Abdominal cancers include cancer of the adrenal cortex, kidney cancer, stomach cancer, cancer of the pancreas, colorectal cancer, carcinoid tumors of the lung or intestine, and multiple endocrine neoplasia syndrome. These abdominal cancers are discussed below.

The adrenal cortex is the outside layer of the adrenal glands. The adrenal glands are a pair of organs near the front side edge of the kidney; their function is to produce hormones such as glucocorticoid and epinephrine. Cancers in this area are classified as carcinomas and adenomas. Adenomas are generally benign, whereas adrenocortical carcinomas frequently secrete hormones and may cause the patient to develop masculine traits, regardless of the patient’s gender. Pediatric patients with adrenocortical carcinoma often have Li-Fraumeni syndrome, an inherited condition that predisposes family members to multiple cancers, including breast cancer, rhabdomyosarcoma, and osteosarcoma (cancer of the bone).

These tumors can involve the kidneys, lungs, and bones. Surgical removal should be attempted but may not always be possible if the tumor has spread widely. Additional treatment may include the use of an artificial hormone that blocks the masculinizing effects of the tumor. The prognosis is generally excellent for patients who have small tumors that have been completely removed by surgery, but prognosis can be poor for patients who have large primary tumors or metastatic disease (disease that has spread to other parts of the body) at diagnosis.

Renal cell carcinoma (cancer of the kidney) occurs rarely in children. The annual incidence rate is approximately 4 cases per 2 million children. Renal cell carcinoma may be associated with von Hippel-Landau disease, a hereditary condition. Renal cell carcinoma has also been associated with tuberous sclerosis, a hereditary disease characterized by benign (noncancerous) fatty cysts in the kidney. Renal cell carcinoma usually presents as an abdominal mass, and there may be discomfort, pain, or blood in the urine. The tumor can spread to the lungs, bones, liver, and lymph nodes and often has spread before the diagnosis is made. The primary treatment includes total surgical removal of the kidney and associated lymph nodes. Treatment of metastatic disease (cancer in other parts of the body) is presently unsatisfactory but usually includes the use of immune system modulators such as interferon-alfa and interleukin-2. Rare spontaneous disappearance of lung metastasis may occur with removal of the primary tumor.

The frequency of, and death rate from, stomach cancer has declined worldwide over the past 50 years with the introduction of food preservation practices such as refrigeration. Symptoms of stomach cancer include vague upper abdominal pain, which can be associated with poor appetite, and weight loss. Many individuals become anemic but otherwise show no symptoms before the development of metastatic spread. Other symptoms may include nausea, vomiting, change in bowel habits, poor appetite and weakness, and Helicobacter pylori infection.

Treatment should include surgery. For individuals who cannot have a complete surgical removal of tissue, radiation therapy may be used along with chemotherapy. Prognosis depends on the extent of the disease at the time of diagnosis and the success of treatment that is appropriate for the clinical situation. Because of the rarity of stomach cancer in the pediatric age group, little information exists regarding treatment outcomes of children.

Tumors of the pancreas (a gland in the abdomen that makes pancreatic juices and produces hormones) are rare in children and adolescents. Tumors included within the general category can arise at any site in the pancreas. Most pancreatic tumors do not secrete hormones, although some tumors secrete insulin, which can lead to symptoms of weakness, fatigue, hypoglycemia, and coma. If a tumor interferes with the normal function of the islet cells (cells in the pancreas that produce hormones), patients may have watery diarrhea or abnormalities of salt balance. At times, there is obstruction of the head of the pancreas, which is associated with jaundice and gastrointestinal bleeding.

Treatment includes various surgical procedures to remove the pancreas and duodenum or part of the pancreas. For pediatric patients, the effectiveness of radiation therapy is not known. Chemotherapy may be useful for treatment of localized or metastatic pancreatic carcinoma, although few cases have been successfully treated. Response rates and survival rates generally are not good.

Cancer of the large bowel is rare in the pediatric age group: one person per one million younger than 20 years in the United States annually. In children, more than half of colon tumors begin on the right side, compared with adults, who have more colon tumors on the left side. Colon cancer in children is often linked to a family colorectal cancer syndrome, or inherited pattern. There is an increasing risk of colorectal cancer in members of families with a family history of intestinal polyps, which can lead to the development of multiple adenomatous polyps (benign tumors). Juvenile polyps are not associated with an increased incidence or risk of cancer.

Colorectal cancer usually presents with symptoms related to the site of the tumor. Changes in bowel habits are associated with tumors of the rectum or lower colon. Tumors of the right colon may cause more subtle symptoms but are often associated with an abdominal mass, weight loss, decreased appetite, and blood in the stool. Any tumor that causes complete obstruction of the large bowel can cause bowel perforation and spread of the tumor cells within the abdominal cavity.

Colorectal carcinoma is rarely diagnosed in a pediatric patient; however, vague gastrointestinal symptoms should alert the physician to investigate this possibility. Most patients present with evidence of metastatic disease (cancer that has spread to other body parts), either as gross tumor or as microscopic deposits in lymph nodes, on the surface of the bowel, or other organs within the abdomen. Complete surgical removal should be the primary aim of the surgeon, but in most instances, this is impossible; removal of large portions of tumor provides little benefit for the individuals with extensive metastatic disease. Most patients with microscopic metastatic disease generally develop gross metastatic disease, and few individuals with metastatic disease at diagnosis become long-term survivors.

Current therapy includes the use of radiation therapy for rectal and lower colon tumors, in conjunction with chemotherapy.

Carcinoid tumors can involve the lining of the lung or the large or small bowel and may not be cancer. Most lung lesions are not cancerous. Treatment of metastatic carcinoid tumors of the large bowel or stomach becomes more complicated and requires treatment similar to that given for colorectal cancer.