Stage 0 (in situ)
In Stage 0 melanoma, the malignant tumor is still confined to the upper layer of the skin—the epidermis—which means the cancer cells are only in the outer layer of the skin and have not grown into the second layer of skin, called the dermis. Stage 0 melanoma is not considered invasive melanoma; the other stages (I, II, III, and IV) are invasive. In Stage 0 melanoma, there is no evidence the cancer has spread to the lymph nodes or to distant sites (metastasis). Stage 0 is local melanoma, meaning it has not spread beyond the primary tumor. Another term for Stage 0 melanoma is in situ, which means “in place” in Latin.
Tis (tumor in situ)
- The tumor is limited to the epidermis
- There is no invasion of surrounding tissues, lymph nodes, or distant sites
- Risk: Very low
Characteristics of Stage 0 Melanoma
Stage 0 melanoma is a tumor limited to the epidermis. There are no subgroups for Stage 0 melanoma. In the TNM system (which informs the stage), it’s described as TisN0M0:
- Tis: means Tumor in situ; cancer cells are found only in the outer layer of skin (the epidermis), not the second layer of skin (the dermis)
- N0: means melanoma has not spread to the lymph nodes
- M0: means melanoma has not spread to distant sites (metastasized)
Risk: Patients with Stage 0 melanoma are considered at very low risk for local recurrence or for regional and distant metastases.
Treatment For Stage 0 Melanoma
The standard treatment for Stage 0 melanoma (in situ) is surgery.
The purpose of the surgery is to remove any cancer remaining after the biopsy. This procedure is called a wide local excision. The surgeon removes any remaining tumor from the biopsy site, the surgical margin (a surrounding area of normal-appearing skin), and the underlying subcutaneous tissue, to make certain the whole tumor has been removed. This procedure may be done in a doctor’s office under local anesthetic. The width of the margin taken depends upon the thickness of the primary tumor. The surgical margin for in situ melanoma is 0.5 to 1.0 cm, based on National Comprehensive Cancer Network (NCCN) guidelines.
What to Ask Your Doctor about Stage 0 Melanoma
When your doctor tells you that you have Stage 0 melanoma, it can be frightening. But it is important to use the time with your doctor to learn as much about your cancer as you can. S/he will provide you important information about your diagnosis and what happens next.
The following questions are those you may want to ask your doctor. Remember, it is ALWAYS okay to ask your doctor to repeat or clarify something s/he said so that you can better understand it. You may find it helpful to print out these questions and bring them with you to your next appointment.