Germ-cell tumours

28 April 2011

Germ cells are the cells which develop into sperm and eggs.

Germ cell tumours (GCT) are a diverse group of tumours. They can occur in different parts of the body and there are several distinct sub-types, including yolk-sac tumours, germinomas, embryonal carcinomas and teratomas. These may be malignant or benign.

In adults and adolescents, GCT most commonly develop within the ovaries or testes. These are called gonadal germ cell tumours.

Childhood GCT, however, predominantly arise outside of the gonads.

As a baby develops in the womb the germ cells usually move to the ovaries or testes. Occasionally, however, they fail to migrate to their proper location and settle in other parts of the body, where they can develop into tumours. These are called extragonadal germ cell tumours. The most common places for these tumours to occur are at the bottom of the spine (sacrococcygeal), the brain, chest and abdomen.

Incidence

Germ cell tumours are rare, accounting for around 3 per cent of all childhood cancer registrations. This represents 50 children a year in Britain.

Germ cell tumours have very different age distributions in boys and girls: in boys, incidence peaks very early at around 2-3 years of age; in girls, incidence is low until age 6 or 7 when it begins to increase up to age 15.

Causes

The cause of germ cell tumours is not known.

Survival

The overall survival rate for children diagnosed with GCT is 92 per cent.

The gonadal tumours have an even better prognosis – 99 per cent for gonadal yolk sac tumours, 96 per cent for gonadal germ cell tumours.

Diagnosis and treatment

The symptoms depend on where the tumour develops, but usually a lump appears that can either be felt or leads to other problems.

A variety of tests and investigations may be needed to diagnose a germ cell tumour.

A biopsy is likely to be taken, this will help to determine the precise type of tumour and whether it is malignant or benign. A CT or MRI scan will enable doctors to determine the exact position of the tumour. Chest x-rays may be taken to check whether the cancer has spread to the lungs.

Germ cell tumours often produce proteins that can be measured in the blood. These proteins are known as tumour markers. The levels of these proteins will be checked when the tumour is diagnosed, and will be monitored during and after treatment. Sometimes the presence of these markers is enough to diagnose a GCT and a biopsy is not needed.

The principal treatment for GCT is surgery, except where the tumour is in the central nervous system. If the tumour is benign or, in the case of malignant tumours, if it is localised and has not spread, then surgery alone may be sufficient.

In cases where the tumour has spread, or if it cannot be easily or completely removed, chemotherapy will be given before and after surgery.

Surgery may involve removal of the testis or ovary if this is where the tumour first developed.

Side effects of treatment

Treatment often causes side effects and these will be discussed with you before treatment starts.

The possible side effects of chemotherapy depend upon the drugs used but may include nausea and vomiting, hair loss, reduced resistance to infection, bruising and bleeding, tiredness and diarrhoea.

These problems are all temporary and can be minimised with good supportive care.

Read more: Side effects of treatment

Late effects of treatment

A small number of children treated for germ cell tumours may develop long-term problems as a result of the treatment they receive. These include problems with kidney function, lung function and hearing.

Removal of a single ovary or testis should not affect a child’s future ability to have children.

Read more: Long-term and late effects of treatment

References:
Cancer in Children: Clinical Management (5th edition). Eds: P A Voute, Ann Barrett, Michael C G Stevens and Hubert N Caron. Oxford University Press, 2005.
Childhood Cancer in Britain: incidence, survival, mortality. Ed by Charles Stiller. Oxford University Press, 2007.
Macmillan Cancer Support factsheet - Germ cell tumours in children (2010).

Related Topics types of childhood cancer, Germ-cell tumours