Stomach Cancer

Introduction

The stomach is a muscular sac located in the upper middle of the abdomen, just below the ribs. Other organs next to the stomach include the colon, liver, spleen, small intestine, and pancreas. It receives the food from the food pipe (esophagus), holds the food and then helps to break down and digest it by secreting gastric juice, acid and pepsin (digestive enzyme), and intrinsic factor (needed to absorb vitamin B12). The food and gastric juice are mixed and then emptied into the first part of the small intestine called the duodenum. Fig 1.

The stomach has 5 parts Fig 2

•            Cardia: Part closest to the esophagus

•            Fundus: Upper part of the stomach next to the cardia

•            Body (corpus): Main part of the stomach, between the upper and lower parts

•            Antrum: Lower portion (near the intestine), where the food mixes with gastric juice

•            Pylorus: Last part of the stomach, which acts as a valve to control emptying of the stomach

The first 3 parts of the stomach (cardia, fundus, and body) are sometimes called the proximal stomach.  The lower 2 parts (antrum and pylorus) are called the distal stomach. The stomach has 2 curves, which form its inner and outer borders. They are called the lesser curvature and greater curvature, respectively.

Stomach cancer/ Gastric Cancer Fig 3

Stomach cancer is an abnormal growth of cells that begins in the stomach. Stomach cancer, also known as gastric cancer, can affect any part of the stomach.  Stomach cancers tend to develop slowly over many years. Before a true cancer develops, pre-cancerous changes often occur in the inner lining (mucosa) of the stomach. These early changes rarely cause symptoms and therefore often go undetected.

Types

Adenocarcinoma: Most (about 90% to 95%) cancers of the stomach are adenocarcinomas. A stomach cancer or gastric cancer almost always is an adenocarcinoma. These cancers develop from the cells that form the innermost lining of the stomach (the mucosa).

Lymphoma: These are cancers of the immune system tissue that are sometimes found in the wall of the stomach. The treatment and outlook depend on the type of lymphoma.

Gastrointestinal stromal tumor (GIST): These tumors start in cells in the wall of the stomach called interstitial cells of Cajal. Some of these tumors are non-cancerous (benign); others are cancerous. Although GISTs can be found anywhere in the digestive tract, most are found in the stomach.

Carcinoid tumor: These tumors start in hormone-making cells of the stomach. Most of these tumors do not spread to other organs.

Other cancers: Other types of cancer, such as squamous cell carcinoma, small cell carcinoma, and leiomyosarcoma, can also start in the stomach, but these cancers are rare.

Symptoms

Often there are no early symptoms of stomach cancer. Screening methods are available that can detect stomach cancer before symptoms appear. When detected early, these cases can be cured with much simpler surgery. As the cancer advances, stomach cancer symptoms may become more persistent and severe.

In the early stages of stomach cancer, the following symptoms may occur:

  • Indigestion, heartburn, and stomach discomfort
  • Bloated feeling in upper abdomen after eating
  • Mild nausea
  • Loss of appetite

In more advanced stages of stomach cancer, the following signs and symptoms may occur:

  •  Blood in the stool
  • Vomiting, with or without blood in it
  • Weight loss
  • Stomach pain
  • Jaundice (yellowing of eyes and skin)
  • Ascites (build-up of fluid in the abdomen
  • Trouble swallowing
Risks

Factors that may increase risk of stomach cancer include:

  • Older age
  • Gastroesophageal reflux disease
  • Obesity
  • A diet high in salty and smoked foods
  • A diet low in fruits and vegetables
  • Family history of stomach cancer
  • Infection with Helicobacter pylori
  • Long-term stomach inflammation (gastritis)
  • Smoking
  • Stomach polyps

Diagnosis Tests

In addition to a physical examination, the following tests may be used to diagnose stomach cancer. Not all tests listed below will be used for every person.

