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Mediastinal germ cell tumours

Mediastinal germ cell tumours develop in germ cells. These are the cells in the body that develop into sperm and eggs.

Germ cell tumours usually develop in the testicles or ovaries but can grow in other areas of the body, such as the mediastinum (pronounced media-sty-num).

The mediastinum is the area in the centre of the chest, between the lungs. It contains the heart, windpipe (trachea), food pipe (oesophagus), large main blood vessels and the lymph nodes that surround the heart.

About mediastinal germ cell tumours

Germ cell tumours that grow outside the ovary or testicle are very rare. Doctors call them extragonadal germ cell tumours (EGGCT). The mediastinum is the most common place for extragonadal tumours to develop.

Doctors aren’t certain how germ cell tumours develop in the mediastinum. There are some theories about how the cells get outside the testicle and ovary.

These include:

  • the cancer develops from very early cells that became misplaced during our development in the womb
  • the cancer started in the testicle or ovary and spread at a very early stage, but the original cancer has either disappeared or is too small to find

Types

A number of different types of germ cell tumours can develop in the mediastinum. These are much more common in males than females.

They are generally put into 2 main groups:

  • non seminoma germ cell tumours (in females these are called non dysgerminomas) - including teratomas, choriocarcinomas, embryonal carcinomas and yolk sac tumours
  • seminomas (in females these are called dysgerminomas)

Some teratomas can be non cancerous (benign).

Symptoms

Many people with a non cancerous (benign) tumour in the mediastinum don’t have any symptoms. The doctor might spot the tumour on a chest X-ray you had for another reason.

Most people with a cancerous mediastinal tumour have symptoms which might include:

  • shortness of breath
  • pain in the chest
  • a cough
  • raised temperature
  • weight loss
  • night sweats

Diagnosing

Doctors use various tests to diagnose mediastinal germ cell tumours. These might include:

  • a chest X-ray
  • blood tests – germ cell tumours often produce chemicals or hormones (tumour markers) that doctors can measure in the blood
  • a test to look inside the chest (mediastinoscopy)
  • CT scan
  • an ultrasound scan of the ovaries or testicles to check for signs of cancer
  • MRI scan

Treatment

Your treatment depends on what type of mediastinal germ cell tumour you have.

It may include chemotherapy, surgery, radiotherapy or a combination of these treatments. 

You have surgery to remove non cancerous (benign) teratomas. These tumours can be very large. This is often major surgery due to the position of the tumour.

Chemotherapy

Chemotherapy is the most common treatment for non seminoma germ cell tumours. Chemotherapy uses anti cancer (cytotoxic) drugs to destroy cancer cells. 

You usually have a combination of chemotherapy drugs.

The most common combination is BEP. This stands for the chemotherapy drugs bleomycin, etoposide and cisplatin. You may have treatment on a clinical trial, or intensive chemotherapy using different drugs. 

After chemotherapy, your doctor will probably arrange a scan and more blood tests to check how well the treatment has worked. The tumour may shrink away altogether.

Surgery

You might have surgery if there is any sign that the cancer is still there after chemotherapy. 

During the operation, the surgeon removes any cancer left behind. They send this to the laboratory, where a specialist examines it.

The type of surgery depends on where the remaining tumour is and whether it is close to any important body structures such as main blood vessels.

Your surgeon will be able to explain exactly what is involved if you need an operation.

Your doctor might consider further chemotherapy if there is still cancer left behind .

Your treatment depends on the size of the cancer.

Radiotherapy

Radiotherapy uses high energy rays to kill cancer cells.

You usually have radiotherapy if the cancer is small. This can often get rid of the cancer completely. 

Chemotherapy

Chemotherapy uses anti cancer (cytotoxic) drugs to destroy cancer cells. It's the usual treatment for larger cancers. 

You usually have a combination of chemotherapy drugs. The most common type is BEP. This stands for the chemotherapy drugs bleomycin, etoposide and cisplatin. The treatment can get rid of the tumour completely for some people. 

If treatment doesn't get rid of the cancer

Your doctor is likely to suggest that they monitor you if the remaining area is smaller than 3cm. This is to see if the cancer grows again. They might call this observation.

You doctor might monitor you if the remaining cancer is larger than 3cm. Or they might suggest surgery to remove the remaining cancer.

Follow up

After treatment, you will have regular check ups, including tests for any sign of the cancer coming back.

Tests will include chest X-rays, and blood tests to check for any changes in the level of the tumour markers.

Last reviewed: 
12 Jul 2018
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