Effects of Treatment on Nutritional Status

Various treatments may be used for cancer with the goal of curing it or palliating symptoms (Table 2). All may potentially affect nutritional status.

The treatment chosen depends on the position of the tumor, its extent, and its sensitivity to radiotherapy or chemotherapy. Often, different treatments will be used in succession (e.g., surgery followed by chemotherapy, or radiotherapy followed by surgery).

Table 2 Treatment for cancer

Treatment

Examples

Table 3 Side effects of chemotherapy that may affect nutritional status

Surgery Removal of tumor

Removal of organ (e.g., gastrectomy, nephrectomy, colectomy) Palliation of symptoms (e.g., intestinal bypass, colostomy formation) Chemotherapy Single agent

Combination of agents Drugs given as single dose or continuous infusion (e.g., methotrexate, epirubicin, mytoycin, fluorouracil) Radiotherapy External bean

Single fractions daily Hyperfractionated

Intensity modulated radiation therapy Brachytherapy—interstitial (e.g., iridium wires) Radioisotopes (e.g., iodine 131) Biological Interferon therapies Interleukin Endocrine Tamoxifen therapies Aminoglutethimide Goserelin

Medroxyprogesterone acetate Megestrol acetate

Alternatively, treatments may be used concurrently (e.g., chemoradiation). The effect of treatment on nutritional status depends on the site of the tumor and the treatment given.

Surgery is used to remove all or part of the tumor or to bypass the tumor, thereby allowing organs to continue to function. There are often periods of starvation before and after surgery that may contribute to malnutrition in the cancer patient.

The trauma of surgery causes an increase in the production of catecholamines such as adrenaline, which results in the obligatory loss of nitrogen from the body. Repeated or extensive surgery contributes to an increase in metabolic rate and therefore contributes to nutritional depletion.

Chemotherapy is based on the use of drugs that interrupt the cell cycle and prevent cell multiplication. The drugs act on rapidly proliferating cells and also damage healthy cells, particularly those in the gastrointestinal tract and hair follicles. They may also cause nausea and vomiting, altered taste, nerve damage, and infertility. Drugs may be given orally, intravenously (bolus or continuous infusion), or intrathecally. High-dose chemotherapy may be used with a stem cell rescue. Table 3 lists commonly used chemotherapeutic agents and their side effects that affect nutritional status.

Radiotherapy is the use of ionizing radiation to destroy malignant cells. External beam radiation is most commonly used. It may be used in combination

Table 3 Side effects of chemotherapy that may affect nutritional status

Agent

Side effects

Methotrexate

Severe mucositis

Nausea (dose dependent)

Vomiting

Vincristine

Paralytic ileus

Fluorouracil

Diarrhea

Occasional nausea

Cisplatin

Anorexia

Severe prolonged nausea

Nausea and vomiting

Taste changes (particularly a metallic taste)

Diarrhea (high doses)

Doxorubicin

Nausea

Some vomiting

Mucositis throughout gastrointestinal tract

Docetaxol

Diarrhea

with chemotherapy to enhance the effects of both treatments.

Biological therapies are based on the use of cyto-kines derived from cells in the immune system. Cytokines are administered to stimulate the body's immune response to reduce or prevent tumour growth and often cause anorexia.

Endocrine therapies are primarily used to control the growth of hormone-dependent cancers, such as cancer of the breast or prostate. Drugs may be used to block production of hormones or to block hormone receptors.

Head and Neck Cancer

Surgical resection is often used for cancers of the oropharynx. Removal of the tumor and reconstruction may lead to periods when the patient is not allowed to eat or drink in order to allow healing to take place. Resection of the mandible, tongue, maxilla, or pharynx may lead to difficulties with chewing or swallowing. There may be an increased risk of aspiration because of a poor ability to control food or fluids in the mouth or because of an alteration in the anatomy or cranial nerves required for swallowing.

Radiotherapy to the head and neck can have a significant impact on nutritional status with both early side effects, during or immediately after treatment, and late side effects, which may occur years after treatment (Table 4). Reduced food intake and weight loss due to soreness and dysphagia are particularly common and occur in up to approximately 90% of patients. A dry mouth (xerostomia) occurs when the salivary glands are irradiated and leave the teeth increasingly prone to tooth decay.

