Esophageal cancer

Esophageal cancer is malignancy of the esophagus. There are various subtypes, primarily squamous cell cancer and adenocarcinoma. Squamous cell cancer arises from the cells that line the upper part of the esophagus. Adenocarcinoma arises from glandular cells that are present at the junction of the esophagus and stomach. Esophageal tumors usually lead to dysphagia (difficulty swallowing), pain and other symptoms, and are diagnosed with biopsy. Small and localized tumors are treated surgically with curative intent. Larger tumors tend not to be operable and hence cannot be cured; their growth can still be delayed with chemotherapy, radiotherapy or a combination of the two. In some cases chemo- and radiotherapy can render these larger tumors operable. Prognosis depends on the extent of the disease and other medical problems, but is fairly poor.

Signs and symptoms

Dysphagia (difficulty swallowing) is the first symptom in most patients. Odynophagia (painful swallowing) may be present. Fluids and soft foods are usually tolerated, while hard or bulky substances (such as bread or meat) cause much more difficulty. Substantial weight loss is characteristic as a result of poor nutrition and the active cancer. Pain, often of a burning nature, may be severe and worsened by swallowing, and can be spasmodic in character. An early sign may be an unusually husky or raspy voice.

The presence of the tumor may disrupt normal peristalsis (the organised swallowing reflex), leading to nausea and vomiting, regurgitation of food, coughing and an increased risk of aspiration pneumonia. The tumor surface may be fragile and bleed, causing hematemesis (vomiting up blood). Compression of local structures occurs in advanced disease, leading to such problems as superior vena cava syndrome. Fistulas may develop between the esophagus and the trachea, increasing the pneumonia risk; this symptom is usually heralded by cough, fever or aspiration.

If the disease has spread elsewhere, this may lead to symptoms related to this: liver metastasis could cause jaundice and ascites, lung metastasis could cause shortness of breath, pleural effusions, etc.

Causes and risk factors

Increased risk

(Barrett's esophagus is considered to be a risk factor for esophageal adenocarcinoma)

There are a number of risk factors for esophageal cancer. Some subtypes of cancer are linked to particular risk factors:

• Age. Most patients are over 60, and the median in US patients is 67.
• Sex. It is more common in men.
• Heredity. It is more likely in people who have close relatives with cancer.
• Tobacco smoking and heavy alcohol use increase the risk, and together appear to increase the risk more than these two individually.
• Gastroesophageal reflux disease (GERD) and its resultant Barrett's esophagus increase esophageal cancer risk due to the chronic irritation of the mucosal lining (adenocarcinoma is more common in this condition, while all other risk factors predispose more for squamous cell carcinoma).
• Human papillomavirus (HPV)
• Swallowing lye or other caustic substances.
• Particular dietary substances, such as nitrosamine.
• A medical history of other head and neck cancers increases the chance of developing a second cancer in the head and neck area, including esophageal cancer.
• Plummer-Vinson syndrome (anemia and esophageal webbing)
• Tylosis and Howel-Evans syndrome (hereditary thickening of the skin of the palms and soles).
• Radiation therapy for other conditions in the mediastinum.
• Celiac disease predisposes towards squamous cell carcinoma.
• Obesity increases the risk of adenocarcinoma fourfold. It is suspected that increased risk of reflux may be behind this association.

Decreased risk

• Risk appears to be less in patients using aspirin or related drugs (NSAIDs).
• The role of Helicobacter pylori in progression to esophageal adenocarcinoma is still uncertain, but, on the basis of population data, it may carry a protective effect. It is postulated that H. pylori prevents chronic gastritis, which is a risk factor for reflux, which in turn is a risk factor for esophageal adenocarcinoma.
• According to the National Cancer Institute, "diets high in cruciferous (cabbage, broccoli, cauliflower) and green and yellow vegetables and fruits are associated with a decreased risk of esophageal cancer."
• Moderate coffee consumption is associated with a decreased risk.
• According to one Italian study of "diet surveys completed by 5,500 Italians" — a study which has raised debates questioning its claims among cancer researchers cited in news reports about it — eating pizza more than once a week appears "to be a favorable indicator of risk for digestive tract neoplasms in this population."

Diagnosis

(Endoscopy and radial endoscopic ultrasound images of submucosal tumour in mid-esophagus.)

Clinical evaluation

Although an occlusive tumor may be suspected on a barium swallow or barium meal, the diagnosis is best made with esophagogastroduodenoscopy (EGD, endoscopy); this involves the passing of a flexible tube down the esophagus and visualising the wall. Biopsies taken of suspicious lesions are then examined histologically for signs of malignancy.

Additional testing is usually performed to estimate the tumor stage. Computed tomography (CT) of the chest, abdomen and pelvis, can evaluate whether the cancer has spread to adjacent tissues or distant organs (especially liver and lymph nodes). The sensitivity of CT scan is limited by its ability to detect masses (e.g. enlarged lymph nodes or involved organs) generally larger than 1 cm. FDG-PET (positron emission tomography) scan is also being used to estimate whether enlarged masses are metabolically active, indicating faster-growing cells that might be expected in cancer. Esophageal endoscopic ultrasound (EUS) can provide staging information regarding the level of tumor invasion, and possible spread to regional lymph nodes.

The location of the tumor is generally measured by the distance from the teeth. The esophagus (25 cm or 10 inches long) is commonly divided into three parts for purposes of determining the location. Adenocarcinomas tend to occur distally and squamous cell carcinomas proximally, but the converse may also be the case.

