Oesophageal cancer

Description

Cancer of the oesophagus is a malignant tumour of the passage connecting the mouth to the stomach. The incidence varies in different parts of the world.

Types and known risk factors

There are two distinct types of cancer of the oesophagus:

• Squamous cell carcinoma – from the lining cells of the oesophagus; and
• Adenocarcinoma – from the glands of the oesophagus.

These two have slightly different patterns of incidence and risk factors, but the distinction is academic only, because they cause the same symptoms, and have very similar outcomes.

Squamous cell carcinoma risk factors:

• Alcohol and tobacco abuse
• Diets low in fruits and vegetables
• Exposure to dietary N-nitroso compounds (such as pickles), and some fungi
• Betel nut chewing
• Consuming very hot food and drinks
• Selenium and zinc deficiency
• Underlying oesophageal disease – achalasia, caustic strictures, or previous partial gastrectomy
• Human papilloma virus infection, and
• Other cancers of the oropharynx

Adenocarcinoma risk factors:

• Caucasians more at risk than blacks
• Males eight time more at risk than females
• Barret's metaplasia (a premalignant condition) of the oesophagus
• Smoking
• Obesity
• Helicobacter pylori infection
• Excess acid exposure, for instance in Zollinger-Ellison syndrome
• Previous cholecystectomy – gall bladder removal may increase duodenal reflux of irritant bile, and
• Nitroso compound exposure as for squamous carcinoma

Symptoms

• The predominant symptom is difficulty swallowing, or even pain on swallowing. At first, bulky solids, but later even soft foods or liquids cannot be swallowed properly.
• Coughing spells and vomiting may follow attempts to eat, and result in aspiration pneumonia.
• Persistent heartburn, or chest pain not related to eating patterns is common.
• Vomiting of blood alone or after eating, is frequently found.
• Weight loss and dehydration is due to lack of food and fluids.
• Pressure of the tumour can compress surrounding structures, and may cause, for instance, superior vena caval syndrome.
• Fistula formation – an abnormal connection – between the oesophagus and trachea.
• Distant spread causes symptoms according to the organ affected, for instance liver or lung.

Diagnosis, tests and spread

The symptoms described by the patient usually suggest the diagnosis, but tests must be done to see if there are other, treatable causes of the symptoms:

• Barium studies – these give a good outline of the lumen (the inside opening) of the oesophagus, and show narrowing or obstruction very well, but do not show the cause.
• Endoscopic biopsy combined with brush cytology gives a 100% accurate diagnosis. Here small samples of tissue are taken for testing, by means of biopsy and by brushing the surface of the tumour.
• Endoscopic ultrasound gives extremely accurate pictures of the staging (spread) of the tumour. However, if the tumour significantly narrows the oesophagus, the scope cannot pass through it, and this limits its usefulness.
• PET, CT or MRI scans are used to show distant spread.

Squamous cancers tend to spread within the chest, to the glands and the lungs. Adenocarcinomas spread more to distant glands, liver, bone, peritoneum and adrenal glands.

Treatment

Surgery

Tumour confined to the oesophagus is found in only 20% to 30% of patients. For these lucky few, oesophagectomy (total removal of the oesophagus) may be curative. This is major surgery, with many possible complications, but is the only real chance of a cure. The excised oesophagus can be replaced with a portion of the patient's own colon.

Chemotherapy

This may be used before, after, instead of surgery or in combination (chemo radiation), depending on the extent of spread and the type of cancer. Chemotherapy - is the use of drugs to kill cancer cells. It may be given alone or together with radiation therapy – either before or following surgery in early cases, or to relieve symptoms of the disease if the cancer cannot be removed. The doctor may use one drug or a combination of drugs.

Chemotherapy is usually given in cycles: a treatment period followed by a recovery period, then another treatment period, and so on. Most anticancer drugs are given by injection into a vein (IV); some are given by mouth. Chemotherapy is a systemic therapy – meaning that the drugs flow through the body in the bloodstream. Usually a person receives chemotherapy as an outpatient (at the hospital, or at the doctor’s office). However, a short hospital stay may be needed, depending on the person's general health and on which drugs are used.

The side effects of chemotherapy depend on the specific drugs and doses used. They also vary greatly from person to person. Before starting chemotherapy your doctor will explain to you fully, the side effects that you can expect. Most chemotherapy drugs affect all rapidly dividing cells in the body. That means that the normal cells most commonly affected are the bone marrow cells, the hair root cells, and the cells lining the digestive tract. For this reason, the blood count must be monitored before every cycle of chemotherapy. The number of red blood cells, white blood cells and platelets is monitored, as drops in any of these counts can lead to problems. Many, but not all, of the chemotherapy drugs may cause the hair to fall out. Also, during the first week or so after the chemotherapy, certain drugs may cause ulcers in the mouth, nausea and vomiting, or diarrhoea. The patient will be warned if this is to be expected with the proposed treatment.

Radiotherapy

In patients with severe symptoms, a course of radiotherapy can be given before surgery. It can also be used after surgery if indicated and improves local recurrence rates.

Radiation therapy - (also called radiotherapy) is the use of high-energy rays to damage cancer cells and stop them from growing and dividing. Like surgery, radiation therapy is local therapy; the radiation can affect cancer cells only in the treated area.

The patient lies on a bed and a machine, similar to an X-ray machine, is used to aim the radiation at the area defined by the radiation oncologist.

Doctors may use radiation therapy before surgery to shrink a tumour so that it is easier to remove, or after surgery to destroy cancer cells that may remain in the area. Radiation may also be given alone or with chemotherapy to relieve pain or digestive problems if the tumour cannot be removed. In most cases, patients receive radiation treatment as an outpatient in a hospital or clinic. The treatments are short – usually lasting only minutes – but must be given daily, four or five times a week.

The course may be as short as three weeks or last for several weeks, depending on what is being treated.

Side effects of radiation depend on the dose given and the area treated. Patients receiving radiation tend to get very tired, especially towards the end of the treatment.

The skin in the treatment area may become itchy and red. The patient will be asked not to wash or rub this area during treatment or to use any creams or lotions without discussing this with the doctor first, as they may exacerbate the problem. The skin will heal after radiation, but there may be permanent “bronzing” of this area. There will also be hair loss (in the treated area only).

Radiation over the abdomen can also cause nausea and vomiting as well as diarrhoea and pain on swallowing. Medication can be given to combat these problems, and they usually disappear at the end of the treatment.

Stents

A stent (expandable mesh tube) may be inserted into an area of extreme narrowing, to keep the oesophagus open and permit saliva, food and drink to be swallowed. This is done for inoperable patients who may be literally starving to death.

Outcome

The outcome of oesophageal cancer is poor. Even with early surgery, only 25% survive five years. For those who are not candidates for surgery, the prognosis is even worse.

Dr A G Hall, Health24, February 2008

Dr C Jacobs April 2008