  • Upper GI endoscopy/ Gastroscopy/ OGDscopy Figure7 Gastroscopy allows the doctor to look inside the esophagus, stomach, and duodenum. A gastroscope is a thin long flexible tube with a camera at its tip, which helps the doctor to see for any growth, tumour or polyp.
  • Endoscopic ultrasound: This test uses a special scope with small ultrasound probe on the end. An ultrasound uses sound waves to depict a picture of the internal organs. An ultrasound image of the stomach wall helps to determine how far the cancer has spread into the stomach and nearby lymph nodes, tissue, and organs.
  • Biopsy: Biopsy is the removal of a small amount of tissue for examination under a microscope. Biopsy can make a definite diagnosis of stomach cancer. A biopsy may be performed during a gastroscopy, or it may be done on any tissue that is removed during surgery.
  • Blood tests: Stomach cancer often bleeds into the digestive tract, so people with the disease may become anemic. Complete blood count (CBC) can indicate that bleeding may be occurring.
  • Computed tomography (CT or CAT) scan: A CT scan takes pictures of the inside of the body. It can be used to measure the tumor’s size. Special dye called a contrast medium is given before the scan to provide better images. This dye can be injected into a patient’s vein or given as a pill or liquid to swallow. In a person with stomach cancer, a CT scan can check for the spread of cancer to the lungs, liver, and other organs.
  • Ultrasound: An ultrasound uses sound waves to create a picture of the internal organs to find out if cancer has spread.
  • Chest x-ray: X-ray of the chest can help doctors find out if the cancer has spread to the lungs.
  • Positron emission tomography (PET) or PET-CT scan.  PET scan is a way to create pictures of organs and tissues inside the body. A small amount of a radioactive substance is injected into the patient’s body. Because cancer tends to use energy actively, it absorbs more of the radioactive substance. A scanner then detects this substance to produce images of the cancer.
Stages

There are different stage descriptions for different types of cancer. This section covers staging of adenocarcinoma, the most common type of stomach cancer. Staging is different for gastric lymphoma, GIST tumours, and neuroendocrine tumors.

Stage 0 & IA

Stage 0 & IA cancers are limited to the inner layer of the stomach (mucosa) and have not grown into deeper layers, they can be treated by surgery alone. No chemotherapy or radiation therapy is needed. However, this stage can only be confirmed after surgery in most cases. The part of stomach to be removed depends on the location of the tumour. It could be either proximal gastrectomy (removal of upper half of the stomach), subtotal gastrectomy (removal of lower part of the stomach) or total gastrectomy (removal of the entire stomach). Nearby lymph nodes are removed as well.

These surgeries can be performed by open surgery or laparoscopically or robotically. Robotic and laparoscopic surgery for stomach cancer reduces the trauma to the patient and leads to quick recovery. Alternative treatment for this stage would be endoscopic mucosal resection of the tumor, but this can only be offered for select cases.

Stage I B

Stage IB is when cancer has spread beyond the inner lining into the muscle layer or 1 or 2 lymph nodes near stomach are involved (can only be confirmed after surgery). The main treatment for this stage of stomach cancer is surgery (radical total or subtotal gastrectomy). Radical indicates that the lymph nodes around stomach are removed (D2 dissection). These surgeries also can be performed by open conventional surgery or robotically or laparoscopically. Chemotherapy (chemo) or chemoradiation (chemo plus radiation therapy) may be given before surgery to try to shrink the cancer and make it easier to remove.

Stage II

Stage II is when cancer has involved the entire thickness of the wall of stomach growing into the outer lining (serosa) or involved more than 2 lymph nodes (can be confirmed only after surgery). The main treatment for stage II stomach cancer is surgery (radical total or subtotal gastrectomy). Like stage I cancers, robotic and laparoscopic surgery reduces the trauma to the patient and yield in quick recovery. Chemotherapy or chemoradiation before or after surgery must be given in many of these cases.

Stage III

Stage III is a locally advanced disease wherein the cancer has spread outside the wall of stomach or there are large number of lymph nodes involvement around stomach. Surgery is the main treatment for patients with this stage disease robotic and laparoscopic surgery reduces the trauma to the patient and yield in quick recovery. Some patients may be cured by surgery (along with other treatments), while for others the surgery may be able to help control the cancer or help relieve symptoms. Many patients are treated with chemotherapy or chemoradiation before or after surgery.

