Basal cell and squamous cell carcinoma diagnosis and staging


Because no two people develop skin cancer in the same way, we offer a wide array of resources for proper evaluation of your situation—and we use that information to create a personalized plan to fit your specific needs. Once a cancer has been diagnosed, our specialists need to know where it may have spread. This is the “stage” of the cancer. The lower the number, the less it has spread. Knowing the stage allows us to determine the best possible treatment plan for you.

We may use any combination of these tests and procedures to diagnose and stage skin cancer:

Biopsy. Removes all or part of the abnormal-looking skin growth for viewing under a microscope by an expert skin pathologist to check for signs of cancer.

CT scan (computed tomography). Uses a type of X-ray to create detailed, highly accurate, cross-sectional images of the body

Dermoscopy. Uses a drop of mineral oil on the lesion to reduce light reflection, make the skin more translucent, and assist in viewing skin lesions to accurately distinguish between suspicious moles and other pigmented lesions.

Epiluminescence microscopy. Allows viewing of a lesion down to the dermo-epidermal junction—the areas where melanomas usually develop—that isn’t visible to the naked eye.

Excisional biopsy. Uses a scalpel to remove the entire growth.

Punch biopsy. Uses a special instrument called a punch to remove a circle of tissue from the abnormal-looking growth.

Skin examination. Uses a visual check of the skin for bumps or spots that look abnormal in color, size, shape, or texture.


To stage basal and squamous cell skin cancer, UCHealth follows the American Joint Commission on Cancer (AJCC) TNM system.

The most recent version, effective as of 2018, applies only to squamous and basal cell skin cancers of the head and neck area (lip, ear, face, scalp and neck). The stage is based on 3 key pieces of information:

  1. The size of the tumor (T) and if it has grown deeper into nearby structures or tissues, such as a bone.
  2. If the cancer has spread to nearby lymph nodes (N).
  3. If the cancer has spread (metastasized) to distant parts of the body (M).

Numbers or letters after T, N, and M provide more details about each of these factors. Higher numbers mean the cancer is more advanced.

Once a person’s T, N, and M categories have been determined, this information is combined in a process called stage grouping to assign an overall stage. The earliest stage of skin cancer is stage 0 (also called carcinoma in situ, or CIS). The other stages range from I (1) through IV (4). As a rule, the lower the number, the less the cancer has spread. A higher number, such as stage IV, means cancer has spread more.

If your skin cancer is in the head and neck area, talk to your doctor about your specific stage. Cancer staging can be complex, so ask your doctor to explain it to you in a way you understand.

Source: American Cancer Society

Basal cell and squamous cell carcinomas: learn more