Gastrointestinal cancer is cancer that affects the organs in the digestive system
including the esophagus, stomach, pancreas, gallbladder, liver, small and large intestine, anus and rectum. Gastrointestinal cancer is characterized by the uncontrolled growth of normal cells that make up the digestive tract.
The exact cause of gastrointestinal cancer is not clear. However, certain risk factors such as excessive alcohol intake, smoking, advanced age, diet rich in animal fat and salt, poorly preserved food and obesity may increase your risk of developing gastrointestinal cancer.
Gastrointestinal cancer significantly impacts your quality of life. It not only affects you physically, but also emotionally. Pain, fatigue, stress and the side effects of treatment become a part of your life.
The gastrointestinal system is a long tube running right through the body, with specialized sections that are capable of digesting and extracting useful components entering the mouth and expelling waste products from the anus. Once food has been chewed and mixed with saliva in the mouth, it is swallowed and passes down the esophagus (food pipe), a long, narrow tube. The food pipe is lined by muscles that expand and contract, pushing food into the stomach.
The stomach secretes acid and other digestive enzymes for digestion and stores food before it enters the intestine. The liver is the main organ of metabolism and energy production. It produces bile, which is stored in the gallbladder, and also stores iron, vitamins and trace elements. The pancreas, located behind the stomach, produces enzymes and hormones that aid in digestion and metabolism. Once food has been mulched and partially digested by the stomach, it is pushed into the duodenum (first part of the small intestine). Secretions of the gallbladder and pancreas empty into the small intestine, the site where most of the chemical and mechanical digestion and virtually all of the absorption of useful materials takes place. The large intestine is the last part of the digestive tube and the location of the terminal phases of digestion, where waste is processed and stored in the rectum, and excreted through the anus.
Symptoms of gastrointestinal cancer may include abdominal pain, discomfort or tenderness, change in shape, frequency or consistency of bowels, blood in stool, bloating, vomiting, nausea, fatigue, loss of appetite and unintentional weight loss.
Your doctor diagnoses gastrointestinal cancer by performing a thorough physical examination and reviewing your medical history. Certain tests may be ordered to assist and confirm the diagnosis, which includes:
- Blood tests: The tests include full blood count and tumor marker tests.
- Upper endoscopy: Upper endoscopy is a procedure in which a long, thin flexible tube with a tiny camera is passed through your mouth and down your throat to examine the lining of the esophagus, stomach and duodenum.
- Fecal test: Fecal samples are examined under the microscope for abnormalities.
- Barium swallow: You are given a liquid that contains barium to swallow. X-ray imaging can detect this barium, which coats the walls of the esophagus and stomach, making abnormalities visible more clearly.
- Biopsy: A small sample of tissue is removed and examined under the microscope for abnormal cells.
- Colonoscopy: A colonoscope, a long narrow tube with a camera is inserted from the rectum to examine your colon.
These tests help identify the location and stage (stage 0 to stage 4, in order of severity) of cancer, which is important for designing the treatment plan.
Treatment depends on the stage of the cancer, location, your age and general health. Several treatment options are available for treating gastrointestinal cancers. The standard approaches include surgery, radiation therapy, chemotherapy and target therapy.
- Surgical procedures vary depending upon the size and site of the cancer. Some of the common surgeries include:
- Fulguration: use of electric current to kill tumor cells
- Cryosurgery: involves freezing the cancer cells to destroy them
- Resection: removal of the cancerous growth
- Radio frequency ablation: use of high energy radio waves to kill cancer cells
- Radiation therapy is a procedure where high-energy rays are targeted at the cancer cells to destroy them.
- Chemotherapy involves the use of anti-cancer drugs given intravenously (through the veins) or orally (by mouth). This type of treatment is extremely useful in cases where the cancer has spread to different parts of the body. These drugs work against the cells that divide quickly; thereby, slowing down the growth of cancer.
- Target therapy stops new blood vessels from developing in the cancer cells. With no blood supply, the growth of cancer cells slows down.
The outcome of treatment varies from person to person. Treatment in some cases can make you free of cancer, while in others, it is given to slow down the progression of the cancer and add to your days of living. The factors that can affect your prognosis include the location, stage and type of cancer, your age, health before cancer, and your response to treatment.
If left untreated, cancer usually spreads to other areas of the body, eventually leading to death.
Surgery for gastrointestinal cancers is indicated for stages 0, I, II and III cancers and surgical removal is considered the primary treatment for cancer. It involves the complete removal of the primary tumor along with a margin of healthy tissue to ensure that there are no residual cancer cells. The surgical procedure depends to a large degree on the spread of cancer through the tract wall, to other organs or to the lymph nodes. If infected, lymph nodes and adjoining organs are removed along with the gastrointestinal cancer. In some cases, surgery is combined with radiotherapy or chemotherapy.
