Epidemiology:
Most commonly a disease of the older population, rare in>25 years old. Estimated squamos incidence in each third of the esophagus is as follows; upper third 10-25%; middle third, 40-50%; lower third 25-50%. 5% incidence due to achalasia of >=25 years.1⁰
Etiology:
Risk factors for squamous cell: Alcohol, tobacco, dietary factors, more than 25 years of achalasia, and caustic burns (especially lye corrosion).
Risk facors for adenocarcinoma: Barrett's esophagus, chronic esophageal reflux.1⁰

Signs & Symptoms:
Symtoms usually start 3 or 4 months before diagnosis. Dysphagia and weight loss are seen in over 90% of patients. Odynophagia (pain on swallowing) is present in up to 50% of patients.1⁰
Diagnostic Procedures:
The diagnostic workup according to Chao is the following order. First, a history and physical is taken of the patient. Second, a double contrast esophogram is done in diagnostics. Third, a endoscopy is done along with a brushing. Fourth, a CT or MRI are done. CT has an accuracy of 51-70% chance of detecting mediastinal nodes and about a 79% of finding left gastric or celiac node involvement. However, if CT is combined with PET scan the opportunity to diagnos metastasis sooner is of greater chance. Fifth, a patient would get a routine chest x-ray along with labs. Then an endoscopic ultrasound would be performed to evaluate if it is limited to the esophagus or not. Finally, this would help determine which route the patient is suggested to go for treatment.⁶
Histology:
The histology of the esophagus includes squamous cell carcinoma, adenocarcinoma, adenoid cystic carcinoma, mucoepidermoid carcinoma, adenosquamous carcinoma, and undifferentiated carcinoma.⁷
Lymph Node Drainage:
"The esophagus has a dual longitudinal interconnecting system of lymphatics." "...The entire esophagus is at risk for lymphatic metastasis." The esophagus has the ability to "skip areas" up to about 8cm from origination of the tumor to where it has metastisized to. Also, up to 70% of patients were to have metastasis found at the time of autopsy.⁶
Metastatic Spread:
According to Chao, et. al., 80% of patient's have locally extensive and/or metastatic disease at the time of presentation. Local extension from cervical esophagus: larynx, trachea, prevertebral fascia; local extension from upper thoracic esophagus: aorta, trachea, prevertebral fascia; local extension from midthoracic esophagus: aorta, pericardium, left main stem bronchus, prevertebral fascia; local extenstion from lower thoracic esophagus: aorta, pericardium diaphragm, prevertebral fascia.¹ The typical sites of metastatic disease are and percentage of involvement are as follows: 45% to the abdominal lymph nodes; 35% to the liver; 20% to the lung; 18% to the supraclavicular region; 9% to bone and 5% to the adrenal glands.²
Grading:
General grading system recommended by the American Joint Committee on Cancer and the International Union Against Cancer is based on the degree of cell differentiation:
Grade 1: low grade, cells well-differentiated.
Grade 2: moderate grade, cells moderately differentiated.
Grade 3: high grade, cells undifferentiated.
There is also a classification of that the grade can't be assessed.³
Adenocarcinoma of the esopahgus possibly progresses from gasteroenteral reflux disease to Barrett's metaplasia to low-grade dysplasia to high-grade dysplasia to adenocarcinoma.⁴

Staging:
The staging system for esophageal cancer is the American Joint Committee on Cancer and is as follows⁵:

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Radiation Side Effects:
Side effects of radiation therapy may include:
  • skin changes -- ranging from something like a sunburn to blistering and open sores
  • nausea and vomiting
  • diarrhea
  • fatigue
  • painful sores in the mouth and throat
These side effects are often worse if chemotherapy is given at the same time as radiation. During treatment of the esophagus, the radiation kills the normal cells in the lining, leading to painful swallowing⁹
Prognosis:
Esophageal cancer usually manifest as advanced stage disease. 75% of patients have disease lymph nodes at initial presentation. The 5 year survival rate is only 3% for these patients, whereas it is 42% for patients who do not have nodal involvement. Approximately 18% of patients will have distant metastases, typically to abdominal lymph nodes (45% of cases). Liver (35%), lung (20%), supraclavicular nodes (18%), bone (9%), or adrenal glands (5%). Consequently, the prognosis is poor, with surgical cure achieved in less than 10% of patients. Upper 1/3 lesions do better than those in the lower 1/3rd. Tumors 5cm or smaller are 40% resectable, while tumors larger than 5cm have a 75% chance of distant metastasis.⁸
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 esophagus) 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%⁹

