Germ cell cancer

Yuvraj Singh recently announced that he is being treated for germ cell cancer. What exactly is that?

Germ cell cancer - yuvraj singh

Yuvraj Singh, who's getting chemotherapy, recently tweeted a picture of himself

Before launching a discussion of germ cell cancer, yes the same one that ace cricketer Yuvraj Singh has been diagnosed with, let’s talk about what a germ cell actually is and the anatomy of the chest which is relevant to this cancer.

What is a germ cell?

A germ cell is a primitive cell in the embryo which develops into sperm cells in men and egg cells in women. Hence, in most cases, germ cell tumours originate in the testes or the ovaries. However in rare cases, they can grow in other parts of the body like the brain, stomach or mediastinum*. Hence, these tumours are given the name extra gonadal tumours. The mediastinum is the commonest site for the development of an extra gonadal tumour.

*The mediastinum is the anatomical term for the area in the centre of the chest between the two lungs. It houses the heart, major blood vessels, the food pipe and the wind pipe.

Causes of germ cell cancer

About 10% of mediastinal tumours are due to germ cells and 85% of these are benign.

This type of cancer is common in young adults between the second and fourth decades and equally distributed between the sexes.

The cause is mostly genetic. During the embryo stage, some germ cells migrate to areas like the brain or mediastinum and remain there. These may later form a malignant tumour.

It may also be associated with Klinefelter’s syndrome which has a genetic origin.

Classification of germ cell cancer

Germ cell tumours can be benign or malignant. This includes tumours in the mediastinum.

Benign ones are teratomas and teratodermoids.

Malignant are seminomas and non-seminomatous germ cell tumours

Symptoms and signs of germ cell cancer

Benign tumours rarely produce symptoms, if any. Infection occurs only in very rare cases.

Malignant germ cell cancers may show symptoms like:

  • Chest pain
  • Shortness of breath
  • Cough
  • Fever
  • Loss of weight
  • Pressure on lungs, chest wall and other structures in close proximity
  • Sometimes, gynaecomastia (enlargement of male breasts) is a feature

Diagnosis of germ cell cancer

The patient may be pale and may complain of fever or unexplained weight loss over months or years. In case of respiratory symptoms like cough, breathlessness or chest pain the physician may advise an X-ray. Chest X-ray done as a part of a routine check up may show a mass in the mediastinum.

Investigations

Routine blood, urine and stool tests are mandatory.

CBC may show raised ESR and increase in lymphocytes. Specific blood tests include Human Chorionic Gonadotropin (HCG) and alpha fetoprotein which are clues to this cancer. These are almost always elevated in non-seminomatous germ cell tumours.

Chest X-ray done as a part of a routine check up may show a mass in the mediastinum.

CT scan is helpful to determine the type of tumour, its density and where it has spread.

MRI is of little value in germ cell tumours. Nuclear imaging using iodine as the dye is helpful to diagnose a thyroid mass and hence the tumour can be differentiated from a thyroid mass. Angiography is needed to differentiate a mediastinal tumour from a blood vessel malformation.

Sometimes a small surgery called open biopsy is required to find out what kind of tumour it is. In this procedure a small part of the tumour is removed and sent to the laboratory for analysis.

Staging:

According to the size of the tumour and depending on where it has spread (near or far away) the tumour is divided into four stages. According to the stage, the treatment protocol is established.

Treatment of germ cell cancer

Mediastinal tumours are curable even in late stages. For these tumours, radiation can be used but due to the proximity to the heart it is dangerous. Combination therapy using chemotherapy, surgery and radiation may be prescribed.

Surgery is the method of choice to treat benign germ cell tumours in the lungs. However for malignant tumours, surgery is indicated to remove a residual mass after chemotherapy is over.

Under chemotherapy, drugs normally used are bleomycin, ciplatin and etoposide.

Written by Dr Nisreen Nakhoda, General Physician

Photograph courtesy Yuvraj Singh’s twitter feed