Esophageal squamous cell carcinoma is a type of cancer originating in the esophagus, the muscular tube that moves food from the throat to the stomach. This cancer develops in the squamous cells, which are the thin, flat cells making up most of the esophageal lining. Esophageal squamous cell carcinoma, or ESCC, is one of the two primary classifications of esophageal cancer. While it is the most prevalent type globally, its incidence has decreased in the United States and other Western nations.
Causes and Risk Factors
The development of ESCC is strongly associated with factors that cause repeated irritation to the esophageal lining. Tobacco use, including smoking and chewing tobacco, is a major risk factor. Heavy alcohol consumption also elevates the risk, and the combination of smoking and drinking creates a synergistic effect, increasing the risk far more than either factor alone.
Dietary habits play a substantial role. Diets low in fruits and vegetables are linked to a higher incidence. Frequently drinking very hot liquids, at 149°F (65°C) or higher, can cause long-term thermal injury. A high intake of foods that are salted, pickled, or contain nitrosamines found in some processed meats is also a contributing factor.
Certain pre-existing medical conditions can predispose an individual to ESCC. Achalasia, a rare disorder that impairs the esophagus’s ability to move food toward the stomach, is one such condition. A history of other head and neck cancers also elevates the risk, which may be due to shared risk factors. There is also evidence linking human papillomavirus (HPV) infection to an increased risk.
Direct injury to the esophagus from caustic substances, such as accidentally swallowing lye, can lead to a higher long-term risk. Rare genetic conditions, like tylosis, which causes thickening of the skin on the palms and soles, are also associated with a very high lifetime risk of this cancer.
Signs and Symptoms
The signs of ESCC often do not appear until the disease has progressed, as the esophagus can stretch to accommodate early tumor growth. The most common symptom is progressive dysphagia, or difficulty swallowing. This typically begins with a sensation of solid foods getting stuck in the throat or chest and gradually worsens to include softer foods and eventually liquids.
Odynophagia, or painful swallowing, can occur when the passage of food irritates the tumor. A person might feel pain, pressure, or a burning sensation in the middle of the chest, which can be mistaken for heartburn. Unexplained and significant weight loss is another frequent sign.
Changes in voice, such as persistent hoarseness, or a chronic cough can develop if the tumor affects nerves connected to the larynx. In some cases, the tumor may bleed, leading to vomiting blood or the presence of black, tarry stools. This slow blood loss can lead to anemia and fatigue.
Diagnosis and Staging Process
The primary diagnostic tool is an upper endoscopy, also known as an esophagogastroduodenoscopy (EGD). During this procedure, a doctor guides a thin, flexible tube with a camera down the throat to visually inspect the lining of the esophagus, stomach, and the first part of the small intestine.
If an abnormal area is identified during the endoscopy, a biopsy is performed by taking a small tissue sample from the lesion. A pathologist then examines the tissue for the presence of cancer cells. A biopsy is the only way to provide a definitive diagnosis of ESCC.
Once a diagnosis is confirmed, the next step is determining the cancer’s stage, which describes its size and whether it has spread. Imaging tests are used, including a computed tomography (CT) scan of the neck, chest, and abdomen to look for spread to lymph nodes or distant organs. A positron emission tomography (PET) scan, often combined with a CT scan (PET-CT), can help identify cancer cells throughout the body.
An endoscopic ultrasound (EUS) is a specialized procedure that provides detailed images of the esophageal wall and surrounding tissues. It is used to assess how deeply the tumor has grown and whether it has invaded nearby lymph nodes. The information from these tests is combined to assign a stage using the TNM (Tumor, Node, Metastasis) system.
Treatment Approaches
The treatment plan for esophageal squamous cell carcinoma is highly dependent on the stage of the cancer at diagnosis. For very early-stage cancers confined to the superficial layers of the esophagus, treatment may involve endoscopic procedures. Techniques like endoscopic mucosal resection (EMR) or endoscopic submucosal dissection (ESD) allow for removing cancerous tissue through an endoscope without major surgery.
For cancers that have grown deeper into the esophageal wall but have not spread to distant sites, a combination of treatments is often employed. Surgery, known as an esophagectomy, to remove all or part of the esophagus is a common approach. This is often preceded by neoadjuvant therapy, which involves chemoradiation given before the operation to shrink the tumor.
In some cases, particularly for tumors in the upper esophagus or for patients who are not suitable for surgery, definitive chemoradiation may be used as the primary treatment. Chemotherapy uses drugs to kill cancer cells, while radiation therapy uses high-energy rays to target them. The combination of these therapies can be an effective treatment.
For advanced or metastatic ESCC, where the cancer has spread to distant organs, the focus of treatment shifts to control and symptom management. Chemotherapy is the mainstay of treatment to help slow the cancer’s growth. Newer treatments include targeted therapy, which attacks specific vulnerabilities in cancer cells, and immunotherapy, which helps the body’s own immune system fight cancer.
Prognosis and Survival Rates
The prognosis for ESCC is closely linked to the stage at diagnosis. Because symptoms often do not appear until the disease is advanced, it is frequently diagnosed at a later stage, which can make treatment more challenging and affect the outlook.
Survival rates are statistics that provide a general idea of outcomes and are often given as a 5-year relative survival rate. This rate compares people with the cancer to the general population. According to data from the National Cancer Institute, for esophageal cancer diagnosed between 2014 and 2020, the 5-year relative survival rate for localized disease is 48%.
When the cancer has spread to nearby tissues or lymph nodes (regional stage), the 5-year relative survival rate is 28%. For distant-stage cancer, where it has spread to faraway parts of the body, the rate is 5%. It is important to remember that these figures are averages and cannot predict an individual’s case.