The gastrointestinal tract (GIT) comprises several organs that digest and absorb food and excrete waste metabolites. The gastrointestinal tract comprises the esophagus, stomach, small intestine, large intestine, colon, rectum, and anus. Other organs that help digest food include the liver and pancreas.
Different GIT organs have different types of cells, including mucus-secreting cells, glandular cells, neuroendocrine cells, and epithelial cells, and these play a pivotal role in the optimum functioning of the different gastrointestinal tract organs.
Due to mutations in one or more cells of the gastrointestinal tract, the cells divide without any control, resulting in the formation of a tumor. If not diagnosed and treated early, the tumor may spread to other organs of the gastrointestinal tract, lymph nodes, or nearby and distant organs, such as the lungs or bones.
Primary GIT cancer starts in the GIT, while metastatic GIT cancer forms in other organs and spreads to one or more organs of the GIT.
Gastrointestinal carcinoma is one of the most common cancers. Despite the advancements in the diagnosis and management of GIT cancer, it is still one of the most common reasons for cancer-related deaths. Different types of gastrointestinal tumors have different incidence rates. Although there are reports of a reduction in the incidence of some types of gastrointestinal cancers, these cancers pose a healthcare challenge.
Based on the organs that they arise from, GI cancers are categorized into various types. The following are the different types of gastrointestinal tumors:
Colorectal cancer is the term used for colon and rectal cancer. Based on the initiation site, these cancers may be subdivided into colon or rectal cancers. The early stage of colorectal cancer is the presence of polyps in the rectum or colon.
The esophagus is a long tube carrying food from the oral cavity to the stomach. Esophageal cancer in most patients is diagnosed at an advanced stage as it does not cause symptoms or the symptoms overlap with other common conditions.
Stomach or gastric cancer starts in the stomach. The cancer may develop in any part of the stomach. Although there has been a significant reduction in the incidence of stomach cancer in the past couple of decades, it is still one of the most common cancers.
The pancreas is an organ located behind the stomach that assists digestion by releasing pancreatic fluid. It also releases hormones that regulate blood sugar. Uncontrolled growth of pancreatic cells results in pancreatic cancer.
The anal canal is situated at the end of the rectum, through which the stool or fecal matter is excreted from the body. Anal cancer occurs due to the uncontrolled division and proliferation of anal cells. Patients with anal cancer present with anal pain, itching, and rectal bleeding.
The liver is the body's largest internal organ and performs several essential functions. Various types of cells are present in the liver. Uncontrolled division and proliferation of one or more of these cells result in liver cancer.
The development of malignant cells in the small intestine results in small intestinal cancer. The condition is also called small bowel cancer. Small intestinal cancer is uncommon and constitutes about 3% of all gastrointestinal cancers.
Gastrointestinal cancer staging is done to evaluate the extent of the disease’s spread. The staging parameters may slightly vary for different types of gastrointestinal cancer. In general, the following are the important gastrointestinal cancer stages:
It is known as carcinoma in situ. This stage suggests the presence of abnormal cells on the mucosal layer. These cells can potentially develop into cancer and spread to nearby healthy tissues.
This stage is categorized into stages IA and IB. In stage IA, the cancer develops in the mucosa and may have spread to the submucosa. In stage IB, cancer has developed in the mucosa and invaded the muscle tissues; in stage; OR cancer has developed into the mucosa, spread to the submucosa, and invaded 1–2 nearby lymph nodes.
This stage is categorized into stages IA and IB. In stage IA, the cancer develops in the mucosa and may have spread to the submucosa. In stage IB, cancer has developed in the mucosa and invaded the muscle tissues; in stage; OR cancer has developed into the mucosa, spread to the submucosa, and invaded 1–2 nearby lymph nodes.
In stage IIA, the cancer cells invade the submucosa and 3 to 6 nearby lymph nodes; OR cancer affects the muscle layer, and 1 to 2 nearby lymph nodes; OR cancer invades the subserosa. In stage IIB, cancer cells invade the submucosa and 7 to 15 nearby lymph nodes; OR cancer affects the muscle layer, and 3 to 6 nearby lymph nodes; OR cancer invades the serosa.