Table 4 Side effects of radiotherapy to the head and neck

Early

Late

Mucositis (inflammation of

Mucosal ulceration

the mucosa)

Xerostomia

Stomatitis (inflammation of

Increased viscosity of saliva

the mouth)

Xerostomia (dry mouth)

Dysphagia

Increased viscosity of saliva

Altered taste

Dysphagia (difficulty

Mouth blindness

swallowing)

Altered taste

Dental caries

Mouth blindness

Trismus (inability to open

mouth)

Nausea

Fibrosis (formation of

Anorexia

excessive fibrous tissue)

Loss of smell

Stenosis (narrowing)

Fistula

Poor wound healing

Osteoradionecrosis

(degeneration of bone)

Chemotherapy may be used in combination with surgery and occasionally given concurrently with radiotherapy. Reduced food intake results from nausea, vomiting, learned food aversions, anorexia, and mucosititis. Artificial nutritional support may be required during treatment if oral intake is significantly reduced.

Gastrointestinal Cancer

Surgery, chemotherapy, and radiotherapy treatments may be used for cancers of the gastrointestinal tract, depending on the site and type of disease. The impact of both disease and treatment on nutritional status is often great, particularly in upper gastrointestinal cancers.

Surgical resection of the upper gastrointestinal tract often affects the capacity to ingest food and fluids. Surgery that changes the length or motility of the small intestine affects the ability to digest and absorb food and fluids (Table 5). Tumors of the small intestine are rare, but small intestinal resection may be necessary because of strictures caused by previous abdominal or pelvic radiotherapy or because of adhesions from previous surgery.

Radiotherapy is often used to treat tumors of the gastrointestinal tract. It can severely affect the ingestion, digestion, and absorption of food and fluids (Table 6). Chronic malabsorption of bile salts contributes to fat malabsorption. Bile salts entering the colon inhibit water absorption and stimulate colonic peristalsis, causing fluid and electrolyte deficiencies.

Chemotherapy for gastrointestinal tumors is often associated with side effects such as anorexia, nausea, vomiting, and mucositis (inflammation of the

Table 5 Nutritional consequences of surgery to the gastrointestinal tract

Area of gastrointestinal Impact on nutritional status tract resected

Table 5 Nutritional consequences of surgery to the gastrointestinal tract

Area of gastrointestinal Impact on nutritional status tract resected

Oesophagus

Intestinal hurry (due to vagotomy and

pyloroplasty)

Reduced gastric capacity (due to

stomach pull up)

Stricture at anastomosis (surgical

junction)

Dumping syndrome

Stomach

Reduced capacity for food and fluids

Early satiety

Dumping syndrome

Intestinal hurry (due to vagotomy and

pyloroplasty)

Fat malabsorption

Anemia (lack of intrinsic factor)

Small intestine

General malabsorption

Diarrhea

Terminal ileum

Malabsorption of vitamin B12

Fat malabsorption

Decreased absorption of bile salts,

fat-soluble vitamins, and minerals

Short bowel syndrome

gastrointestinal mucosa). Learned food aversions, which arise through the association of particular foods with vomiting induced by chemotherapy, may also have an impact on nutritional intake.

Leukemias and Lymphomas

Systemic diseases such as leukemias and lymphomas are usually treated with chemotherapy. Chemotherapy is generally given intermittently to allow the bone marrow to recover. Patients experience anorexia, severe mucositis, nausea, vomiting, taste changes, food aversions, tiredness, and lethargy. Some drugs, such as doxorubicin, may reduce gut motility and increase the risk of gastrointestinal obstruction.

Table 6 Effects of radiotherapy on the gastrointestinal tract

Area irradiated Side effects

Oesophagus Dysphagia

Mucositis Fibrosis

Stomach Anorexia

Nausea Vomiting

Abdomen and pelvis Anorexia

Nausea Vomiting Diarrhea Malabsorption Early enteritis Chronic enteritis

Radiotherapy may be used to treat isolated lymph nodes, as in the case of lymphoma, or it may be used to abolate the immune system prior to a bone marrow transplant or peripheral stem cell rescue. Profound neutropenia may results in bouts of sepsis and increased nutritional requirements due to pyrexia.

Bone Marrow Transplant

Bone marrow transplantation (BMT) carries a high risk of patients developing malnutrition due to the severe side effects of high-dose chemotherapy and whole-body irradiation. BMT may be used to treat acute myeloid leukemia, acute lymphoblastic leukemia, chronic myeloid leukemia, and lymphoma. Side effects that alter nutritional status are more likely to occur in allografts, in which the bone marrow from a matched or mismatched donor is used rather than the patient's own bone marrow. Graft versus host disease may occur in allogenic BMT. It is characterized by inflammation of the skin, which may cause increased nutritional requirements. Other symptoms include gastrointestinal involvement with severe diarrhoea; loss of blood, mucus, and tissue via the gastrointestinal tract; and increased fluid losses. There may also be liver involvement and altered liver function (Table 7).

