Kaposi's Sarcoma

Initially, this cancer of the lymphatic cell wall was described as a rare blood vessel sarcoma, occurring mostly in elderly Italian and Jewish men. In recent years, the incidence of Kaposi's sarcoma has risen dramatically along with the incidence of acquired immunodeficiency syndrome (AIDS). Currently, it's the most common AIDS-related cancer.

Kaposi's sarcoma causes structural and functional damage. When associated with AIDS, it progresses aggressively, involving the lymph nodes, the viscera and, possibly, GI structures.

Causes

The epidemic KS, occurring as a disease that accompanies AIDS, is thought to have a cause - the virus named HIV (Human Immunodeficiency Virus). If given a blood test for HIV, nearly all patients with epidemic KS will show evidence of being infected.

Various ideas have been advanced to explain how this virus causes KS. One theory is that it causes a normal cell to become malignant either directly or by initiating a chain of events. Various agents that may be involved in such a change have been identified.

Yet another idea has to do with the body's T cells, some of which hunt for malignant cells that have developed spontaneously and kill them off before they can become cancers. The T cell is known to be infected with the virus and cannot kill the malignant cells.

Signs and symptoms

The initial sign of Kaposi's sarcoma is one or more obvious lesions in various shapes, sizes, and colors (ranging from red brown to dark purple) that appear most commonly on the skin, buccal mucosa, hard and soft palates, lips, gums, tongue, tonsils, conjunctivae, and sclerae.

In advanced disease, the lesions may join, becoming one large plaque. Unmasses.

Other signs and symptoms include:

• a health history of AIDS
• pain (if the sarcoma advances beyond the early stages or if a lesion breaks down or impinges on nerves or organs)
• edema from lymphatic obstruction
• dyspnea (in cases of pulmonary involvement), wheezing, hypoventilation, and respiratory distress from bronchial blockage.

The most common extracutaneous s'ites are the lungs and GI tract (esophagus, oropharynx, and epiglottis).

Signs and symptoms of disease progression and metastasis include severe pulmonary involvement and GI involvement leading to digestive problems.

Diagnosis

Many physicians will diagnose KS based on the appearance of the skin tumors and the patient's medical history. Unexplained cough or chest pain, as well as unexplained stomach or intestinal pain or bleeding, could suggest that the disease has moved beyond the skin. The most certain diagnosis can be achieved by taking a biopsy sample of a suspected KS lesion and examining it under high-power magnification. For suspected involvement of internal organs, physicians will use a bronchoscope to examine the lungs or an endoscope to view the stomach and intestinal tract.

Treatment

In Kaposi's sarcoma, treatment isn't indicated for all patients. Indications include cosmetically offensive, painful, or obstructive lesions of rapidly progressing disease.

Radiation therapy, chemotherapy, and biotherapy with biological response modifiers are treatment options. Radiation therapy alleviates symptoms, including pain from obstructing lesions in the oral cavity or extremities and edema caused by lymphatic blockage. It may also be used for cosmetic improvement.

Chemotherapy includes combinations of doxorubicin, vinblastine, vincristine, and etoposide (VP-16).

Biotherapy with interferon alfa-2b may be administered for AIDS-related Kaposi's sarcoma. The treatment reduces the number of skin lesions but is ineffective in advanced disease.

Prevention

Safe sexual practices can prevent infection with HIV, which in turn prevents the development of AIDS and its complications, including Kaposi's sarcoma.

Large clinical trials underway in 2003 were showing some promise for preventing infection with HHV-8 through prophylaxis (preventive medication) with antiherpes drugs