Skin Squamous Cell Carcinoma Metastatic
When skin squamous cell carcinoma spreads beyond its original location to other parts of the body, it becomes a life-threatening condition that requires specialized treatment approaches and careful medical management.
Table of contents
- What is Metastatic Squamous Cell Carcinoma
- How Rare is Metastasis
- Types of Advanced Disease
- Who is Affected
- Causes and Risk Factors
- Signs and Symptoms
- Diagnosis and Testing
- Treatment Options
- Prognosis and Survival
What is Metastatic Squamous Cell Carcinoma
Metastatic squamous cell carcinoma is cancer that has spread to other parts of the body beyond the skin[1]. Squamous cells are thin, flat cells that make up the middle and outer layers of the skin. When cancer starts in these cells and then travels to other locations, it is called metastatic disease[1].
The cancer can spread through the blood or lymph system to lymph nodes in the neck, around the collarbone, or to other organs in the body[3]. When this happens, doctors will try to find the original tumor because treatment depends on where the cancer first started. However, in some cases, the original tumor may be hard to find[2].
How Rare is Metastasis
Metastasis of skin squamous cell carcinoma is relatively rare, but it can be life-threatening when it occurs[2]. Studies show that metastasis rates range from 3 to 9 percent of all cases[2]. When metastasis does occur, it typically happens one to two years after the initial diagnosis[2].
About 95 percent of squamous cell carcinomas of the skin are detected early, when they are easiest to treat and cure. The remaining 5 percent of cases have advanced to such an extent that they are far more dangerous and challenging to treat[4].
Types of Advanced Disease
When squamous cell carcinoma of the skin has spread extensively or aggressively, or has resisted multiple treatments and repeatedly returned, it is considered to be advanced. These tumors fall into two main categories[4].
Locally advanced squamous cell carcinoma includes tumors that are large or have penetrated deep into underlying tissues, muscles or nerves. These cancers can be disfiguring and can damage these underlying structures[4].
Metastatic squamous cell carcinoma refers to tumors that have spread beyond the original location to other parts of the body. These cancers can be life-threatening[4].
Who is Affected
Over 1 million people receive a squamous cell carcinoma diagnosis in the United States each year[3]. The rate of this cancer has risen about 200 percent over the past 30 years[3].
You are most at risk if you have long-term sun exposure or sun damage to your skin at a young age, have a pale complexion with blue or green eyes and blonde or red hair, are 65 years of age or older, have a weak immune system or received an organ transplant, or had chemical exposure from cigarettes or arsenic[3].
Males are about two times more likely to develop squamous cell carcinoma. People over the age of 50 are most likely to get this cancer, but the incidence has been rising in people younger than 50[3].
Causes and Risk Factors
A mutation to the p53 gene causes squamous cell carcinoma. The most common way that this gene mutates is from ultraviolet (UV) exposure from the sun, or from using indoor tanning beds[3].
The p53 gene provides instructions for your cells to divide and replicate to replace cells when they reach the end of their lifespan. This gene is a tumor suppressor, which means that it controls how much and how often your cells divide[3].
Most squamous cell carcinomas of the skin are caused by too much ultraviolet radiation. This comes either from sunlight or from tanning beds or lamps. Protecting your skin from UV light can help reduce the risk of squamous cell carcinoma of the skin[1].
Certain tumor and patient characteristics increase the risk of metastasis. These include the location, size, and depth of the tumor, among others[2]. More than 4,000 patients die from this disease every year in the United States[5].
Signs and Symptoms
Symptoms of squamous cell carcinoma include skin changes such as a rough-feeling bump or growth which might crust over like a scab and bleed, a growth that is higher than the skin around it but sinks down in the middle, a wound or sore that will not heal or a sore that heals and then comes back, or an area of skin that is flat, scaly and red and larger, about 1 inch in size[3].
When metastatic squamous cell cancer spreads to lymph nodes in the neck, signs and symptoms may include a lump or pain in the neck or throat[2]. A lesion that has been present for one year and is skin-colored and firm may also be a sign of metastatic disease[2].
Squamous cell carcinoma of the skin most often occurs on sun-exposed skin, including the scalp, the backs of the hands, the ears, or the lips[1]. In people with Black and brown skin, squamous cell carcinomas are more likely to be on skin that is not exposed to sun, such as the genitals[1].
Diagnosis and Testing
Tests and procedures used to diagnose squamous cell carcinoma of the skin include a physical exam and a biopsy[8]. During the physical exam, a member of your health care team asks about your health history and looks at your skin for signs of squamous cell carcinoma[8].
A biopsy is a procedure to remove a sample of tissue for testing in a lab. A member of your health care team uses a tool to cut away, shave off or punch out some or all of the area of skin that looks unusual. The sample is tested in a lab to see if it is cancer[8].
If you have been diagnosed with advanced squamous cell carcinoma, your doctor may recommend an evaluation by a multidisciplinary team to explore treatment options. The team may include your dermatologist and surgeons from other specialties. There are new tools, including genomic testing, that are helping dermatologists make more informed decisions to improve health outcomes[4].
Treatment Options
Most squamous cell carcinomas of the skin can be removed with minor surgery. Some are removed with a medicine applied to the skin. The treatment depends on where the cancer is, how large it is, how fast it is growing and what you prefer[8].
However, only a limited number of rigorous studies of the treatment of advanced squamous cell carcinoma have been undertaken. In the past, various agents have been explored in a limited fashion, including chemotherapy with cisplatin, fluoropyrimidines, bleomycin, and doxorubicin, as well as 13-cis-retinoic acid and interferon-α2a[7].
Recently, the field of immunotherapy is growing, giving patients with advanced squamous cell carcinoma a new option for treating and managing the disease[4]. Agents targeting the human epidermal growth factor receptor, such as erlotinib, gefitinib, and cetuximab, have displayed preliminary evidence of activity in phase II clinical trials and case reports[7].
Multiple combinations of chemotherapy have been tested with variable success, but no rigorous randomized studies have been conducted[5]. As such, the treatment of locally advanced and metastatic squamous cell carcinoma of the skin is an area that needs more clinical investigation[5].
Prognosis and Survival
Squamous cell carcinoma of the skin is usually not life-threatening. But if it is not treated, squamous cell carcinoma of the skin can grow large or spread to other parts of the body. The growth of the cancer can cause serious complications[1].
The prognosis for skin squamous cell carcinoma after definitive treatment is generally good, with three-year disease-specific survival of around 85 percent[5]. However, advanced disease carries a more serious prognosis. Treatment to remove cancer leads to a positive prognosis if the cancer is found and treated early[3].
In the central and southern United States, which are areas of high sun exposure, the mortality from squamous cell carcinoma of the skin may actually be comparable to common cancers such as melanoma, leukemia, non-Hodgkin lymphoma, renal, and bladder cancer[5].
