Metastatic Squamous Cell Carcinoma

Metastatic squamous cell carcinoma is a form of skin cancer that has spread beyond its original location to other parts of the body. While most squamous cell carcinomas are caught early and successfully treated, about 5 percent become advanced, making them far more dangerous and challenging to manage.

Table of contents

• What Is Metastatic Squamous Cell Carcinoma?
• Understanding Squamous Cells
• When Squamous Cell Carcinoma Becomes Advanced
• Metastatic Squamous Neck Cancer with Occult Primary
• Signs and Symptoms
• Tests for Detection and Diagnosis
• How Common Is Metastasis?
• Outlook and Survival
• Treatment Approaches

What Is Metastatic Squamous Cell Carcinoma?

Metastatic squamous cell carcinoma is cancer that started in squamous cells and has spread to other parts of the body beyond the skin. The term “metastasize” means that cancer cells have traveled through the blood or lymph system (a network of vessels that carries fluid throughout the body) to distant locations^[2].

When squamous cell carcinoma spreads, it can move to nearby areas or to distant organs. Cancer that has spread to lymph nodes (small bean-shaped structures that filter fluid in the body) in the neck or around the collarbone is called metastatic squamous neck cancer^[2].

Doctors will try to find where the cancer first started growing, called the primary tumor, because treatment for the spread cancer is the same as treatment for the original site. For example, when lung cancer spreads to the neck, the cancer cells in the neck are lung cancer cells and are treated like lung cancer^[2].

Understanding Squamous Cells

Squamous cells are thin, flat cells found in tissues throughout the body. They form the surface of the skin and line body cavities such as the mouth, as well as hollow organs like blood vessels. They also line the breathing and digestive systems^[2].

Some organs that contain squamous cells include the food pipe (esophagus), lungs, kidneys, and uterus. Cancer can begin in squamous cells anywhere in the body^[2].

Squamous cell carcinoma of the skin starts in the outer layer of skin, called the epidermis. It develops when squamous cells in this layer begin to grow out of control^[3].

When Squamous Cell Carcinoma Becomes Advanced

About 95 percent of squamous cell carcinomas of the skin are found early when they are easiest to treat and cure. The remaining 5 percent have advanced to a point where they are far more dangerous and challenging to treat^[5].

A squamous cell carcinoma is considered advanced when it has spread extensively or aggressively, or when it has resisted multiple treatments and repeatedly come back. These include two main types^[5]:

• Locally advanced squamous cell carcinoma: These are tumors that are large or have pushed deep into underlying tissues, muscles, or nerves. They can be disfiguring or can damage these underlying structures.
• Metastatic squamous cell carcinoma: These are tumors that have spread beyond the original location to other parts of the body. They can be life-threatening.

Metastasis in cutaneous squamous cell carcinoma is rare. However, certain characteristics of the tumor and the patient can increase the risk of spread. When metastasis does occur, it typically happens one to two years after the initial diagnosis^[4].

Metastatic Squamous Neck Cancer with Occult Primary

Sometimes doctors cannot find where in the body the cancer first began to grow. When tests cannot locate a primary tumor, it is called an occult (hidden) primary tumor. In many cases, the primary tumor is never found^[2].

Metastatic squamous neck cancer with occult primary is a disease in which squamous cell cancer spreads to lymph nodes in the neck, but doctors cannot determine where the cancer first formed in the body^[2].

The doctor will try to find the primary tumor by checking organs and tissues in the breathing system, the upper part of the digestive tract (including the lips, mouth, tongue, nose, throat, vocal cords, and part of the food pipe), and other systems^[2].

Signs and Symptoms

The most common signs of metastatic squamous neck cancer with occult primary include a lump or pain in the neck or throat. You should check with your doctor if you have a lump or pain in your neck or throat that doesn’t go away^[2].

These signs and symptoms may be caused by metastatic squamous neck cancer with occult primary, but other conditions can cause the same signs and symptoms^[2].

Tests for Detection and Diagnosis

Tests that examine the tissues of the neck, breathing system, and upper part of the digestive tract are used to find and diagnose metastatic squamous neck cancer and the primary tumor^[2].

In addition to asking about your personal and family health history and doing a physical exam, your doctor may perform several tests. These will include checking for a primary tumor in the organs and tissues of the breathing tract, the upper part of the digestive tract, and other body systems^[2].

How Common Is Metastasis?

Over 1 million people receive a squamous cell carcinoma diagnosis in the United States each year. The rate has risen about 200 percent over the past 30 years^[3].

Prior studies have shown that metastasis rates range from 3 to 9 percent of all squamous cell carcinoma cases^[4]. However, more than 4,000 patients die from this disease every year in the United States^[6].

The rising number of cases, primarily a result of an aging population and increased ultraviolet radiation exposure, represents an emerging health need. While more people are developing squamous cell carcinoma, the vast majority of cases are still found early when they are easier to treat^[6].

Outlook and Survival

The outlook for squamous cell carcinoma depends greatly on whether the cancer is found and treated early. When detected early, squamous cell carcinoma has a 99 percent five-year survival rate. This means that 99 out of 100 people are alive five years after diagnosis^[3].

However, once squamous cell carcinoma has spread to the lymph nodes and beyond, the survival rates are lower. Yet even in its advanced stages, this cancer is still treatable with surgery and other treatments^[3].

Your doctor will give you an outlook based on your medical history, along with the location and extent of your cancer. Together you can decide on the best treatment approach^[5].

Treatment Approaches

If you’ve been diagnosed with advanced squamous cell carcinoma, your doctor may recommend an evaluation by a team of specialists to explore treatment options. The team may include your skin doctor and surgeon, along with physicians and surgeons from other specialties^[5].

Treatment for metastatic cancer is the same as treatment for the primary tumor. The approach depends on where the cancer started and where it has spread^[2].

In the past, various treatments have been tried, including certain chemotherapy drugs. Recently, newer treatments called immunotherapies (medications that help the body’s immune system fight cancer) have shown promising results. These include drugs that work by blocking certain proteins, giving patients with advanced squamous cell carcinoma a new option for treating and managing the disease^[5][6].

Treatment options may include surgery, radiation therapy, or newer immunotherapy medications. Multiple combinations of treatments have been tested with varying degrees of success^[6].