Esophageal Cancer: A Comprehensive Overview
The esophagus is one of the most commonly known organs. It is a long pipe-like fibromuscular muscle that is responsible for transporting enzymatically broken down round-shaped food (known as a bolus) from the mouth to the stomach. It is typically between 18-25 cm long. Because it is so prominent in the majority of the neck, there may be a certain susceptibility to cancer. Although esophageal cancer is on the rarer side of cancer, it can present devastating consequences, as it has only a 17.5% five year survival rate.
Esophageal cancer has been around for quite some time. The famous Hollywood legend Humphrey Bogart, pictured above, passed away from esophageal cancer almost 60 years ago. As a result of the advances in medicine, medical professionals have a clearer understanding of esophageal cancer, including its symptoms, classifications, diagnosis, treatment, and method of metastasis.
There are two main types of esophageal cancer, and are classified based on the point of origin. If the cancer originated in the “flat cells that line the esophagus”, then it is known as esophageal squamous cell carcinoma (ESCC). On the other hand, if the cancer begins in “cells that make and release mucus and other fluids”, then it is called esophageal adenocarcinoma (EAC). According to the World Cancer Report published by the World Health Organization (WHO), esophageal cancer is the eighth most common cancer in the world, whereby about half of all cases are diagnosed in China. According to the National Cancer Institute, EAC is the most common type of esophageal cancer in the United States and approximately 12,000 Americans were diagnosed with EAC in 2013. In addition, about 6,000 Americans were diagnosed with ESCC in 2013. It is interesting to note that the trend is opposite at the international level whereby ESCC is much more prevalent than EAC. This could be due to the risk factors of each.
According to Prabhu et al. in the American Journal of Gastroenterology, tobacco and alcohol are major risk factors for esophageal squamous cell carcinoma. The scientists' conclusion in their study was that the two have an even further detrimental effect when combined compared to individually. They stated that one of the two risk factors increases the likelihood of ESCC by 20-30% while both combined can increase the risk threefold. Therefore, the cause of ESCC is more environmental and lifestyle oriented in nature than EAC.
The primary risk factors for esophageal adenocarcinoma are acid reflux disease and obesity. According to Rutegard et al., EAC affects men significantly more than women, with about 70% of cases in men compared to 30% in women. The study stated that it stems from the more degrading nature of the esophagus due to acid reflux in men compared to women. Because EAC tends to affect the lower one-third of the esophagus leading into the stomach, this finding has great validity. Obese men tend to have a larger portion of fat distributed in the abdominal region compared to women. This explains the second risk factor of EAC since the lower esophagus leads into the stomach, and obesity is a risk factor for acid reflux disease. Acid reflux can cause an abnormal change in the cellular structure of the lower esophagus, known as Barrett’s esophagus. This condition is a precancerous form of EAC and therefore, patients suffering from Barrett's esophagus must be extremely careful.
Given this wealth of information, it is evident that the widespread prevalence of EAC as opposed to ESCC in the United States is due to the obesity epidemic. Moreover, the reverse trend observed internationally could potentially be due to the more widespread practice of cigarette smoking abroad compared to the United States.
According to the 2013 Ferri's Clinical Advisor, the primary symptom of esophageal cancer is pain and difficulty in swallowing. However, in many cases, the cancer has spread throughout the esophageal tube at the point of diagnosis and the likelihood of metastasis is higher. According to Pennathur et al., “weight loss is often a symptom in ESCC but not usually in cases of EAC.” It is can be implied that Humphrey Bogart most likely died from esophageal squamous cell carcinoma because he was a heavy cigarette smoker, and by his death, he weighted 80 lbs.
As the esophageal cancer deteriorates, functions of the esophagus become much more difficult. According to the 18th edition of Harrison's Principles in Internal Medicine, these severe symptoms include: “nausea, vomiting, regurgitating of food, and coughing”. This is due to difficulty of peristalsis, which is defined as the involuntary movement of esophageal muscles that push food down the esophagus. The best way to diagnose esophageal cancer with certainty is via an endoscopy. Individuals who have a family history of cancer should consult their gastroenterologist to determine the best course of action.
Upon diagnosis, treatment options can vary. First, adequate nutrition is paramount because patients with esophageal cancer tend to have difficulty swallowing. Second, as with most cancers, it depends on the localization of the tumor coupled with its incidence of metastasis. If the cancer has been detected early, then a multidisciplinary approach involving surgery, radiotherapy, and/or chemotherapy may be used. Esophagectomy (complete or partial surgical removal of the esophagus) can be difficult, and thus the optimum choices depending on severity is still under discussion by the scientific/medical community.
As is the case with the majority of cancers, early detection is key. Although esophageal cancer isn't the most common type of cancer, it can be fatal if it metastasizes. This is due to the anatomy, as it is directly posterior (behind) to the larynx. In addition, the esophagus runs through the thoracic cavity. Therefore, because of the location of the esophagus, the aggressive forms of esophageal cancer have great potential to spread to these vital areas, causing head/neck cancer and lung cancer. Moreover, there are lymph nodes dispersed throughout the neck, which increases the different avenues by which the cancer spreads (see my TNM recnac article for more details).
Overall, the best way to prevent esophageal is to make lifestyle changes. Quitting inhalation smoking/chewing tobacco will greatly reduce the risk. In addition, the National Cancer Institute has noted that cabbage family vegetables (broccoli, cauliflower, brussel sprouts, cabbage), green and yellow vegetables in general, and fruit may decrease the risk of esophageal cancer. It is critical that esophageal cancer is detected early, because it's poor prognosis is due in large part to a late diagnosis. If you or a loved one are at risk, please consult your gastroenterologist to decide on the best course of action. Most importantly, implementing the simple lifestyle changes aforementioned can make a significant difference.
About SC Ali
S.C. Ali is an author/editor. He has a degree in Chemistry, and is interested in the study and practice of medicine. His blog can be found here: http://thebronzelifestyle.com/