SkinCancerNet, website of the American Academy of Dermatology. When skin cancer is diagnosed, the first thing the dermatologist must find out is how far it has spread. This is staging. This website page explains the process for staging. With basal cell or squamous cell carcinoma, which do not spread as fast, frequently only the biopsy is needed to stage the cancer. With melanoma, which can spread rapidly, an additional special form of biopsy may be needed to check the lymph nodes, and various imaging tests may be used to check for spread to other organs.