Not many people are aware, but sometimes you can experience changes in the shape of your fingers and your nails.
This happens naturally and can include curving of the nails, the nail bed softening, the skin next to the nail bed becoming shiny and the end of your fingers getting larger.
According to Cancer Research, these can all mean early signs of lung cancer and more than 35 percent of people with non small cell lung cancer experience finger clubbing.
Here's how to figure out if you have finger clubbing.
The Diamond Gap test - or the schamroth window test - is an easy, free way you can check to see if you have finger clubbing.
To do the test, you simply need to press your nails together and check whether there is a tiny diamond-shaped window of light between them.
If you don't have the 'diamond gap' then it's possible you could have finger clubbing.
Those who think they might have finger clubbing are advised to speak to their doctor.
On their website, Cancer Research says: "Finger clubbing is unusual. If you have it and are worried, do speak to your doctor."
"They should send you for a chest x-ray to check your heart and lungs."
They added: "Clubbing is thought to be caused by fluid collecting in the soft tissues at the end of the fingers."
"This is caused by more blood flowing to the area than usual. But we don't fully understand why this happens."
"It may be due to the tumour producing particular chemicals or hormones."