In stage IIIA, the muscle layer is invaded along with 7 to 15 nearby lymph nodes; OR subserosa and 3 to 6 nearby lymph nodes; OR serosa and 1 to 6 nearby lymph nodes; OR cancer spreads to surrounding organs, such as the diaphragm, liver, and pancreas. In stage IIIB, cancer invades the muscle layer and 16 or more nearby lymph nodes; OR serosa or submucosa and 7 to 15 nearby lymph nodes; OR nearby organs; and 1 to 6 nearby lymph nodes. In stage IIIC, cancer spreads to the serosa or subserosa and ≥16 nearby lymph nodes; OR surrounding organs and seven or more nearby lymph nodes.
Gastrointestinal cancer stage 4 is also known as advanced or metastatic cancer. In this stage, cancer metastasizes to distant organs, such as the liver, lungs, and distant lymph nodes.
The signs and symptoms of GI cancer often vary from one patient to another. Each type of GI cancer may have different sets of symptoms. Becoming aware of the different gastrointestinal cancer symptoms and the possible causes is important, as it helps one seek the right care at the right time.
The exact cause of GI cancer is unknown; however, certain lifestyle-related and non-lifestyle-related factors have been found to increase the risk of GI cancer.
Different types of GI cancer may have different sets of gastrointestinal symptoms and causes. Those with poor diet habits, such as a heavy intake of processed foods and a low intake of fruits and vegetables; those who smoke; those with H. pylori infection; and those with chronic gastritis, have a higher risk of stomach cancer.
Esophageal cancer risk is high among those who have chronic gastroesophageal reflux disease, underlying medical conditions such as obesity, Barrett's esophagus, and bile acid reflux, who drink alcohol, and who have a history of radiation therapy in the chest.
Colon cancer risk is high among those with a history of colon polyps, inflammatory bowel disease, and inherited syndromes, such as Lynch syndrome, an unhealthy lifestyle, obesity, and excessive alcohol intake.
Liver cancer risk is high among those with underlying medical conditions, such as chronic hepatitis infection, diabetes, cirrhosis, non-alcoholic fatty liver disease, inherited liver diseases (Wilson's disease and hemochromatosis), aflatoxin exposures, and excessive consumption of alcohol.
Almost half of the carcinoid tumors occur in the GIT. Melanomas of the GIT are usually asymptomatic but may cause symptoms in some cases. Common signs of intestinal leiomyosarcomas include GI bleeding and abdominal pain.
Not all patients experience the same gastrointestinal cancer symptoms. Some may not experience any early signs, while others do. Also, these symptoms may vary depending on the type of GI cancer. In general, the following are the important gastrointestinal cancer symptoms:
Abdominal pain is one of the most common gastrointestinal cancer symptoms. Abdominal pain due to cancer may be persistent and may not go away with medication. Although there may be multiple other reasons for abdominal pain, it should be diligently evaluated to rule out severe conditions.
Nausea is one of the early signs of gastrointestinal cancer. It may occur due to obstruction of food, liquid, or gas by the tumor. The block may also result in constipation, bloating, and abdominal cramps.
Vomiting is another symptom of gastrointestinal cancer. It may be due to obstruction in stomach cancer and prolonged constipation due to colorectal cancer. Vomiting may also be the result of gastrointestinal cancer treatment.
Gastrointestinal cancer may also result in a reduced appetite. There are several reasons for reduced appetite, including physical and psychological reasons. Physical causes include indigestion, abdominal pain, and constipation. Psychological reasons include depression and stress. For a proper evaluation of the actual cause of loss of appetite, it is important to consult a specialist.
Patients with gastrointestinal cancer, especially stomach and esophageal cancer, may experience heartburn due to acid reflux. Heartburn may also be the result of gastrointestinal cancer treatment.
Loss of appetite, indigestion, stress, and depression result in weight loss. It has been reported that almost 80% of patients with esophageal cancer, pancreatic cancer, and stomach cancer lose considerable weight before diagnosis.
