Oncology - Oncological emergencies and metastatic disease

Question 1

How common is spinal cord compression?

Answer 1

Spinal cord compression complicates 5% of cancers and is most common in myeloma, prostate, breast and lung cancers that involve bone. Cord compression often results from posterior extension of a vertebral body mass, but intrathecal spinal cord metastases can cause similar signs and symptoms.

Question 2

What is the earliest feature of spinal cord compression?

Answer 2

Back pain is the earliest sign, particularly on coughing and lying flat. Subsequently, sensory changes develop in dermatomes below the level of compression and motor weakness distal to the block occurs. Finally sphincter disturbance, causing urinary retention and bowel incontinence is observed.

Physical examination reveals findings consistent with an upper motor neurone lesion, but lower motor neurone signs may predominate early or in cases of nerve root compression.

Question 3

What are the features of spinal cord lesions?

Answer 3

Weakness - symmetrical and profound (spastic)
Reflexes - increased (or absent) knee and ankle with extensor plantars
Sensory loss - symmetrical, sensory level
Sphincters - late loss
Progression - rapid

Question 4

What are the features of a conus medullaris lesion?

Answer 4

Involvement of the lumbar spine may cause conus medullaris or cauda equina syndrome.
Weakness - symmetrical and variable
Reflexes - increased knee, decreased ankle, upgoing plantar
Sensory loss - symmetrical, saddle distribution
Sphincters - early loss
Progression - variable

Question 5

Features of cauda equina syndrome?

Answer 5

Weakness - asymmetrical, may be mild
Reflexes - decreased knee and ankle, normal plantars
Sensory loss - asymmetrical, radicular pattern
Sphincters - often spared
Progression - variable

Question 6

How should spinal cord compression be managed?

Answer 6

Cord compression is a medical emergency and should be treated with analgesia and high dose steroids:
- confirm diagnosis with MRI
- administer high dose steroids
Dexamethasone 16 mg IV stat
Dexamethasone 8 mg BD PO
- ensure adequate analgesia
- refer for surgical decompression or urgent radiotherapy

Neurosurgical treatment produces better outcomes compared with radiotherapy for most cases. Radiotherapy is used for remaining patients and selected tumour types where the cancer is likely to be radiosensitive.

Question 7

What is superior vena cava obstruction?

Answer 7

SVCO is a common complication of cancer that can occur through extrinsic compression or intravascular blockage. The most common causes of extrinsic compression are lung cancer, lymphoma and metastatic tumours. Patients with cancer can also develop SVCO due to intravascular blockage in association with central catheter or thrombophilia secondary to the tumour.

Question 8

What are the clinical features of SVCO?

Answer 8

The typical presentation is with oedema in the arms and face, distended neck and arm veins and dusky skin colouration over the chest, arms and face. Dyspnoea is the most common symptom. Collaterals may develop over a period of weeks and the flow of blood in collaterals helps to confirm the diagnosis.

Headache secondary to cerebral oedema arising from the backflow pressure may also occur and tends to be aggravated by bending forward, stooping or lying down. The severity of symptoms is related to the rate of obstruction and the development of venous collaterals

Question 9

How is SVCO investigated?

Answer 9

The investigation of choice is a CT thorax, since it can confirm the diagnosis and distinguish between intra - and extravascular causes. A biopsy should be obtained when the tumour type is unknown because tumour type has a major influence on treatment. CT of the brain may be indicated if cerebral oedema is suspected.

Question 10

How is SVCO treated?

Answer 10

Tumours that are sensitive to chemotherapy such as germ cell tumours and lymphoma can be treated with chemotherapy alone, but for most tumours mediastinal radiotherapy is needed. This relieves symptoms within 2 weeks in 50-90% of patients.

In most centres, stenting is now favoured to radiotherapy, as it produces rapid results and can be repeated. This technique is particularly useful when dealing with tumours that are chemo resistant, such as non small cell lung carcinoma, or carcinoma of unknown primary.

Question 11

What cancers are most associated with hypercalcaemia?

Answer 11

Incidence of malignant hypercalcaemia is highest in breast, intermediate and non small cell lung cancer. It is uncommon in GI, prostate and small cell.

It is most commonly caused by over production of PTHrP, which binds to the PTH receptor and raises serum calcium by stimulating osteoclastic bone resorption and increasing renal tubular reabsorption of calcium.

Question 12

What are the clinical features of hypercalcaemia?

Answer 12

Symptoms of hypercalcaemia are often non specific, and may mimic those of the underlying malignancy. They include drowsiness, nausea, confusion, vomiting, polydipsia, polyuria and dehydration.

Question 13

How should suspected cases of hypercalcaemia be investigated?

Answer 13

The diagnosis is made by measuring serum calcium and adjusting for albumin (corrected calcium). It is especially important to correct for albumin in cancer because hypoalbuminaemia is common, and total calcium values underestimate the level of ionised calcium.

Question 14

How is malignant hypercalcaemia managed?

Answer 14

Patients should be treated initially with intravenous 0.9% saline to improve renal function and increase urinary calcium excretion. This alone often results in clinical improvement.

IV bisphosphonates (Zalindronic acid or pamidronate) should be given to inhibit bone resorption. Calcitonin acts rapidly to increase calcium excretion and to reduce bone resorption and can be combined with fluid and bisphosphonate therapy for the first 24-48 hours in patients with life threatening hypercalcaemia.

