ALL).

ALL is the malignancy of lymphoid progenitor cells affecting B or T cell lineage. This results in the arrest of lymphoid cell maturation and proliferation of immature blast cells (lymphoblasts), leading to bone marrow and tissue infiltration.

ALL is the most common type of childhood cancers. Its peak incidence is between two to three years of age.

Acute B lymphoblastic leukaemia (B-ALL) is the most common type of ALL, involving overproduction of B-cell lymphoblasts. It is manifested by low initial WCC and is associated with a good prognosis.

Poor prognostic factors for ALL include:
1. Pre-B cell or T-cell ALL (T-ALL)
2. Philadelphia translocation, t(9;22)
3. Age <2 years or >10 years
4. Male sex
5. CNS involvement
6. High initial WBC (e.g. >100 x 10^9/L)
7. non-Caucasian

Hypogammaglobulinemia is a complication of chronic lymphocytic leukaemia (CLL) that leads to recurrent infections.

CLL is a type of cancer caused by monoclonal proliferation of well-differentiated lymphocytes, typically B cells (99%). Onset of the disease is usually asymptomatic and later constitutes anorexia, weight loss, bleeding, and recurrent infections. Lymphadenopathy is more marked in CLL than in chronic myelogenous leukaemia (CML).

Investigations to diagnose CLL include blood film and immunophenotyping. Smudge cells (also known as smear cells) seen on the blood film point towards CLL. Complications of the disease include hypogammaglobulinemia leading to recurrent infections, autoimmune haemolytic anaemia in 10–15% of the patients, and transformation to high-grade lymphoma (Richter’s transformation).

The most common type of Hodgkin’s lymphoma (HL) is nodular sclerosing.

HL is a malignant proliferation of lymphocytes characterised by the presence of distinctive giant cells known as Reed-Sternberg cells. It has a bimodal age distribution being most common in the third and seventh decades of life.

According to the histological classification, there are four types of HL:

1. Nodular sclerosing: most common (around 70%), more common in women, associated with lacunar cells, good prognosis

2. Mixed cellularity: Around 20%, associated with a large number of Reed-Sternberg cells, good prognosis

3. Lymphocyte-predominant: Around 5%, Reed-Sternberg cells with nuclei surrounded by a clear space found, best prognosis

4. Lymphocyte-depleted: rare, worst prognosis

Monoclonal gammopathy of undetermined significance (MGUS, also known as benign paraproteinemia and monoclonal gammopathy) is a pre-malignant condition not necessarily leading to its malignant form—multiple myeloma. Around 10% of patients eventually develop myeloma over 10 years, with 50% at 15 years. MGUS causes paraproteinemia and is usually asymptomatic. It is not associated with ostealgia or increased risk of infections. It is often mistaken for multiple myeloma, differing from the latter in, no immunosuppression, normal levels of beta-2 microglobulin, and stable lower levels of paraproteinemia.

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

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).

The diagnosis of Hodgkin disease requires the identification of Reed-Sternberg cells in a characteristic cellular background. The normal cell of origin for the Reed-Sternberg cells remains unclear, with the predominance of evidence indicating a B or T lymphocyte.

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.

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

All of the aforementioned listed tumours, except brain tumours, can metastasise to lungs and produce the typical CXR picture consisting of hilar lymphadenopathy with either diffuse multinodular shadows resembling miliary disease or multiple large well-defined masses (canon balls). Occasionally, cavitation or calcification may also be seen.

Most brain tumours, however, do not metastasise. Some, derived form neural elements, do so but in these cases, intraparenchymal metastases generally precede distant haematogenous spread.