Black stools or fresh blood in the stools are one of the signs of gastrointestinal cancer. Fresh, bright red blood may indicate anal or colorectal cancer, while black, tarry stools may suggest stomach cancer.
Patients with gastrointestinal cancer have prolonged indigestion and burping. Patients experience sickness, bloating, abdominal discomfort, and heartburn due to indigestion.
Some of the possible causes of gastrointestinal cancers are:
Age plays a vital role in the development of gastrointestinal cancer. For instance, stomach cancer most commonly occurs in people aged between 50 and 70 years. The average diagnosis age of colon cancer is 72 years in women and 68 years in men.
Having a family history of gastrointestinal cancer is an important risk factor for GI cancer. An association between the family history of stomach and esophageal cancer and the development of upper gastrointestinal cancer has been reported.
Patients with IBD are at increased risk of developing colorectal cancer. It is due to prolonged inflammation of the bowel and longer immunosuppressive drug exposure.
Unhealthy dietary habits may also cause gastrointestinal cancer. Excessive consumption of processed or red meat may cause gastrointestinal cancer. Further, thermal irritation due to hot beverages may also cause esophageal cancer.
Obesity may also cause gastrointestinal cancer. The mechanisms of this association include chronic low-grade inflammation due to obesity, altered insulin signaling, and an alteration in the metabolism of sex hormones.
Prolonged use of tobacco may be the reason for gastrointestinal cancer. It has been reported that about one-fifth of cases of gastrointestinal cancer and about one-fifth of deaths due to gastrointestinal cancer are linked to smoking.
Excessive alcohol consumption increases the risk of gastrointestinal cancer and liver cancer. Gastrointestinal cancer due to alcohol consumption is probably due to the formation of acetaldehyde (the primary metabolite of alcohol), resulting in local toxicity in the stomach.
Viral infections are also associated with gastrointestinal cancer. Studies reported a link between disease with the Epstein–Barr virus and gastric cancer. There is also an association between chronic hepatitis infection and liver cancer.
Unhealthy lifestyles, such as poor diet, lack of physical activity, and stress, may cause gastrointestinal cancer. Other factors that may cause gastrointestinal cancers are excessive alcohol consumption, smoking, and low socio-economic status.
Helicobacter pylori has a contrasting effect on different types of gastrointestinal cancers. Studies have found that H.pylori infection may increase the risk of gastric cancer and colorectal cancer. However, the risk of esophageal adenocarcinoma may be reduced in people with this infection.
People should visit an oncologist if they experience nausea, vomiting, loss of appetite, abdominal discomfort, blood in stools, sudden changes in bowel habits, constipation, diarrhea, heartburn, and unexplained weight loss.
The diagnosis of gastrointestinal cancer begins with a physical examination and a medical history assessment. If the findings from these are alarming, further tests may be recommended. Upon arriving at a conclusive diagnosis and staging the cancer, personalized care plans are devised, which are going to treat the disease effectively and help patients return to the best state of health possible.
Since many of the symptoms of GI cancer overlap with those of other less serious GI conditions, doctors will initially perform a physical examination to understand the causes of the symptoms. The following are the most commonly recommended tests for gastrointestinal cancer diagnosis:
The doctor performs a detailed physical examination of the patients and discusses their symptoms. The doctor also asks the patient about the symptoms' initiation, progression, and severity.
The patient's medical history is also an important consideration when evaluating the possibility of gastrointestinal cancer. Certain conditions, such as obesity, diabetes, inflammatory bowel disease, and certain inherited conditions, increase the risk of gastrointestinal cancer. A family history of gastrointestinal cancer also increases the risk of this condition.
If the results of the physical examination and medical history assessment are found to be alarming, that patient is advised to undergo further tests.
Several imaging tests are recommended for gastrointestinal cancer diagnosis. These include ultrasound, computed tomography, magnetic resonance imaging, and positron emission tomography. Along with the diagnosis, imaging tests are also recommended for GI cancer staging, treatment planning, monitoring, and relapse evaluation.