Bisphosphonates will usually reduce the serum calcium levels to normal within 5 days, but if not treatment can be repeated. Hypercalcaemia is frequently a sign of tumour progression and the patient requires further investigation.

Question 15

What tumours commonly metastasise to the brain?

Answer 15

Lung (most common)
Breast
Melanoma
Bowel

Brain mets occur in 10-30% of adults and 6-10% of children with cancer. Most affect brain parenchyma but can also affect cranial nerves, blood vessels and other structures.

Tumour type influences prognosis, breast metastasis have a more favourable prognosis compared to colorectal carcinoma which is much poorer.

Question 16

What are the common clinical features of brain metastases?

Answer 16

Presentation is with headaches, focal neurology, cognitive dysfunction, seizures, and papilloedema (in order of most common to least).

Question 17

How are brain metastases managed?

Answer 17

The diagnosis is confirmed using CT or contrast enhanced MRI. Treatment options include high dose steroids (dexamethasone 4 mg 4 times daily) for tumour associated oedema, anticonvulsants for seizures, whole brain radiotherapy, and chemotherapy. Surgery may be considered for single sites of disease and can be curative; stereotactic radiotherapy may also be considered for solitary site involvement where surgery is not possible.

Question 18

What cancers commonly metastasise to the lungs? How should they be investigated?

Answer 18

These are common in breast, colon, and tumours of the head and neck. The presentation is usually with a lesion on CXR or CT. Solitary lesions require investigation, as a single metastases can be difficult to distinguish from a primary lung tumour. Patients with two or more lung nodules can be assumed to have metastases.

Question 19

How are lung metastases treated?

Answer 19

The approach to treatment depends on the extent of disease in the lung and elsewhere. For solitary lesions, surgery should be considered with a generous wedge resection. Radiotherapy and chemotherapy or endocrine therapy can be used as a systemic treatment and is dependent on the underlying primary cancer diagnosis.

Question 20

What cancers metastasise to the liver? How do they present?

Answer 20

Metastatic cancer of the liver can represent the sole or life limiting component of disease for many with colorectal cancer, ocular melanoma, neuro-endocrine tumours, and less commonly, other tumours. The most common clinical presentations are with right upper quadrant pain due to stretching of the liver capsules, jaundice, deranged LFTs or an abnormality on imaging.

Question 21

How are liver metastases managed?

Answer 21

In selected cases, resection of the metastasis can be contemplated. In colorectal cancer, successful resection of a metastases improves 5 year survival from 3% to 30-40%. Other techniques such as radiofrequency ablation can also be used provided the number and size of the metastases remains small. Systemic chemotherapy is also an option.

Question 22

How common are bone metastases and what cancers are associated with them?

Answer 22

Bone is the third most common organ involved by metastasis, after lung and liver. Bone metastases are a major clinical problem in patients with myeloma and breast or prostate cancers, but other tumours that com- monly metastasise to bone include those of the kidney and thyroid.

Question 23

What are the clinical features of bone metastases?

Answer 23

The main presentations are with pain, pathological frac- tures and spinal cord compression. The pain tends to be progressive and worst at night, and may be partially relieved by activity, but subsequently becomes more constant in nature and is exacerbated by move- ment. Most pathological fractures occur in metastatic breast cancer (53%); other tumour types associated with fracture include the kidney (11%), lung (8%), thyroid (5%), lymphoma (5%) and prostate (3%).

Question 24

How should bone metastases be investigated?

Answer 24

The most sensitive way of detecting bone metastases is by isotope bone scan. This can have false-positive results in healing bone, particularly as a flare response follow- ing treatment and false-negative results occur in multi- ple myeloma due to suppression of osteoblast activity. Therefore plain X-ray films are preferred for any sites of bone pain, as lytic lesions may not be detected by a bone scan. In patients with a single lesion, it is especially important to perform a biopsy to obtain a tissue diagno- sis, since primary bone tumours may look very similar to metastases on X-ray.

Question 25

How are bony metastases treated?

Answer 25

Bony metastases are sensitive to radiotherapy, NSAIDs and bisphosphonates. Surgical intervention may be warranted where there is evidence of skeletal instability (e.g. anterior or posterior spinal column fracture) or an impending fracture (e.g. large lytic lesion on a weight-bearing bone with more than 50% cortical involvement).

Question 26

What cancers are associated with malignant pleural effusion? How do they present?

Answer 26

This is a common complication of cancer and 40% of all pleural effusions are due to malignancy. The most common causes are lung and breast cancers, and the presence of an effusion indicates advanced and incurable disease. The presentation may be with dyspnoea, cough or chest discomfort, which can be dull or pleuritic in nature.

Question 27

How is malignant pleural effusion investigated?

Answer 27

Pleural aspirate is the key investigation and may show the presence of malignant cells. Malignant effusions are commonly blood-stained and are exudates with a raised fluid to serum lactate dehydrogenase (LDH) ratio (> 0.6) and a raised fluid to serum protein ratio (> 0.5). Treat- ment should focus on palliation of symptoms and be tailored to the patient’s physical condition and progno- sis. Aspiration alone may be an appropriate treatment in frail patients with a limited life expectancy.

Those who present with malignant pleural effu- sion as the initial manifestation of breast cancer, small cell lung cancer, germ cell tumours or lymphoma should have the fluid aspirated and should be given systemic chemotherapy to try to treat disease in the pleural space. Treatment options for patients with recurrent pleural effusion include pleurodesis, pleurectomy and pleuroperitoneal shunt.