Testicular cancer most commonly affects young and middle-aged men.
Over 2,200 men are diagnosed with it in the UK each year.
It occurs when normal, healthy cells, which are carefully regulated by the body, begin to reproduce uncontrollably within the testicles.
According to the UK’s male cancer charity Orchid, around 47% of men diagnosed with testicular cancer will be under the age of 35.
If caught at an early stage, men can expect a high cure rate with 98% of men remaining disease free at one year. If caught at any stage, 98% of men will be alive 10 years after treatment
Considering that when diagnosed, testicular cancer can be treated effectively, it seems critical that everything is done to check for the disease.
Rebecca Porta, chief executive of Orchid said: "Most of them don’t know this is something they need to look at, whereas young girls are very aware about breast cancer. Testicular cancer is the biggest cancer for young men aged between 15–35."
Are some people more prone to it than others? Like a lot of other cancers, a lot of the reasons are unknown but it could be that genetics plays a role. If your brother or father had it, there is a possibility that you may get it too.
"We know that Caucasian men are more likely to get it," says Rebecca, "and there are other possible reasons - if you've had a history of mumps or a severe blow to the testicles. But there's nothing conclusive."
Undescended testicles, says the NHS, is the most significant factor in whether a person develops testicular cancer later in life. For some children, they say, the testicles fail to descend - it is called cryptorchidism.
"Surgery is usually required to move the testicles down. If you have had surgery to move your testicles down into your scrotum, your risk of developing testicular cancer may be increased.
"One study found if surgery is performed before the child is 13 years of age, their risk of later developing testicular cancer is approximately double that of the rest of the population. However, if the operation is carried out after the boy is 13 years of age, the risk of developing testicular cancer is five times greater than that of the rest of the population."
The good news is that testicular cancer is labelled as one of the most 'treatable' types of cancer.
Here are the symptoms you should be looking out for:
- A dull ache or sharp pain in your testicles or scrotum, which may come and go
- A feeling of heaviness in your scrotum
- A dull ache in your lower abdomen (stomach area)
- A sudden collection of fluid in your scrotum (hydrocele)
- A general feeling of being unwell
- Dragging sensation in 29% of cases
- Breast swelling or tenderness (called gynaecomastia). This is rare but may be caused by hormones, which are produced by some types of testicular cancer
- Enlarged lymph nodes in the back, which have enlarged due to spread of cancer
If you notice a lump in your testicles - don't panic. You should see your GP but bear in mind that only 4% of testicular lumps tend to be cancerous.
So how do you check your testicles?
Orchid's spokesperson advises: "Get to know your balls. Every time you are in the bath or shower examine each testicle - that way you’ll spot any changes.
"Also, roll each testicle between your thumb and forefinger to check that the surface is free of lumps and bumps - don't squeeze."
If you are diagnosed with testicular cancer, what does the treatment involve?
This depends on the type of cancer you have - whether it is a seminoma or a non-seminoma cancer, and also at what stage you have been diagnosed. The first course of treatment will include removing the testicle which contains the tumour - called an orchidectomy - this will also be followed by a course of chemotherapy or radiotherapy.
This may sound extreme - but you will still be able to have children with one testicle, and the survival rate of removing the testicle is very high.
Compared to the 1960s, when the survival rate was 6%, now you have a very good chance of beating the disease thanks to developments in cancer drugs.
The Institute of Cancer Research says: "Carboplatin has become a standard treatment for a common sub-type of testicular cancer called seminoma. For seminoma patients, a single dose of this drug has proved to be as effective at treating testicular cancer as two to three weeks of radiotherapy, with the added benefit of fewer side-effects. It also allows surgeons to remove just the affected part of a testicle, rather than the whole organ."