After the initial diagnosis, the doctor will stage the cancer. This determination of severity is based on the doctor's clinical findings as well as results from testing that may have been done, such as biopsy, sentinel node biopsy, bloodwork, x-ray, and MRI or CT scans. Knowing the stage of progression of the cancer helps the doctor to determine appropriate treatment.
Stages of skin cancer range from Stage 0 being least invasive to Stage 4, which is the most invasive. Staging is done differently for melanoma than for non-melanoma skin cancers, so they will be discussed separately.
Stages of Non-Melanoma Skin Cancers
- Stage 0: Abnormal cells are found. These cells have the potential to become cancerous. This stage is sometimes called carcinoma in situ.
- Stage I: Cancerous cells are present. The cancerous lesion is 2 cm. in diameter or smaller.
- Stage II: The cancerous lesion is greater than 2 cm. in diameter, but has not spread beyond the skin.
- Stage III: The cancer has spread to adjoining structures such as cartilage, muscle, or bone. Regional lymph nodes may also be involved.
- Stage IV: Cancer has spread to other, more distant areas of the body, possibly involving organs such as the lungs, liver, and/or the brain.
Stages of Melanoma
- Stage 0: Abnormal melanocytes are present. These cells have the potential to become melanoma. This stage is sometimes called melanoma in situ.
- Stage I: Cancerous cells are present. Cancerous lesion is less than 2 millimeters in thickness.
- Stage II: Cancerous lesion is between 2 mm. and 4 mm. in thickness. Cancerous cells are still confined to the skin.
- Stage III: The disease has spread beyond the skin. Lymph node involvement has occurred.
- Stage IV: Cancer has spread beyond the regional lymph nodes. Distant metastasis to organs such as liver, lungs and brain has occurred.
Treatment
For Stage I or II skin cancer of any type, surgery alone is very often the only treatment necessary for a cure. At Stage III or IV, however, adjuvant therapy is usually held as an option.
Five-Year Survival Rates
Basal cell carcinoma rarely spreads beyond stage II, so its 5 year survival rate nears 100%. Squamous cell carcinoma also has a very high 5-year survival rate, at approximately 96% when diagnosed at Stage I or II. That rate drops to 50% or less when diagosed at Stage III or IV, however.
Melanoma 5-year survival rates are approximately as follows:
- Stage 0-- nearly 100%
- Stage I and Stage II-- 98%
- Stage III-- 60%
- Stage IV-- 16%
The sudden drop in survival rates for more advanced skin cancers highlights the urgency of early detection of skin cancer. An advantage in early detection of skin cancer is that it's right on the outside for you to see. It pays to pay attention!
Suggested Reading:
Cancer Shock: Your Feelings Matter
Sources:
National Cancer Institute, Cancer Topics