Stage IV

Stage IV stomach cancer describes a cancer of any size that has spread to distant parts of the body (lungs, liver, or brain) in addition to the area around the stomach. Because stage IV stomach cancer has spread to other organs, a cure is usually not possible. Treatment helps to keep the cancer under control and help relieve symptoms of stomach blockage. This might include surgery, such as a gastric bypass (gastro-jejunostomy) or even a subtotal gastrectomy in some cases, to keep the stomach and/or intestines from obstructed blocked or to control bleeding. Robotic or laparoscopic subtotal gastrectomy or gastro-jejunostomy will help these patients in quick recovery and go for the next line of treatment.

Treatments

SURGERY: The only treatment that can cure stomach cancer is surgery. All other forms of treatment like chemotherapy and radiotherapy can only reduce risk of recurrence of cancer after surgery but cannot cure the cancer. Several different surgical procedures are available to treat tumours of the stomach. The choice of surgery depends upon the location, size, and type of the tumor. Gastric adenocarcinoma requires extensive surgery with removal of tumour with surrounding normal stomach and surrounding lymph nodes, whereas GIST tumours require removal of only the tumour. (Figure9)

Distal Gastrectomy/ Subtotal gastrectomy (Fig 10) (Fig 11)

This operation is often recommended if the cancer is only in the lower part of the stomach.  The lower half of the stomach is removed, along with the omentum (an apron-like layer of fatty tissue that covers the stomach and intestines) and nearby lymph nodes, and possibly the spleen and parts of other nearby organs. The remaining section of stomach is then reattached to the intestines. Eating is much easier after surgery if only part of the stomach is removed instead of the entire stomach.

Proximal Gastrectomy

This operation is often recommended if the cancer is only in the upper part of the stomach.  The lower half of the stomach is removed, along with the omentum (an apron-like layer of fatty tissue that covers the stomach and intestines) and nearby lymph nodes, and possibly the spleen and parts of other nearby organs. The remaining section of stomach is then reattached to the intestines.

Total gastrectomy

This operation is done if the cancer has spread throughout the stomach. It is also often advised if the cancer is in the upper part of the stomach, near the oesophagus.

The entire stomach, nearby lymph nodes, and omentum are removed.  Depending on the tumour, the spleen, and parts of the oesophagus, intestines, pancreas, or other nearby organs may need removal too. The end of the oesophagus is then attached to part of the small intestine.

Placement of a feeding tube

Some patients have trouble taking in enough nutrition after surgery for stomach cancer. To help with this, a tube can be placed into the intestine at the time of gastrectomy. The end of this tube, called a jejunostomy tube or J tube, remains outside of the skin on the abdomen. Through this, liquid nutrition can be put directly into the intestine to help prevent and treat malnutrition.

Lymph node removal

In either a subtotal or total gastrectomy, the nearby lymph nodes are removed. This is a particularly important part of the operation. The success of the surgery is related to how many lymph nodes the surgeon removes.

It is recommended that at least 15 lymph nodes are removed (called a D2 lymphadenectomy) when a gastrectomy is done.

Palliative surgery for unresectable cancer

For people with unresectable stomach cancer, surgery can often still be used to help control the cancer or to help prevent or relieve symptoms or complications.

Subtotal gastrectomy: For some people who are healthy enough for surgery, removing the part of the stomach with the tumour can help treat problems such as bleeding, pain, or blockage in the stomach, even if it does not cure the cancer. Because the goal of this surgery is not to cure the cancer, nearby lymph nodes and parts of other organs usually do not need to be removed.

Gastric bypass (gastrojejunostomy): Tumours in the lower part of the stomach may eventually grow large enough to block food from leaving the stomach. For people healthy enough for surgery, one option to help prevent or treat this is to bypass the lower part of the stomach. This is done by attaching part of the small intestine (the jejunum) to the upper part of the stomach, which allows food to leave the stomach through the new connection.

Stent placement: Another option to keep a tumour from blocking the opening at the beginning or end of the stomach is to use an endoscope to place a stent (a hollow metal tube) in the opening. This helps keep it open and allows food to pass through it. For tumours in the upper (proximal) stomach, the stent is placed where the oesophagus and stomach meet. For tumours in the lower (distal) part of the stomach, the stent is placed at the junction of the stomach and the small intestine.

