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KS was first described in 1872 by the Hungarian dermatologist, Moritz Kaposi. From that time until the current human immunodeficiency virus (HIV) disease epidemic identified with the Acquired Immunodeficiency Syndrome (AIDS), KS remained a rare tumor. While most of the cases seen in Europe and North America have occurred in elderly men of Italian or Eastern European Jewish ancestry, the neoplasm also occurs in several other distinct populations: young black African adult males, prepubescent children, renal allograft recipients, and other patients receiving immunosuppressive therapy. The disseminated, fulminant form of KS associated with HIV disease is referred to as epidemic KS to distinguish it from the classic, African, and transplant-related varieties of the neoplasm. In addition, KS has been identified in homosexual men apart from the HIV disease epidemic.
Although the histopathology of the different types of the Kaposi tumor is essentially identical in all of these groups, the clinical manifestations and course of the disease differ dramatically. A key piece to the puzzle of KS pathogenesis was the 1994 discovery of a gamma herpes virus, human herpes virus type 8 (HHV-8), also known as Kaposi sarcoma herpes virus. HHV-8 was identified in KS tissue biopsies from virtually all patients with classic, African, transplant-related, and AIDS-associated KS but was absent from noninvolved tissue.[4,5,6,7]
Classic Kaposi Sarcoma
Considered a rare disease, classic KS occurs more often in males, with a ratio of approximately 10 to 15 males to 1 female. In North Americans and Europeans, the usual age at onset is between 50 and 70 years. Classic KS tumors usually present with one or more asymptomatic red, purple, or brown patches, plaques, or nodular skin lesions. The disease is often limited to single or multiple lesions usually localized to one or both lower extremities, especially involving the ankles and soles.
Classic KS most commonly runs a relatively benign, indolent course for 10 to 15 years or more, with slow enlargement of the original tumors and the gradual development of additional lesions. Venous stasis and lymphedema of the involved lower extremity are frequent complications. In long-standing cases, systemic lesions can develop along the gastrointestinal tract, in lymph nodes, and in other organs. The visceral lesions are generally asymptomatic and are most often discovered only at autopsy, though clinically, gastrointestinal bleeding can occur. As many as 33% of the patients with classic KS develop a second primary malignancy, which is most often non-Hodgkin lymphoma.[8,9,10]
African Kaposi Sarcoma
In the 1950s, KS was recognized as a relatively common neoplasm endemic in native populations in equatorial Africa and comprised approximately 9% of all cancers seen in Ugandan males. African KS is seen as either an indolent neoplasm identical to the classic disease seen in Europe and North America or as an aggressive disease with fungating and exophytic tumors that may invade the subcutaneous and surrounding tissue including the underlying bone. In Africa, both the indolent and locally more aggressive forms of KS occur with a male-to-female ratio comparable to that observed with the classic KS tumor seen in North America and Europe. In general, however, patients in Africa are significantly younger than their European counterparts. A lymphadenopathic form of KS is also seen in Africa, primarily in prepubescent children (male:female ratio, 3:1). In these cases, the generalized lymphadenopathy is frequently associated with visceral organ involvement. The prognosis is very poor with a 100% fatality rate within 3 years.[11,12]
Immunosuppressive Treatment-Related Kaposi Sarcoma
In 1969, the first case of KS in association with immunosuppression in a renal transplant patient was described. Since that time, a number of renal and other organ allograft recipients who received prednisone and azathioprine developed KS shortly after the onset of immunosuppressive therapy. Estimates of the incidence of KS in immunosuppressed renal transplant recipients are between 150 and 200 times the expected incidence of the tumor in the general population. The average time to develop KS after transplantation is 16 months. Although the KS tumor in iatrogenically immunosuppressed patients often remains localized to the skin, widespread dissemination with mucocutaneous or visceral organ involvement is common. In some cases, the KS tumors have regressed as a result of reduction or changes in immunosuppressive therapy. Clinical management of renal transplant patients who develop KS is difficult and requires a balance between the risk of death from generalized KS and the risk of graft rejection and complications of renal failure that may occur if the immunosuppressive therapy is discontinued.
Epidemic Kaposi Sarcoma
In 1981, a fulminant and disseminated form of KS in young homosexual or bisexual men was first reported as part of an epidemic now known as AIDS. The etiology of AIDS is a T-cell lymphotropic retrovirus known as HIV. The underlying immunologic deficiency that characterizes HIV disease is an acquired profound disorder of cell-mediated immune functions. This immunologic deficiency and immune dysregulation predisposes the host to a variety of opportunistic infections and unusual neoplasms, especially KS. HIV may play an indirect role in the development of KS.
