The lymphatic system is composed of vessels, nodes, and organs. Lymph vessels are delicate tubes that branch, like blood vessels, into all parts of the body. They carry lymph—a thin, colorless fluid that contains white blood cells called lymphocytes. Throughout the network of vessels are groups of small, densely packed areas of tissue called lymph nodes. Clusters of lymph nodes are found in the neck, underarms, and abdomen. White blood cells are stored in lymph nodes, and from there they are sent out to attack substances or organisms they identify as foreign to the body.

To maintain blood volume, the fluid that routinely leaks from capillaries is collected by the lymphatic system, cleaned, and returned to the circulatory system. Two ducts under the collarbone connect the lymphatic system with large veins in the circulatory system (See Figure 16-1 ). Muscular contractions move lymph through the vessels, and one-way valves direct the flow.

Organ damage

Some children and teens with cancer have lymph nodes removed for biopsy. In some cases, this can result in permanent late effects, such as:

• Hydrocele.  Occurs when fluid collects in the scrotum (most often in males who had abdominal surgery).

• Lymphedema.  Occurs when lymph backs up into an extremity, causing swelling, pain, and loss of function (very rare with modern therapy).

• Impotence.  Occurs in males when lymph node removal or radiation interferes with the nerves that control erections (very rare with modern therapy).

• Ejaculation problems.  Occurs in males who had a radical pelvic lymph node dissection (very rare with modern therapy).

Lymphedema in survivors is generally caused by obstruction due to infection or scar tissue. The most common locations are in the pelvis and legs, or under the arms. Extensive information about lymphedema is available online at the National Cancer Institute’s website at www.cancer.gov/cancertopics/pdq/supportivecare/lymphedema/Patient and the National Lymphedema Network’s site at www.lymphnet.org .

Impotence, hydrocele, and problems with ejaculation are covered in Chapter 14 .

Signs and symptoms

Signs and symptoms of lymphedema are as follows:

• Limb feels full or heavy

• Skin feels tight

• Affected area feels painful and hot

• Limb has decreased flexibility

• Limb has swelling

• Indentations remain in skin when it is pressed (early in the process)

If untreated, the area can become very swollen and the tissues may harden.

Screening and detection

If you have lymphedema, your healthcare provider should take a history and do a careful evaluation of the involved areas. The history should include information about surgeries, radiation, infection, and when the lymphedema started. The circumference of the limb should be measured and circulation checked. Bring a list of your medications to show your healthcare provider, as other medical conditions such as diabetes, kidney problems, high blood pressure, congestive heart failure, or liver disease may contribute to the problem.

Medical management

Medical management of lymphedema includes treatments such as the following:

• Keeping the affected limb raised

• Wearing custom-fitted clothes that apply a uniform pressure

• Using manual lymphatic drainage

Healthcare providers should educate you about additional ways to prevent or control lymphedema, such as the following:

• Proper skin care

• Diet

• Exercise

• Ways to avoid injury or infection (for example, no blood drawing from the affected limb)