Treatment options
Treatment is aimed at managing the obstruction as well as the underlying diagnosis. It will also be influenced by the severity of symptoms and the type of tumour. Immediate management includes assessment of the patient’s airway, breathing and circulation. It is advisable to sit the patient upright and administer oxygen if indicated. Most patients are prescribed dexamethasone 8mg twice a day, together with a proton pump inhibitor for gastric protection, although there are no published studies to show the effectiveness of steroids in this situation.

If there is a suspicion of a lymphoma, steroids should be avoided if possible until a biopsy has been performed. This is because lymphomas can be very sensitive to steroids and the chance of obtaining a tissue diagnosis may be compromised.


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Stenting
Stenting for SVCO is minimally invasive and involves inserting a catheter into a large vein, usually in the groin, and passing it into the narrowed area under radiological guidance. The stent is placed to bridge the narrowed area and relieve the obstruction.

There is evidence that suggests about 95 per cent of patients obtain relief of their symptoms after stenting. The response is more rapid than that seen with radiotherapy or chemotherapy, symptoms usually resolving within 48 hours of stent insertion. It is a safe procedure when carried out by a trained operator. The risks are rare, but include perforation or rupture of the vena cava, stent migration, and embolisation. These risks are increased if anticoagulation is used. Patients may experience transient chest pain following the procedure and occasionally require blood transfusion.2

Stenting to relieve obstruction should be considered a first-line option for patients with non-small cell lung cancer. Radiotherapy should then be considered to treat the underlying disease. In patients with small cell lung cancer who are able to cope with chemotherapy, this is usually the most appropriate first-line treatment. Stenting should be considered if patients with small cell lung cancer develop relapsed SVCO or fail to respond to first-line treatment.

In patients with intrinsic compression secondary to thrombosis, anticoagulation should be used. If the thrombosis is associated with central venous instrumentation, the line should be removed. These patients may also require stenting, although this is associated with a higher rate of complications owing to the anticoagulants.

Radiotherapy
If it is not possible to stent patients with non-small cell lung cancer, radiotherapy can be considered as first-line treatment. The radiotherapy treatment field aims to cover the site of obstruction and as much of the primary tumour as possible. Large radiation fields are associated with increased toxicity and this can limit the volume of tissue that can be treated.

Radiotherapy in patients with lung cancer is usually palliative, so the dose and duration of treatment depend on the patient’s fitness and the extent of the disease. Treatment is usually given daily over one or two weeks, but shortened treatment regimens can be used in frail elderly patients.

Common radiotherapy side-effects include sore skin, cough, tiredness, and dysphagia. Relief of symptoms should begin about 72 hours later, but may take up to 14 days.

Systemic chemotherapy
In patients with small cell lung cancer, lymphoma, or testicular cancer, chemotherapy is often the most appropriate option for first-line treatment, provided that patients have adequate performance status and are fit for chemotherapy. These tumour types are very chemosensitive and most of these patients respond rapidly. In patients with non-small cell lung cancer, the response rates to chemotherapy are not as good. In these circumstances, chemotherapy is not often used as an immediate treatment, although it may be used later in the course of treatment or in combination with radiotherapy.

Outcomes
In trials involving patients with small cell lung cancer, it has been shown that 77 per cent of patients obtained relief of symptoms with chemotherapy or radiotherapy. Seventeen per cent of these patients subsequently had a recurrence of SVCO. In non-small cell lung cancer, 60 per cent had relief with chemotherapy or radiotherapy and 19 per cent had a recurrence. Stenting relieved obstruction in 95 per cent of cases and 11 per cent had a recurrence of SVCO; most of these were successfully re-stented.3 The prognosis is determined by the underlying disease and its extent, but is generally poor in patients with lung cancer, with survival usually being only six to nine months.

Dr Alice Dewdney is a clinical oncology specialist registrar at University College Hospital, London, and Dr Julian Singer is consultant oncologist at the North Middlesex Hospital. Competing interests: None declared 

References
1. Wilson LD, Detterbeck FC, Yahalom J. Superior vena cava syndrome with malignant causes. N Engl J Med 2007;356:1862-8.
2. NICE. Guidance on stent placement for vena caval obstruction. IPG079. NICE, London, July 2004.
3. Rowell NP, Gleeson FV. Steroids, radiotherapy, chemotherapy and stents for superior vena caval obstruction in carcinoma of the bronchus. Cochrane Database Syst Rev 2001, Issue 4. Art No: CD001316. DOI: 10.1002/14651858.CD001316

Originally published in the March 2009 edition of MIMS Oncology & Palliative Care.