Treatments:
The options for treatment of cancer of the esophagus include surgery, chemotherapy, and radiation therapy. Other treatments, such as endoscopic mucosal resection, radiofrequency ablation, and photodynamic therapy, may be used for early cancers and precancers of the esophagus. Some of these treatments can also be used as palliative treatment when all the cancer cannot be removed. Palliative treatment is meant to relieve symptoms, such as pain and trouble swallowing, but is not expected to cure the cancer. Depending on the stage of the cancer and your general medical condition, different treatment options may be used alone or in combination⁹
Radiation Treatment- af field margin of 5 to 6 cm, above and below the tumor, generally is recommended.
some recommend placing tghe patient in the prone position for treatment to move the esophagus away from th espinal cord. Lesions in the upper cervical or postcricoid esophagus usually are treated from the laryngopharynx to the carina.supraclaviculaar and superior mediastinal noses are irradiated electively. this can be done with lateral parallel oppossed or oblique portals to the primary tumor and a single AP field for the supraclavicular and superior mediastinal nodes. Irradiation firlds for lesions in the lower two-thirds of the esohagus (thoracis esophagus) include the entire thoracis esophagus and bilateral supraclavicular nodes in the initail treametn volume. the inferior margin of the initial fields always includes the esophagogastric junction and, for lower-third lesions, the celiac plexus. At lest 5cm of normal tissue id included above and below the gross disease
Doses- based on data from squamous cell carcinoma of the upper aerodigestive tract, 50 Gy at 1.8 to 2.0 Gy per fraction over 5 weeks should control more than 90% of subclinical disease.
1. at least 60-70 Gy is needed for gross disease in fractions of 1.8-2.0 Gy per day, 5 days per week.
2. in addition to exgternal beam therapy, intracavitary therapy can be used as part of a radical or pallative treatment plan. The most common techinque is iridim 192 afterloading. In general 10-20 Gy is delivered using this technique.
3. Another method used to cone down on middle -third lesions is a 360 degree rotation.⁸

TD5/5:
Organ (1/3), (2/3), (3/3)
Esophagus 60 Gy, 58 Gy, 55 Gy
Heart 60 Gy, 45 Gy, 40 Gy
Lung 45 Gy, 30 Gy, 17.5 Gy
Spinal cord 50 Gy, 50 Gy, 47 Gy¹¹


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Figure 1: IMRT Esophagus with DRR from Eclipse¹²


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Figure 2: Anterior-posterior, 3 field, and wedged pair arrangements¹¹

References
1. Chao KS, Perez CA., Brady LW. Radiation Oncology - Management Decisions. 2nd ed. Philadelphia, PA: Lippincott, Williams & Wilkins; 2002:336.

2. Chao KS, Perez CA., Brady LW. Radiation Oncology - Management Decisions. 2nd ed. Philadelphia, PA: Lippincott, Williams & Wilkins; 2002:336.
3. Spitalnik PF, di Sant'agnese PA. The Pathology of cancer. In: Rubin P, ed. Clinical Oncology: A Multidisciplinary Approach for Physicians and Students. 8th ed.Philadelphia, PA: W.B. Saunders Company; 2001:54.
4. Fisichella PM, Patti MG. Esophageal cancer. Available at: //http://emedicine.medscape.com/article/277930-overview//. Accessed January 18, 2010.
5.Gunderson LL, Haddock MG, Goldberg, R, et. al. Alimentary cancer. In: Rubin P, ed. Clinical Oncology: A Multidisciplinary Approach for Physicians and Students. 8th ed.Philadelphia, PA: W.B. Saunders Company; 2001:688.
6. Chao KS, Perez CA., Brady LW. Radiation Oncology - Management Decisions. 2nd ed. Philadelphia, PA: Lippincott, Williams & Wilkins; 2002.
7. Washington CM, Leaver D. Principles and Practice of Radiation Therapy. 2nd ed. St. Louis, MO: Mosby. 2004


8. Chao KS, Perez CA, Brady LW. Radiation Oncology- Management Decisions. 2nd ed.
Philadelphia, PA: Lippincott, Williams & Wilkins; 2002
9. Copyright 2010 © American Cancer Society, Inc.
www.acs.org/esophagus.com. Accessed January 12, 2010
10. Chao KS, Perez CA., Brady LW. Radiation Oncology - Management Decisions. 2nd ed. Philadelphia, PA: Lippincott, Williams & Wilkins; 2002.
11. Chao KS, Perez CA., Brady LW. Radiation Oncology - Management Decisions. 2nd ed. Philadelphia, PA: Lippincott, Williams & Wilkins. 2002.
12. United Hospital. Eclipse planning system. Accessed January 21, 2010.