Non-Melanoma Skin Cancer: A Growing Epidemic
Skin cancer is the most commonly diagnosed cancer
. Some form of skin cancer is diagnosed in more than two million people each year in the U.S. The vast majority of skin cancers (over 90%) are of the non-melanoma
variety, with most being basal cell (BCC) and squamous cell carcinomas
(SCC). While they have malignant potential, most BCC and SCC are unlikely to spread to other parts of the body when caught early. They may be locally disfiguring if not treated. Because non-melanoma skin cancers rarely metastasize, the prognosis is generally very good. There are certain characteristics, however, that are linked with a higher risk of recurrence or metastasis. Some of these high risk features are large tumor size, greater tumor depth, poorly defined tumor border, aggressive tumor growth pattern, tumor invasion near nerves or blood vessels, recurrent tumors, and tumor location in the head and neck region.
Treatment of most non-melanoma skin cancers depends on the size and location of the cancer, whether it is a BCC or SCC, patient age, and overall medical condition. Treatment of the majority of BCC and SCC most often involves surgery, but there are non-surgical approaches that may be considered in certain situations. With surgery, the goal is to destroy or remove the entire skin cancer with a margin of cancer-free tissue around the tumor.
There are different types of skin cancer surgery and the choice of which to use depends in part on the characteristics and location of the tumor. Mohs micrographic surgery is a highly specialized type of surgery for skin cancer and requires special expertise. The Mohs procedure removes the skin cancer one layer at a time, checking each layer for
cancer cells, until it is completely cleared. The Mohs procedure removes the least amount of normal tissue and also has the highest published surgical cure rates for both primary and recurrent skin cancers. Other common types of skin cancer surgery are simple excision and curettage with electrodesiccation
. Simple excision involves the use of a scalpel to remove the skin cancer with a small margin of surrounding normal tissue. Curettage uses a spoon-shaped instrument (curette) to scrape off the skin cancer and electrodesiccation
uses an electric current to cauterize the edges to control bleeding and destroy any remaining tumor cells.
Common non-surgical treatment options for skin cancer
, topical therapy, and radiotherapy. Cryotherapy
is used to destroy a skin cancer by freezing it with liquid nitrogen. Topical skin cancer therapy involves application
of medications like 5-fluorouracil
(5-FU) or Aldara (imiquimod) directly to the tumor on the skin. Radiotherapy for skin cancer is completely non-invasive and uses high-energy X-rays to kill
cancer cells by preventing them from growing and dividing. Common types of radiotherapy used to treat skin cancer include electron therapy, superficial or orthovoltage
therapy, and brachytherapy. Like Mohs surgery, treatment with radiotherapy is very technical and, in order to optimize outcomes, requires expert involvement of a highly trained team of personnel, including radiation oncologist
, radiation physicist/ dosimetrist
, and radiation therapist. Radiotherapy may be appropriate for older patients with wound-healing problems who cannot tolerate surgery or in cases where surgery may be difficult and/or disfiguring. Sometimes, radiotherapy is recommended after surgery to kill any residual cancer cells that may be hiding in the operated region.
When diagnosed in the early stages, the cure rates for BCC and SCC are very high (over 95%) with good cosmetic outcomes. Within the first five years after diagnosis of a non-melanoma skin cancer, between 30% and 50% of patients will develop another
non-melanoma skin cancer. Patients who have had non-melanoma skin cancer are also at an increased risk for developing melanoma, which are known to be more aggressive and challenging to treat.
Dr. Sophia Rahman is a radiation oncologist with Diablo Valley Oncology. Located in the California Cancer and Research Institute at 400 Taylor Blvd in Pleasant Hill, the practice is home to the largest single site for cancer treatment in Contra Costa County.
Tags: Skin Cancer