Gastrointestinal cancer surgeries are performed under general anesthesia. Some of the common surgeries are mentioned below.
Total esophagectomy or esophagectomy
Esophageal cancer surgery aims at treating cancer by surgically removing the whole (total esophagectomy) or part of the esophagus (esophagectomy) and the surrounding tissue that is affected. The remaining esophagus is then reattached to the stomach. Surgery for esophageal cancer can be performed by either an open approach or a minimally invasive approach using laparoscopy.
Gastrectomy is the removal of the stomach to treat gastric cancer. It can be carried out through subtotal gastrectomy, where only a part of the stomach is removed, or total or radical gastrectomy, where the whole stomach is freed from the surrounding tissue, cut and carefully removed. The remaining part of the stomach is reattached or in case of total gastrectomy, the esophagus is connected to the small intestine.
Pancreatectomy is the removal of the entire or part of the pancreas. There are many types of pancreatectomy. Also known as pancreaticoduodenectomy, the Whipple procedure involves the removal of the head (wide part) of the pancreas along with parts of the gallbladder, small intestine, bile duct, and sometimes a part of the stomach. The remaining structures are reconnected so that enzymes and bile can flow normally into the intestine. Distal pancreatectomy is usually performed when cancer is found in the middle or tapering end of the pancreas. Total pancreatectomy or complete resection is opted for when the tumor extends across the pancreas.
Cholecystectomy is surgery to treat cancers of the gallbladder. The procedure may also involve the removal of parts of other neighboring organs such as the liver, common bile duct, pancreas, small intestine and/or lymph nodes.
Hepatectomy is surgery to remove the liver along with some of the healthy tissue around it. It may involve the excision of only a part or the whole liver, in which case a healthy liver is transplanted to replace the diseased one.
The endoscopic mucosal resection (EMR) procedure is indicated to treat gastrointestinal cancer that has spread to the lining of the tract. Your surgeon inserts an endoscope (a thin long tube with a light source and camera) through the mouth to the cancerous growth present in the esophagus, stomach or upper small intestine. Cancers in the colon are reached by an endoscope inserted through the anus. Surgical tools are passed through the EMR to remove the cancerous tissue. The surgery is non-invasive as it does not involve any cuts on the body.
Abdominoperineal resection is a surgical procedure that involves the removal of the lower end of the large bowel i.e., colon, rectum or anus. The surgery is indicated for the treatment of anal cancer and rectal cancer. Abdominal perineal resection can be performed by open surgery (laparotomy), through a large incision on the abdominal wall or through 3 to 4 smaller incisions (laparoscopic).
Palliative surgeries are performed to provide relief from symptoms, prevent or help control cancer. Some examples of palliative surgeries include the placement of a stent to open up a blocked duct or bypassing a tumor, so food or other substances can flow freely.
After the surgery, you will be shifted to the recovery room until the sedative effect has worn off. Avoid driving for at least a few days after surgery. The post-operative guidelines differ for different cancer surgeries. For gastrectomy, you may be recommended vitamin B12 injections as absorption of vitamin B12 occurs through the upper part of the stomach. Inform your doctor immediately if you experience fever, chills, vomiting, black or bright red bowel, fainting and shortness of breath after surgery.
You may be instructed not to eat or drink or smoke anything before the procedure. If the procedure is performed in the colon, your surgeon will prescribe a solution for you the day before surgery to cleanse your bowel. Your surgeon will review your daily medications and may instruct you on the medications that you need to avoid.
The biggest benefit of gastrointestinal cancer surgery is the ability to completely remove the cancer. For extensive cancers, surgery is indicated to remove cancer cells to a maximum extent making it easier to be treated with other therapies such as chemo or radiation therapy. Surgery can also be used to treat symptoms of cancer and in many cases prevent/control its growth.
Surgery is the only reliable option for a curative treatment. However, as with any procedure, gastrointestinal cancer surgery may involve certain risks and complications which include bleeding, infection, leakage from the newly connected region after excision, formation of blood clots, damage to nearby organs, frequent heartburn and vitamin deficiencies.
After the procedure, you will be given specific instructions with regard to your diet. You are advised not to lift heavy objects for a few days after the surgery. The care plan varies depending upon the type of surgery and location of cancer. For gastrectomy, your doctor may refer you to a nutritionist to plan your diet and you need to eat small meals more often as the size of the new stomach is smaller. You can gradually resume your daily activities.