Gynecological Cancer

Treatment for cancer of the ovary, uterus, or cervix can have a major impact on nutritional status (Table 8). Malignant disease, surgery, or radiotherapy in the pelvis can lead to adhesions, strictures of the bowel, malabsorption, and bowel obstruction. Irreversible damage may necessitate a gastrointestinal resection or the formation of an ileostomy or colostomy. Malignant ascites can impinge on the gastrointestinal tract due to pressure exerted by fluid within the abdomen, causing anorexia and early satiety. Chemotherapeutic drugs (e.g., cisplatin) used to treat gynecological cancers cause severe

Table 7 Side effects of bone marrow transplantation affecting nutritional status

Early

Late

Anorexia Weight loss Vomiting Stomatitis Xerostomia Diarrhea Malabsorption Taste changes

Acute graft versus host disease

Anorexia

Weight loss

Xerostomia

Taste changes

Chronic graft versus host disease Somnolence

Table 8 Nutritional problems in gynecological cancer

Anorexia Early satiety Nausea Vomiting Taste changes

Radiation enteritis, early or late Short bowel syndrome Subacute bowel obstruction Complete bowel obstruction nausea and vomiting and therefore greatly reduce food intake.

Brain Tumors

Brain tumors are generally treated with surgery followed by radiotherapy or chemotherapy. A small percentage of patients may develop dysphagia as a result of the tumor, the treatment, or both, particularly in tumors of the brain stem. Patients may also experience taste changes, which can be severe and permanent, and somnolence following brain radiotherapy. High-dose steroids, such as prednisolone or dexamethasone, may cause increased appetite, steroid-induced diabetes mellitus, and weight gain.

Breast Cancer

Breast cancer patients are often treated with surgery, radiotherapy, and chemotherapy. Because surgery and radiotherapy are performed away from the gastrointestinal tract, these treatment modalities rarely have a major impact on nutritional status. Chemotherapy with drugs such as epirubicin may cause nausea, vomiting, and stomatitis (inflammation of the mouth), and docetaxol may cause diarrhea. In advanced disease, mediastinal nodes may cause dysphagia, and secondary liver disease may cause anorexia and nausea. Chemotherapy may cause general anorexia, lethargy, and nausea in some patients, although there is evidence that many breast cancer patients may gain weight during chemotherapy or when taking hormone treatments.

Cancer in Children

Malnutrition is common in children undergoing treatment for cancer because treatment is often aggressive and multimodal. Malnurition may occur in approximately one-third of all pediatric patients but is more common in certain diagnostic groups. High-risk diagnoses include Ewing's sarcoma, Wilms' tumor, head and neck tumors, advanced lymphomas, and neuro-blastoma. Malnutrition and anticancer treatment in children may affect their future growth. The possible causes of malnutrition are listed in Table 9.

Table 9 Causes of malnutrition in children with cancer

Increased metabolic rate

Mechanical gastrointestinal problems (e.g., tumor pressing on stomach or gastrointestinal tract) Malabsorption Nausea Vomiting

Taste abnormalities

Mucositis

Stomatitis

Dysphagia

Diarrhea

Somnolence

Behavioral and environmental factors Poor eating habits Learned food aversions Noncompliance with dietary regimens micro-organisms, many of which are part of the human diet. Some carcinogens have also been introduced into the human diet as a result of traditional cooking and preserving practices. Although carcinogens act through a wide variety of mechanisms, a substantial number have a common mechanism of action in that they react with the genetic material of the body, DNA. These so-called genotoxic carcinogens generally require metabolic activation to express their carcinogenicity. Although substantial efforts are being made to develop short-term, non-animal tests to predict the carcinogenicity of chemicals, animal bioassays remain the only reliable method for establishing the potential of a chemical to be a carcinogen, and form the basis of current approaches for the control of potentially carcinogenic chemicals in the human diet.

See also: Ascorbic Acid: Physiology, Dietary Sources and Requirements; Deficiency States. Cancer: Effects on Nutritional Status; Epidemiology and Associations Between Diet and Cancer. Diabetes Mellitus: Etiology and Epidemiology; Classification and Chemical Pathology. Small Intestine: Disorders; Structure and Function. Stomach: Disorders; Structure and Function.

Losing Weight Natures Way

Losing Weight Natures Way

Feel Healthier And Look Better Without Resorting To Drugs! Would you like to get your hands on a this report that can teach you everything you need to know about losing weight naturally?

Get My Free Ebook


Post a comment