Ultrasound is an important technique for detecting gastrointestinal tumors and is combined with traditional endoscopic methods. Advanced ultrasound techniques help evaluate the gastrointestinal walls and assist oncologists in detecting surrounding metastases.
Computed tomography, or CT scan, helps detect the lesions in the gastrointestinal tract and allows the staging of the disease.
Magnetic resonance imaging, or MRI, provides detailed and high-quality images of the gastrointestinal tract by using radio waves and magnetic fields.
Positron emission tomography, or PET scan, uses radioactive glucose derivatives. This technique provides detailed information about cancer metastasis by scanning the body.
Blood tests for certain tumor markers may be recommended during a gastrointestinal cancer diagnosis. Elevation in the levels of certain markers may indicate the presence of GI cancer. That said, other medical conditions can also cause the levels of these biomarkers to increase, and therefore, blood tests alone cannot be used to diagnose GI cancer.
Blood tests are also used to obtain vital information about the body's overall health and the functioning of the kidneys and liver. Liver function tests are important to determine the spread of cancer to the liver. In patients with colon cancer, blood tests may detect anemia, as there may be frequent blood loss in colon and rectal cancer.
The barium swallow method is used for detecting abnormalities in various gastrointestinal tract organs, such as the esophagus, stomach, colon, and rectum. The test involves the oral administration of barium. Barium is a white liquid that outlines the abnormal tissues in the gastrointestinal tract. After administering barium liquid, the patient undergoes a series of X-ray scans to obtain images of the gastrointestinal tract. The upper GI tract evaluation is called the upper GI series, and the lower GI is evaluated through the lower GI series.
Upper endoscopy is also known as endoscopic gastroduodenoscopy. It helps determine the presence of cancer in the esophagus, stomach, and upper small intestine regions. The techniques use an endoscope, which is a thin, long tube with a camera at the end. The procedure is performed under sedation. The images are displayed on the screen. The doctor examines various parts of the upper GI tract for the presence of cancer.
Lower endoscopy is also known as colonoscopy. A colonoscopy is used to detect abnormalities in the colon. The colon is the initial and longest section of the large intestine. The procedure is performed with the help of a colonoscope, which is a thin, elongated tube with a light and camera source. A colonoscopy is recommended to examine the colon completely for the presence of polyps or lesions. This procedure may be performed under sedation or anesthesia. The doctor may also obtain the tissue sample for further examination if any abnormal tissue is detected.
EUS is a non-invasive method used to detect cancer of the gastrointestinal tract. It involves the use of an endoscope and ultrasound. It not only provides images of the GIT but also of the nearby organs, such as the pancreas, liver, lymph nodes, gallbladder, and lungs.
A biopsy is a method that involves obtaining a sample of abnormal tissues and sending it to the laboratory for further examination. A biopsy may be done through different procedures. It includes a biopsy through colonoscopy or endoscopic ultrasound. During endoscopic ultrasound, the endoscope has small needles to collect samples of abnormal tissues. A biopsy often helps in arriving at a conclusive diagnosis.
Gastrointestinal cancer treatment often involves a comprehensive approach, wherein a multidisciplinary team carefully goes through the case information and takes the patient’s overall health condition into consideration before devising a personalized treatment plan. The following are the commonly recommended approaches for gastrointestinal cancer treatment:
Different types of surgical interventions are available for treating different gastrointestinal cancers. As a GI cancer treatment, surgery involves the removal of the tumor along with a small portion of healthy tissue. Depending on the case, the specialists may also recommend partial or complete removal of the cancer-affected organ.
Cancer surgery for GI cancer is often recommended along with other treatment approaches like chemotherapy, radiation therapy, immunotherapy, and targeted therapy. The following are the different surgical procedures recommended for different types of gastrointestinal cancers.
Surgical techniques for esophageal cancer include partial and total esophagectomy. Techniques for esophagectomy include open surgery and minimally invasive esophagectomy.
Stomach cancer surgeries include endoscopic resection, endoscopic submucosal dissection, gastrojejunostomy, endoluminal stent placement, partial gastrectomy (proximal or distal gastrectomy), total gastrectomy, laparoscopic gastrectomy, and robotic-assisted laparoscopic gastrectomy.
