Esophageal cancer

Esophageal cancer is malignancyof the esophagus. There are various subtypes. Esophageal tumors usually lead to dysphagia(difficulty swallowing), pain and other symptoms, and is diagnosed with biopsy. Small and localized tumors are treated with surgery, and advanced tumors are treated with chemotherapy, radiotherapyor combinations. 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 breador meat) cause much more difficulty. Substantial weight lossis 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.

The presence of the tumor may disrupt normal peristalsis(the organised swallowing reflex), leading to nauseaand vomiting, regurgitationof food, coughingand 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 caval obstruction(SVCO). Fistulasmay develop between the esophagus and the trachea, increasing the pneumonia risk; this symptom is usually heralded by cough, feveror aspiration (Enzinger & Mayer 2003).

If the disease has spreadto elsewhere, this may lead to symptoms related to this: livermetastasis could cause jaundiceand ascites, lungmetastasis could cause shortness of breath, pleural effusions, etc.

Cause and risk factors

Increased risk

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 (Enzinger & Mayer 2003).
• Sex. It is more common in men.
• Tobacco smokingand heavy alcoholuse increase the risk, and together appear to increase the risk more than these two individually.
• Swallowing lyeor other caustic substances.
• Particular dietary substances, such as nitrosamine.
• A medical history of other head and neck cancersincreases the chance of developing a second cancer in the head and neck area, including esophageal cancer.
• Plummer-Vinson syndrome(anemia and esophageal webbing)
• Tylosisand Howel-Evans syndrome(hereditary thickening of the skin of the palms and soles).
• Radiation therapyfor other conditions in the mediastinum (Enzinger & Mayer 2003).
• Gastroesophageal reflux disease(GERD) and its resultant Barrett's esophagusincrease oesophageal cancer risk due to the chronic irritation of the mucosal lining (adenocarcinomais more common in this condition), while all other risk factors predispose more for squamous cell carcinoma.

Decreased risk

Risk appears to be less in patients using aspirinor related drugs (NSAIDs). Statistically, it appears that Helicobacter pylori, known for increasing risk for gastric cancer, actually decreases the risk of esophageal cancer (O'Connor 1999); the exact mechanism for this phenomenon is unclear.

Diagnosis

Although an occlusive tumor may be suspected on a barium swallowor 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. Biopsiestaken of suspicious lesions are then examined histologicallyfor signs of malignancy.

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.

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.

Staging

If biopsy suggests esophageal cancer, treatment is determined by the stage of the disease. Establishing the stage of the disease, a process termed staging, usually involves computed tomography(CT scan) of the chest and abdomen. If bone metastasis is suspected (e.g. pain or fracture), a bone scanmay be performed, and bronchoscopymay be performed if the tumor is suspected to involve the tracheaor bronchi. In recent years endoscopic ultrasound(EUS) has been used increasingly to assess local lymph node involvement, and is considered superior to CT for this indication.

The TNMclassification is used to express the extent of the cancer:

• Tumorextent: TX (can't be assessed), T0 (cannot be detected), Tis (carcinoma in situ), T1 (invades lamina propriaor submucosa), T2 (invades muscularis propria), T3 (invades adventitia), T4 (invades adjacent structures)
• Lymph nodeinvolvement: NX (can't be assessed), N0 (none), N1 (present)
• Metastasiselsewhere: M0 (no metastasis) or M1 (distal metastasis present). M1a is used for localised metastasis in some situations, with M1b indicating metastasis outside this area.

The TNM information is sometimes aggregated into AJCCstages:

• Stage 0: Tis, N0, M0 (non-invasive tumor)
• Stage I: T1, N0, M0
• Stage IIA: T2 or T3, N0, M0
• Stage IIB: T1 or T2, N1, M0
• Stage III: T3, N1, M0 or T4, Any N, M0
• Stage IV: Any T, Any N, M1
• Stage IVA: Any T, Any N, M1a
• Stage IVB: Any T, Any N, M1b

Treatment

General approaches

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 nutritionneeds to be assured, and adequate dental care is vital.

If the patient cannot swallow at all, a stentmay be inserted to keep the esophagus patent; stents may also assist in occluding fistulas. A nasogastric tubemay 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

Surgeryis 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. Esophagectomyis 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 stomachor part of the colon) is placed in the chest cavity and interposed. If the tumor is metastatic, surgical resection is not considered worthwile, but palliative surgery may offer some benefit.

Lasertherapy 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.

Chemotherapydepends on the tumor type, but tends to be cisplatin-based (or carboplatinor 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 (Ross et al 2002). 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 epirubicinand either cisplatinor oxaliplatinand either continuously infused fluorouracil or capecitabine.

Radiotherapyis 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 and prognosis

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

Prognosis of esophageal cancer is fairly poor. Even in patients who undergo surgery with curative intent, the five year survival rate is only 25%, and prognosis is poorer in those who are not fit for surgery. Early emphasis on symptom control and palliative caremay improve the quality of life.

Epidemiology

Esophageal cancer is a relatively rare form of cancer, but some world areas have a markedly higher incidence than others: China, Indiaand Japan, as well as the United Kingdom, appear to have a higher incidence, as well as the region around the Caspian Sea(Stewart & Kleihues 2003).

Annual incidence is between 3-11 per 100,000 for males and 0.6-6 per 100,000 for females (Stewart & Kleihues 2003).

References

• Enzinger PC, Mayer RJ. Esophageal cancer. N Engl J Med 2003;349:2241-52. PMID 14657432.
• O'Connor HJ. Helicobacter pylori and gastro-oesophageal reflux disease-clinical implications and management. Aliment Pharmacol Ther 1999;13:117-27. PMID 10102940.
• Ross P, Nicolson M, Cunningham D, Valle J, Seymour M, Harper P, Price T, Anderson H, Iveson T, Hickish T, Lofts F, Norman A. Prospective randomized trial comparing mitomycin, cisplatin, and protracted venous-infusion fluorouracil (PVI 5-FU) with epirubicin, cisplatin, and PVI 5-FU in advanced esophagogastric cancer. J Clin Oncol 2002;20:1996-2004. PMID 11956258.
• Stewart BW, Kleihues P (editors). World cancer report. Lyon: IARC, 2003. ISBN 9283204115.

External links

• NCI Esophageal Cancer Home Page
• Cathy's EC Cafe

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This article is licensed under the GNU Free Documentation License.
It uses material from the http://en.wikipedia.org/wiki/Esophageal+cancer Wikipedia article Esophageal cancer.