Feeding tube placement: Some people with stomach cancer are not able to eat or drink enough to get adequate nutrition. A minor operation can be done to place a feeding tube through the skin of the abdomen and into the distal part of the stomach (known as a gastrostomy tube or G tube) or into the small intestine (jejunostomy tube orJ tube). Liquid nutrition can then be put directly into the tube.

Surgery Techniques

Open surgery: It involves large cuts or incisions on the patient’s body to make a big opening through which the surgery is done. It is highly painful; there is chance of increased blood loss, infection, and prolonged recovery. (Fig 12)

Minimal invasive surgery: In these surgeries, the entire procedure is performed using small keyhole incisions, which leads to less pain, less blood loss, faster recovery of the patient. These can be done with laparoscopic or robotic techniques.

Using minimal invasive technique, stomach cancer surgery can be performed with improved comfort. Gastrectomy when performed by laparoscopy or robotic surgery avoids most of the complications which are mainly related to wound. Patients will have faster recovery, with less blood loss, less chances of infection and less chances of hernia later. 

Robotic surgery for stomach cancer: The surgeon operates several precision-guided robotic arms that hold and manipulate miniaturized instruments that are inserted through keyhole-sized incisions. A small video camera provides surgeons with magnified 3D images of the operating site. The robotic arms, which can rotate 360 degrees, enable surgical instruments to be moved with greater precision, flexibility, and range of motion than in standard minimally invasive laparoscopy.

Most procedures take two to three hours under general anesthesia. Patients typically experience only minimal blood loss, and blood transfusions are rarely needed. Depending on the surgery, patients often only spend few nights in the hospital and are usually discharged as soon as their laboratory tests are acceptable, their pain is controlled, and they can retain liquids.

Chemotherapy: Chemotherapy uses drugs to destroy cancer cells. For stomach cancer, chemotherapy might be recommended after surgery to kill any cancer cells that might remain. Chemotherapy combined with radiation therapy might also be used before an operation to shrink a large cancer so that it is easier to remove with surgery. Chemotherapy can also be used to relieve symptoms of stomach cancer that cannot be removed with surgery or that has spread to other areas of the body.

Radiation therapy: Radiation therapy uses powerful energy sources, such as X-rays and protons, to kill cancer cells. In people with stomach cancer, radiation therapy is often combined with chemotherapy that makes the cancer cells more likely to be damaged by the radiation. It can be used after surgery to kill any cancer cells that might remain. Or it can be used before surgery to shrink a cancer and make it easier to remove.

Combined chemotherapy and radiation therapy: Combining chemotherapy and radiation therapy (chemoradiotherapy) makes cancer cells more vulnerable to radiation. The combination is often used for larger stomach cancers and those that have a higher risk of returning after surgery.

Chemoradiotherapy may be recommended:

  • Before surgery: Chemoradiotherapy may help shrink the cancer enough to make a less invasive surgery possible.
  • After surgery: If surgery was the first treatment, doctor may recommend chemoradiotherapy afterward if there is an increased risk that the cancer may return.
  • As the primary treatment: Doctor may recommend chemoradiotherapy to control the growth of cancer if cancer is advanced or if surgery is not an option.

Surgery for stomach cancer is difficult and can have complications. These can include bleeding from the surgery, blood clots, and damage to nearby organs during the operation. Rarely, the new connections made between the ends of the stomach or esophagus and small intestine may leak.

Surgery for stomach cancer takes a skilled surgeon who is experienced in stomach cancer surgery to remove all the lymph nodes successfully. Studies have shown that the results are better when the surgeon has extensive experience in treating patients with stomach cancer. The outcome of this surgery is more likely to be successful if performed by a qualified and experienced GI cancer surgeon

Dr. Aditya Kulkarni is the best stomach cancer surgeon, advanced laparoscopic cancer surgeon and robotic surgeon in Pune, Maharashtra, who is qualified and experienced in gastrointestinal cancer surgery.

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