Surgical interventions for colon cancer include local excision, polypectomy, colectomy, and colostomy. The techniques used for performing colectomy include open colectomy and laparoscopic-assisted colectomy.
Surgery is also effective in managing gastrointestinal stromal tumors.
If the doctor suspects the cancer’s spread to the surrounding lymph nodes, lymph node dissection may be performed along with the main surgery. The lymph nodes are examined for the presence of cancer cells. It helps in determining the stage of cancer. Cancer in the lymph nodes suggests the progression of cancer. In such cases, the gastrointestinal cancer treatment strategy may include other treatments like chemotherapy or radiation therapy along with surgery.
Palliative care is recommended for advanced-stage GI cancers. Palliative care aims to manage cancer symptoms to improve the patient's quality of life. In patients with esophageal and stomach cancer, palliative surgery helps prevent bleeding from the tumor and avoids obstruction in the esophagus and stomach due to tumor growth.
Chemotherapy is one of the GI cancer treatment approaches. It involves the oral or injectable administration of anti-cancer drugs that kill the cancer cells. These drugs interfere with the vital cellular pathways of cancer cells and stop them from growing further. These drugs destroy cancer cells throughout the body. Thus, the patients experience several systemic side effects, like vomiting, loss of appetite, nausea, and hair loss. Chemotherapy may be used in combination with surgery and/or radiation therapy.
Radiation therapy is another important GI cancer treatment approach, wherein high-energy radiation beams are used to kill cancer cells. The technique is used in combination with surgery and/or chemotherapy. Radiation therapy for gastrointestinal cancer is usually delivered through external beam radiation therapy, wherein the tumor is targeted with an external radiation source, a linear accelerator. It may be used before the surgery to shrink the tumor size or after the surgery to kill the remaining cancer cells.
Immunotherapy is an advanced option for GI cancer treatment. It works by enhancing the ability of the immune system to identify and attack cancer cells in the body. Cancer cells use numerous molecular mechanisms to hide themselves from the immune system. Immunotherapy drugs block these mechanisms and allow the immune system to identify and attack the cancer cells. Immunotherapy is usually used in cases of non-response to traditional therapies or in advanced gastrointestinal cancers. In some cases of stomach cancer, a combination of immunotherapy and chemotherapy is recommended.
Some proteins, genes, or tissue environments enhance the growth of cancer cells and their proliferation. Targeted therapy interferes with the working of these genes and proteins and prevents the cell division and proliferation of cancer cells. Before recommending this GI cancer treatment, the oncologists comprehensively evaluate the cytology of the cancer cells to identify the cancer-specific genes and proteins.
HCG Cancer Hospital is an advanced and highly sophisticated institute for managing all gastrointestinal cancers, such as esophageal, stomach, colorectal, and anal cancers. The center has ultra-modern diagnostic facilities to differentiate between cancer and other underlying medical conditions. Further, the center has the facilities to perform all types of cancer-related surgeries to improve outcomes. The facilities for radiation therapy, immunotherapy, chemotherapy, and targeted therapy are also available at the center.
Over the years, researchers have been able to identify multiple factors that can impact one’s risk of developing gastrointestinal cancer. Some of these factors are modifiable, while others are not. Having these risk factors does not guarantee a GI cancer diagnosis; however, it only increases one’s chance of developing it.
It is possible to reduce the risk of GI cancer by following certain preventive measures, which often involve adopting specific lifestyle modifications.
Some of the most common gastrointestinal cancer risk factors include:
Although cancer may occur at any age, people between the ages of 50 and 70 are at higher risk for stomach cancer. Similarly, esophageal cancer most frequently occurs in people between 45 and 70 years old. However, there is data to indicate that people below 50 years of age are more frequently diagnosed with esophageal adenocarcinoma. In the case of colon cancer, the average diagnosis age in women is 72 and 68 in men. Colon cancer is more common in people over 50 years of age.
