What is esophageal cancer?
The esophagus is the muscular tube that connects the mouth and throat with the stomach. There are two major kinds of cancer of the esophagus. The first, squamous cell carcinoma, has, in the past, been the most common type. It still remains the most common form of this cancer in many parts of the world. It is also associated with tobacco and alcohol abuse, some nutritional deficiencies, ongoing esophageal injury, and certain dietary irritants. Cancers of the proximal esophagus, the part of the esophagus in the upper chest and neck, are almost exclusively squamous cell carcinoma, although in general this cancer tends to develop in the lower esophagus.
The second kind of esophageal cancer is adenocarcinoma. Thirty years ago, this was an uncommon illness. It has now overtaken squamous cell carcinoma as the most common form of this disease in North America. Its incidence is increasing at a rate faster than any other malignancy in the United States. It is much less commonly associated with tobacco or alcohol abuse, and it is a disease that tends to develop most frequently in middle aged and older Caucasian males.
The only known predisposing factor is an esophageal condition called Barrett's esophagus, a change in the esophagus that arises in some patients with chronic gastroesophageal reflux disease (GERD). It should be stressed, however, that only a small minority of those patients with symptoms of reflux esophagitis will develop Barrett's esophagus, and only a small minority of patients with Barrett's esophagus will develop adenocarcinoma. However, the identification of Barrett's esophagus in a patient is an indication for routine endoscopic screening in an effort to identify the early development of an esophageal cancer. There is no clear explanation as to why this disease has increased in frequency over the past 30 years, and why this demographic distribution exists.
What are the symptoms of esophageal cancer?
Difficulty swallowing, or dysphagia, is the most common symptom of cancer of the esophagus. Patients may also note pain upon swallowing, and the need to alter the kinds of food they are eating. Early satiety, a feeling of fullness after a smaller than normal meal, and an increase in belching or regurgitation are also not uncommon symptoms. Unfortunately, however, the development of symptoms like dysphagia is usually associated with a locally advanced cancer. Early cancers are rarely symptomatic.
How is esophageal cancer diagnosed?
Difficulty swallowing should not be ignored, and merits further evaluation, particularly in the high-risk populations noted above. A barium swallow (an X-ray scan of the upper gastrointestinal tract) can suggest the diagnosis, but an upper endoscopy (when a scope with a tiny camera is advanced through the esophagus) has proven to be the most useful test. This test allows the physician to see any abnormality in the lining of the esophagus, and to biopsy the lesion (take a small sample of the tissue). Most of these cancers occur in the lower esophagus or at the junction between the esophagus and the stomach.
Once the diagnosis has been made, the disease extent needs to be assessed. The local spread of the tumor and lymph node or regional involvement can be difficult to accurately determine. However, with current computerized tomography (CT), positron emission tomography (PET) scans, and endoscopic ultrasound techniques, an assessment of local, regional and distant disease spread can be made. Although squamous cell carcinoma does not tend to spread to other organs until late in its natural history, adenocarcinoma is more commonly widespread at diagnosis.
What are the cancer treatment options for esophageal cancer?
In patients with early stage disease, the optimal cancer treatment approach is surgery. Although an esophagectomy (removal of the esophagus) is a major operation and may not be an appropriate cancer treatment in elderly or debilitated patients, it is associated with an excellent cure rate in patients with early stage disease.
Unfortunately, most patients present with either locally or regionally advanced cancer. In this situation, surgery as a single form of cancer treatment is not satisfactory. Multi-modality approaches to cancer treatment using surgery, radiation and chemotherapy have been recommended instead and can result in cure in a percentage of patients. Radiation therapy by itself has been relatively unsuccessful, but when combined with chemotherapy, it has been curative. Whether the use of surgery in conjunction with radiation and chemotherapy can further improve the results is still being investigated. Other patients, unexpectedly found to have more advanced disease at the time of their surgery, will benefit from post-operative, or adjuvant, chemotherapy and radiation.
In patients with widespread, incurable cancer, single-modality chemotherapy and/or radiation therapy can provide significant symptomatic relief. There are also a number of endoscopic techniques available for cancer treatment that can successfully address the swallowing problems for those with locally advanced cancer. Endoscopic stent placement, photodynamic therapy, laser photoablation, and esophageal dilatation have all been used in this situation.
Clinical trials in esophageal cancer are available, and have allowed us to make significant progress in our understanding of how best to manage this cancer, as well as cancer treatment. These trials include newer combinations of chemotherapy, radiation therapy, and surgery, as well as the use of the newer, targeted agents directed against specific molecular targets in cancer cells in cancer treatment.