What is esophageal cancer?
Esophageal cancer is the growth of malignant cells usually arising from the lining of the esophagus. Esophageal cancer can be divided into two groups: squamous cell carcinoma and adenocarcinoma. Squamous cell carcinoma may occur throughout the length of the esophagus whereas adenocarcinoma normally occurs just above the esophagogastric junction.
What causes esophageal cancer?
Several factors contribute to the development of esophageal cancer. Alcohol and tobacco consumption are the greatest causative factors for squamous cell esophageal cancer. Dietary factors also play an important role in the development of esophageal cancer. Vitamin A, iron and riboflavin deficiency have been implicated as causes of this form of cancer. The lack of a varied, balanced diet also appears to be contributory. Medical conditions associated with an increased risk of esophageal cancer include tylosis (a rare autosomal-dominant disorder), longstanding untreated achalasia, prior mediastinal irradiation, Barrett's esophagus and chronic reflux esophagitis.
What are the symptoms of esophageal cancer?
Esophageal cancer may be totally asymptomatic in the early stages or may present with nonspecific complaints that may include heartburn, atypical chest pain or dyspepsia. Patients may, on the other hand, present with occult blood in the stool or anemia. Other presenting symptoms may include dysphagia (difficulty swallowing), weight loss or odynophagia (pain on swallowing). Patients may complain of excessive salivation, hoarseness or pulmonary symptoms such as recurrent infections. Later in the disease course the patient may vomit blood from an oozing esophageal tumor or tumor erosion into a vessel.
How is esophageal cancer diagnosed?
Diagnosis may be made with a double-contrast barium esophagram. This test shows nodularity, irregular narrowing, ulceration, abrupt angulation or stiffness of the esophagus. Endoscopy is more sensitive for detection of esophageal cancer because it allows for direct visualization of the affected area and biopsy and/or brush cytology of affected tissue. Additionally, endoscopic ultrasound (EUS), a highly technical, low-risk procedure, allows imaging at close proximity to detect subtle mucosal changes. Screening endoscopy is performed on patients who are at increased risk of developing esophageal cancer such as those with Barrett's esophagus.
Does this condition have a genetic or hereditary link?
Tylosis, a rare autosomal-dominant disorder is the only genetic link to esophageal cancer. Those affected by this condition have a significantly increased chance of developing esophageal cancer by the age of 63 to 65.
The prevalence of esophageal cancer is higher among men. African-American men are four times more likely than white men to get squamous cell carcinoma whereas white men appear to more likely to develop adenocarcinoma. The area from Iran through Afghanistan to Mongolia and northwest to China has a higher incidence of esophageal cancer. This is known as the Asian esophageal cancer belt.
What is the treatment for esophageal cancer?
Surgery offers the best hope for cure of esophageal cancer. Partial or total removal of the esophagus (esophagectomy) with gastric pull-through and primary anastomosis is the most common surgical procedure performed. Occasionally a colonic or small-bowel interposition will be required to connect the esophagus and gastric remnants. This is done by removing a piece of large or small bowel from the patient and attaching it in place of the diseased esophagus.
Radiation therapy, either palliative or curative, is another well-accepted treatment. The treatment may be modified if side effects develop. Chemotherapy (cisplatin-based) in conjunction with radiation therapy has been shown to be superior to radiation therapy alone in patients who are not surgical candidates. Patients with preoperative chemotherapy and radiation have demonstrated disease-free survival after esophagectomy.
Palliative treatment is not curative but improves quality of life. Several endoscopic modalities are used including dilation of the strictured areas after chemotherapy and endoscopic laser therapy for reducing the tumor size. Photodynamic therapy (using a photosensitizing agent and a lower energy laser) causes selective tumor destruction. Esophageal stenting is another important mode of palliation.
Percutaneous endoscopic gastrostomy (PEG) tube placement may be used in patients with an inability to take nutrition in orally to facilitate adequate nutrition.
What complications can arise from the different treatment methods?
Complications of surgery include cardiac and/or lung problems, anastomotic leaks and infection.
Radiation therapy may cause transient worsening of the dysphagia early in the treatment. Radiation esophagitis may develop with continued radiation. Other side effects associated with radiation therapy are hair loss and nausea and vomiting. The latter may be controlled with medication.
Chemotherapy may also have the same gastrointestinal effects as radiation therapy.
The risk of aspiration, perforation and reaction to the sedative given during the procedure are possible complications of endoscopic procedures. Perforation and bleeding are possible complications of stent placement. PEG placement is a low-risk procedure but carries risks similar to stent placement. Photodynamic therapy causes sun sensitivity.
What factors can influence the survival rate with esophageal cancer?
The primary determinants of survival are the size of the primary tumor at diagnosis and the presence of extra-esophageal involvement. Patients with tumors less than 5 cm and no lymph node involvement usually have the best prognosis. Tumors limited to the submucosa have a five-year survival rate of over 60 percent. If the muscularis propria is involved, then the survival rate drops. Involvement of the adventitia, or the innermost layer of the esophagus, decreases the odds of survival. If the cancer is found early and is superficial, the prognosis for a cure with surgical intervention is good. A poorer prognosis is associated with vascular invasion and nodal metastasis.