Gender also plays an important role in the development of gastrointestinal cancer. It has been reported that men have a 2-fold higher risk for stomach cancer than women. One of the reasons for this is the presence of estrogen in women, which has a protective effect against H. pylori infection (a common risk factor for stomach cancer). In the case of esophageal cancer, men have an almost 4–5 times greater risk than women. Men are at greater risk of developing colon cancer than women. Further, it has been found that right-sided colon cancer is more likely to occur in women than men.
The medical history of the patients also affects the risk of gastrointestinal cancer. Patients with underlying medical conditions, such as gastroesophageal reflux disease, gastritis, and H. pylori infection, have an increased risk of stomach cancer. Gastroesophageal reflux disease, history of neck and head cancer, Barrett’s esophagus, obesity, and HPV infection increase the risk of esophageal cancer. Obesity, smoking, and inflammatory conditions of the colon increase the risk of colon cancer.
A family history of gastrointestinal cancer also increases the risk of this condition. The presence of esophageal, stomach, or colon cancer in immediate relatives, such as a brother or father, increases the risk of these conditions. Further, hereditary diseases, such as Lynch syndrome, Peutz-Jeghers syndrome, juvenile polyposis syndrome, and familial adenomatous polyposis in the family, also increase the risk of gastrointestinal cancers.
Diet also plays a major role in the development of gastrointestinal cancer due to the direct effect of food on the tissues of the GIT organs. A diet rich in salty and smoked foods and high-saturated fats increases the risk of stomach cancer. Excessive consumption of refined starches and red meat increases the risk of colorectal cancer.
People who are overweight or obese are more likely to have a higher risk of developing various types of gastrointestinal cancers, including esophageal, stomach, colon, rectum, and anal cancers. It may probably be due to chronic mild inflammation and altered insulin signaling that are caused by obesity.
There is an association between smoking and the development of gastrointestinal cancers. It has also been reported that alcohol increases the carcinogenic effect of smoking.
Chronic inflammatory conditions of the esophagus, stomach, and large intestine increase the risk of gastrointestinal cancer. People with inflammatory bowel diseases have a higher risk of developing colorectal cancer.
Some of the measures to prevent gastrointestinal cancer are:
Food rich in fruits, vegetables, proteins, and calories lowers the risk of gastrointestinal cancer. It is important to incorporate high-fiber foods, such as apples, Brussels sprouts, and beans, to lower the risk of GIT cancer.
Regular physical activity significantly lowers the risk of gastrointestinal cancer, especially in people with a high cancer risk. Physical activity lowers the other risk factors. It maintains a healthy weight and reduces psychological stress. Further, it also reduces the body's overall inflammatory status, thereby reducing the overall risk of GI cancer.
Quitting tobacco lowers the risk of several cancers and gastrointestinal cancers, including stomach, colon, and rectal cancers. It also reduces the likelihood of esophageal and oral cancers. Avoiding tobacco use helps prevent inflammation, maintain appropriate immune function, and limit toxic exposure to body tissues.
Limiting the consumption of alcohol also lowers the risk of GI cancer. It reduces the production of acetaldehyde, which has a toxic effect on the GI tissues.
The presence of polyps in the stomach and large intestine increases the risk of colorectal cancer. It is important to detect and remove these polyps to lower the likelihood of GI cancer. Opting for regular screening and proper evaluation of persistent GI symptoms can support early detection and timely treatment for GI cancers.
Certain medications, such as proton pump inhibitors, are known to increase the risk of GI cancer. Avoiding these medications may help prevent GI cancer.
Several factors increase the risk of gastrointestinal cancer. These GI cancer risk factors include older age, underlying conditions such as obesity, inflammatory bowel disease, genetic syndromes, family history of cancer, medical history, poor and unhealthy diet, smoking, and excessive alcohol consumption.
Gastrointestinal cancer develops in the gastrointestinal tract, which includes the esophagus, small intestine, stomach, large intestine, colon, rectum, and anus. It also includes cancers of the liver and pancreas. The staging of gastrointestinal cancer is done to understand how far the disease has spread. Stages I and II refer to the early stages of GI cancer, whereas stage IV is the most advanced stage of gastrointestinal cancer.
