Skin cancer is the most common human cancer. It is thought to be more common than all other cancer types combined. The majority of skin cancers are caused by sun exposure, sun burns, and/or tanning bed exposure, typically years prior to the development of the cancer. However, skin cancer can develop in any site, including those typically protected from the sun, so it is important to have full body skin checks for complete skin cancer screening.
There are three main types of skin cancer: basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and melanoma. Sometimes, BCCs and SCCs are lumped together into a category called non-melanoma skin cancers (NMSCs). NMSC is usually but not always less aggressive than melanoma.
Basal cell carcinoma (BCC) is the most common of the three types. While generally less aggressive than the other two types, basal cell skin cancers can destroy local tissue and in extremely rare cases, spread to the lymph nodes and elsewhere in the body. Depending on the location, size, and subtype (the way the cancer cells look under the microscope) of your basal cell, options for treatment may include Mohs micrographic surgery, standard excision (also known as wide local excision), electrodessication and curettage (also known as an ED&C, or the “scrape and burn” technique), or topical chemotherapy creams.
I think of squamous cell carcinoma (SCC) as the intermediate skin cancer, both in terms of how aggressive it is and how common it is. Many squamous cell skin cancers are slow-growing and easily treatable; however, up to 5% can have serious complications, including recurrence after treatment, spread to the lymph nodes or elsewhere in the body, and even death. For this reason, SCC must be taken very seriously. In general, topical treatments, such as ED&C and chemotherapy creams are less useful for SCC, and standard excision or Mohs micrographic surgery are better options in order to ensure complete removal and reduce the risk of complications. Some squamous cell carcinomas are confined to the top layer of the skin only and are called squamous cell carcinoma in situ (SCCIS). These are early stage SCCs and have a wide range of treatment options similar to those used for BCCs.
Melanoma is the least common but most aggressive of the three types of skin cancer. Melanomas carry the highest risk for metastasis to other sites in the body and death related to skin cancer. The risk for a particular melanoma relates directly to how deep the cancer cells are found in the skin, measured in millimeters. Dermatologists and dermatologic surgeons like myself treat lower-risk melanomas, which are defined as either melanomas in situ (MIS) or T1a melanomas (less than 0.8mm in depth without ulceration). These relatively superficial melanomas are almost always treated surgically, either with wide local excision or something called “slow Mohs,” a procedure done over several days in which tissue is removed and examined under the microscope prior to sewing the area closed. This process may take up to a week and may have to be repeated to remove all the cancer. If you have a deeper melanoma, you will likely be referred to a surgical oncologist, a type of surgeon who specializes in a procedure called a sentinel lymph node biopsy, which allows the lymph nodes to be checked for melanoma cancer cells at the same time as the removal of the skin cancer.
Frequently Asked Questions
Do I still need to have a procedure if my biopsy looks entirely healed up?
Can basal cell carcinoma turn into melanoma (or, more generally, can one type of skin cancer turn into another type)?
Why do I need Mohs surgery for one skin cancer and not for a different skin cancer?
Am I going to get another one of these skin cancers?
What can I do to prevent getting an additional skin cancer and/or to catch any additional skin cancers early?
What are the chances of this skin cancer coming back?