#3 Nail or toenail clubbing
When the nail bed softens, the nails curl around the fingertips, resembling an upside-down spoon. Cancer cells release chemicals (such as hormones or proteins) that cause it.
Clubbing of the nails can be caused by a variety of conditions, including lung cancer. Nicotine stains on the fingers is one sign that clubbing is caused by lung cancer, according to physicians.
Early-stage lung cancer finger clubbing is characterized by a soft nail bed, glossy skin, nails that seem more curled than usual if seen from the side, and bigger fingers. Finger clubbing caused by advanced lung cancer may even lead to the development of additional bone regions along the finger joints and wrists.