Histopathology

Most tumors of the esophagus are malignant. A very small proportion (under 10%) is leiomyoma (smooth muscle tumor) or gastrointestinal stromal tumor (GIST). Malignant tumors are generally adenocarcinomas, squamous cell carcinomas, and occasionally small-cell carcinomas. The latter share many properties with small-cell lung cancer, and are relatively sensitive to chemotherapy compared to the other types.

Classification

Esophageal cancers are typically carcinomas which arise from the epithelium, or surface lining, of the esophagus. Most esophageal cancers fall into one of two classes: squamous cell carcinomas, which are similar to head and neck cancer in their appearance and association with tobacco and alcohol consumption, and adenocarcinomas, which are often associated with a history of gastroesophageal reflux disease and Barrett's esophagus.

Treatment

General approaches

(Self-expandable metallic stents are used for the palliation of esophageal cancer)

(Esophageal cancer affecting the lower esophageus. Insets show the tumor in more detail both before and after placement of a stent.)

The treatment is determined by the cellular type of cancer (adenocarcinoma or squamous cell carcinoma vs other types), the stage of the disease, the general condition of the patient and other diseases present. On the whole, adequate nutrition needs to be assured, and adequate dental care is vital.

If the patient cannot swallow at all, a stent may be inserted to keep the esophagus patent; stents may also assist in occluding fistulas. A nasogastric tube may be necessary to continue feeding while treatment for the tumor is given, and some patients require a gastrostomy (feeding hole in the skin that gives direct access to the stomach). The latter two are especially important if the patient tends to aspirate food or saliva into the airways, predisposing for aspiration pneumonia.

Tumor treatments

Surgery is possible if the disease is localised, which is the case in 20-30% of all patients. If the tumor is larger but localised, chemotherapy and/or radiotherapy may occasionally shrink the tumor to the extent that it becomes "operable"; however, this combination of treatments (referred to as neoadjuvant chemoradiation) is still somewhat controversial in most medical circles. Esophagectomy is the removal of a segment of the esophagus; as this shortens the distance between the throat and the stomach, some other segment of the digestive tract (typically the stomach or part of the colon) is placed in the chest cavity and interposed. If the tumor is metastatic, surgical resection is not considered worthwhile, but palliative surgery may offer some benefit.

Laser therapy is the use of high-intensity light to destroy tumor cells; it affects only the treated area. This is typically done if the cancer cannot be removed by surgery. The relief of a blockage can help to reduce dysphagia and pain. Photodynamic therapy (PDT), a type of laser therapy, involves the use of drugs that are absorbed by cancer cells; when exposed to a special light, the drugs become active and destroy the cancer cells.

Chemotherapy depends on the tumor type, but tends to be cisplatin-based (or carboplatin or oxaliplatin) every three weeks with fluorouracil (5-FU) either continuously or every three weeks. In more recent studies, addition of epirubicin (ECF) was better than other comparable regimens in advanced nonresectable cancer. Chemotherapy may be given after surgery (adjuvant, i.e. to reduce risk of recurrence), before surgery (neoadjuvant) or if surgery is not possible; in this case, cisplatin and 5-FU are used. Ongoing trials compare various combinations of chemotherapy; the phase II/III REAL-2 trial - for example - compares four regimens containing epirubicin and either cisplatin or oxaliplatin and either continuously infused fluorouracil or capecitabine.

Radiotherapy is given before, during or after chemotherapy or surgery, and sometimes on its own to control symptoms. In patients with localised disease but contraindications to surgery, "radical radiotherapy" may be used with curative intent.

Follow-up

Patients are followed up frequently after a treatment regimen has been completed. Frequently, other treatments are necessary to improve symptoms and maximize nutrition.

Prognosis

In general, the prognosis of esophageal cancer is quite poor, because so many patients present with advanced disease: The overall five-year survival rate (5YSR) is less than 5%. Individualized prognosis depends largely on stage. Those with cancer restricted entirely to the esophageal mucosa have about an 80% 5YSR, but submucosal involvement brings this down to less than 50%. Extension into the muscularis propria (muscular layer of the esophageus) has meant a 20% 5YSR and extension to the structures adjacent to the esophagus results in a 7% 5YSR. Patients with distant metastases (who are not candidates for curative surgery) have a less than 3% 5YSR. Of all patients undergoing surgery with curative intent, the 5YSR is only about 25%.

Epidemiology

Esophageal cancer is a relatively rare form of cancer, but some world areas have a markedly higher incidence than others: China, India and Japan, as well as the United Kingdom, appear to have a higher incidence, as well as the region around the Caspian Sea.

The American Cancer Society estimates that during 2007, approximately 15,560 new esophageal cancer cases will be diagnosed in the United States.

The esophageal cancer incidence and mortality rates for people of African-American descent have been higher than the rate for Caucasians. According to the NCI, incidence of adenocarcinoma of the esophagus, which is associated with Barrett's esophagus, is rising in the United States. This type is more common in Caucasian men over the age of 60.

Multiple reports indicate that esophageal adenocarcinoma incidence has increased during the past 20 yr, especially in non-Hispanic white men. Esophageal adenocarcinoma age-adjusted incidence increased in New Mexico from 1973 to 1997. This increase was found in non-Hispanic whites and Hispanics and became predominant in non-Hispanic whites.