Esophageal cancer (EC) is  cancer that occurs in the esophagus (a long hollow tube that connects the throat to the stomach). Usually, it develops in the cells that line the internal  parts of the esophagus. It can occur anywhere along the length of the esophagus. Globally, it is the sixth most frequent cause of cancer-related fatalities. Esophageal cancer affects  men more commonly as compared to the women. The use of alcohol and tobacco products, as well as certain absurd dietary practices, and obesity may all contribute to a greater incidence of esophageal cancer.

Symptoms

In the initial stages, any prominent signs and symptoms of this disease may not be seen. But gradually as the disease progresses the patient may experience:

• Dysphagia (Problem with swallowing)

• Loss of weight without effort

• Discomfort or burning sensation in the chest accompanied by pain

• Heartburn

• Inability to digest which becomes severe in later stages of the disease

Barrett’s esophagus, a precancerous condition that occurs due to chronic gastrointestinal reflux may also transform into esophageal cancer in the later stages.

Esophageal cancer can occur when a malignant tumor forms in the lining of the esophagus.

Diagnosis

Esophageal cancer is diagnosed by the following procedures:

1.Medical history and clinical examination: If the patient has symptoms of esophageal cancer, a proper medical and family history to identify the presence of risk factors should be taken.

2. Barium swallow test: This is the first test done when the patient complains of difficulty in swallowing. The patient is asked to swallow a thick liquid called barium which forms a lining in  the esophagus. X –ray is taken to detect any abnormal areas in the inner aspect of the esophagus. The advantage of this test is that it is used to detect even smaller lesions  and also the tracheo-esophageal fistula (a complication of this cancer that involves the trachea). But the disadvantage is that, it cannot detect the extent of the disease outside the esophagus.

3. Imaging techniques: The extent of the disease outside the esophagus, into the organs like the liver, and bones can be determined by imaging techniques like computed tomography, magnetic resonance imaging, and positron emission tomography. Sometimes CT scan will help even in biopsy procedures (CT-guided biopsy) if the tissue specimen to be collected is located very deep as the lesion is deeply situated inside the body.

4. Endoscopy:  An endoscope is a flexible, slim tube with a tiny video camera and light on the end and it is used to examine the inner aspect of the esophagus and the part of the stomach. Endoscopy-based tests and biopsies (endoscopy of the upper gastrointestinal tract) aid in the diagnosis of esophageal cancer or to ascertain the extent of its involvement to the adjacent structures.

5. Bronchoscopy, thoracoscopy, and laparoscopy: In these techniques, a flexible tube will be passed into the bronchi, chest, and abdomen respectively to determine the extent of esophageal cancer. These procedures are performed under general anesthesia.

6. Biopsy: A fragment of tissue will be removed and sent for histopathological examination. In advanced cases, this tissue specimen is tested for the presence of some proteins like HER-2, PD-L1, MMR, and MSI which plays a prominent role in the pathogenesis of esophageal cancer.

7. Routine investigations: The following investigations are done routinely in patients with esophageal cancer to know the immune status of the patient and to identify the presence of additional risk factors:

• Complete blood picture

• Tests to detect blood glucose levels

• Complete lipid profile

• Liver function tests (that detects the level of enzymes and proteins like  bilirubin, aspartate aminotransferase, alanine transaminase)

• Thyroid function tests

• Urine analysis

• Levels of vitamin B 12

Management

Treatment is best managed by a multidisciplinary team including surgeons, gastroenterologists, medical oncologists, radiologists, radiation oncologists, and pathologists. Factors that influence treatment decisions include the stage and cellular type of cancer along with the patient’s  general condition and any other co-morbid conditions associated with the disease. The different types of treatment for esophageal cancer are:

• Surgery : If the tumor size is small and is confined to the lining of the esophagus, it can be removed by mucosal resection(MS). But if the lesion is larger in size, partial or complete removal of the esophagus (esophagectomy) is advised. Esophagectomy can be performed in several ways. The type of surgery performed depends on the tumor features and location as well as the surgeon’s personal preferences. There is no proper evidence to suggest that which approach will give the best treatment outcome.

• Chemotherapy: It can be used before surgery (as neoadjuvant therapy), and after surgery (to reduce the risk of infection). The recommended regimen for EC is cisplatin for three weeks in combination with 5-fluorouracil (FU).

• Radiotherapy: It is advised before, during, or after chemotherapy or surgery.  In patients where surgery is contraindicated, it can be given as a single entity of treatment.

• Other approaches: Endoscopic mucosal resection (EMR) and mucosal ablation employing radiofrequency ablation, photodynamic therapy, Nd-YAG laser, or argon plasma coagulation have been employed as forms of endoscopic therapy for stage 0 and I illness in EC.

Management of esophageal cancer can be further divided into two phases:

• Local therapy: Treatments that target the tumor locally do not have a significant impact on the body as a whole. Although they might be utilized in other circumstances, these treatments are more likely to be beneficial for esophageal tumors that are in an earlier stage. Examples of local therapy are surgical therapy to remove the tumor, and radiation therapy to necrotize tumor cells.

• Systemic therapy: Drugs are used as systemic therapy and can be administered orally or intravenously. Several types of medications may be utilized, depending on the type of esophageal cancer. These include application of chemotherapeutic drugs like, fluorouracil, cisplatin, docetaxel, and epirubicin, immunotherapeutic drugs like with be like pembrolizumab, and nivolumab and targeted therapy with molecular inhibitors like trastuzumab.

With all these treatment methods, EC can be reduced to an extent, but cannot be completely cured. The prognosis for esophageal cancer is fairly poor because, by the time the first symptoms appear, the disease will progress to an advanced stage. The overall prognosis depends upon the stage of EC. So early diagnosis and prompt treatment are important to improve the survival rate in EC patients.