Approximately 95% of all the cases of epidemic KS in the United States have been diagnosed in homosexual or bisexual men. In the past, approximately 26% of all homosexual males with HIV disease presented with, or eventually developed, KS during the course of their illness. By comparison, fewer than 3% of all heterosexual intravenous drug users with HIV disease developed KS. The proportion of HIV disease patients with KS has steadily decreased since the epidemic was first identified in 1981. About 48% of AIDS patients in 1981 had KS as their presenting AIDS diagnosis. By August 1987, the cumulative proportion of AIDS patients with KS had diminished to fewer than 20%. The introduction of combined antiretroviral therapy (cART) has delayed or prevented the emergence of drug-resistant HIV strains, profoundly decreased viral load, led to increased survival, and lessened the risk of opportunistic infections.[17,18,19] The use of cART has been associated with a sustained and substantial decline in KS incidence in multiple large cohorts.[20,21,22,23,24,25]
The lesions that develop may involve the skin; oral mucosa; lymph nodes; and visceral organs, such as the gastrointestinal tract, lung, liver, and spleen. Most patients with HIV disease who present with the mucocutaneous lesions of KS feel healthy and are usually free of systemic symptoms, as compared with HIV patients who first develop an opportunistic infection. The sites of disease at presentation of epidemic KS are much more varied than the sites seen in other types of this neoplasm. In an early report on the clinical manifestations of the disease, 49 patients were described. Of these patients, 8% had no skin involvement, 27% had localized or fewer than five skin lesions, and 63% had innumerable skin lesions widely distributed over the skin surface area. Of these patients, 61% had generalized lymphadenopathy at the time of the first examination. Four of these patients, who had generalized lymphadenopathy in the absence of skin lesions or detectable visceral organ involvement at the time of presentation, were found to have biopsy-proven KS localized to the lymph nodes. In 45% of the patients studied, KS lesions were found in one or more sites along the gastrointestinal tract. Of these patients, 29% had either unexplained fever or unexplained weight loss when first seen. While most patients present with skin disease, KS involvement of lymph nodes or the gastrointestinal tract may occasionally precede the appearance of the cutaneous lesions.
Eventually, most patients with epidemic KS develop disseminated disease. The disease often progresses in an orderly fashion from a few localized or widespread mucocutaneous lesions to more numerous lesions and generalized skin disease with lymph node, gastrointestinal tract disease, and other organ involvement. Pleuropulmonary KS is an ominous sign usually occurring late in the course of the disease, especially in those patients whose death is directly attributed to KS. Most patients with epidemic KS die of one or more complicating opportunistic infections.
The staging evaluation of patients with classic Kaposi sarcoma (KS) should be individualized. The advanced age of most of the patients, localized nature of the tumor, rarity of visceral involvement, and usually indolent course of the disease should temper the extent of the evaluation. A careful examination of the skin and lymph nodes is sufficient in most cases. For the rare patient with rapidly progressive tumor or signs or symptoms of visceral involvement, appropriate evaluation is indicated. No universally accepted classification is available for epidemic KS. Staging schemes that incorporate laboratory parameters as well as clinical features have been proposed. Since most patients with epidemic KS do not die from the disease, factors besides tumor burden are apparently involved in survival.
The conventions used to stage KS and the methods used to evaluate the benefits of KS treatment continue to evolve because of changes in the treatment of human immunodeficiency virus (HIV) and in recognition of deficiencies in standard tumor assessment. The clinical course of KS, the selection of treatment, and the response to treatment are heavily influenced by the degree of underlying immune dysfunction and opportunistic infections.
The AIDS Clinical Trials Group (ACTG) Oncology Committee has published criteria for the evaluation of epidemic KS. The staging system incorporates measures of extent of disease, severity of immunodeficiency, and presence of systemic symptoms. As shown in Table 1 below, the ACTG criteria categorizes the extent of the tumor as localized or disseminated, the CD4 cell number as high or low, and a systemic illness as absent or present.
A subsequent prospective analysis of 294 patients entered on ACTG trials for KS between 1989 and 1995 showed that each of the tumor, immune system, and systemic illness variables was independently associated with survival. Multivariate analysis showed that immune system impairment was the most important single predictor of survival. In patients with relatively high CD4 counts, tumor stage was predictive. A CD4 count of 150 cells/mm³ may be a better discriminator than the published cutoff of 200 cells/mm³. A study is in progress to determine if viral load adds predictive information. None of the prior studies were conducted at a time when combined antiretroviral therapy (cART) was readily available. The impact of cART on survival in KS requires continued assessment.
Classic Kaposi sarcoma (KS) usually is limited to the skin and has an indolent course. Patients with this tumor are predisposed to the development of a second primary malignancy, and the treating physician should consider this factor when arranging a schedule of follow-up treatment for the patient.
Equivalent standard treatment options:
Widespread skin disease:
EBRT used in this manner gave long-term results that were superior to those obtained with radiation therapy administered to successive individual lesions as they appeared.
One patient was treated repeatedly with intralesional injections of 0.25 to 0.50 mg of vincristine, which resulted in complete disappearance of the treated lesion. Multiple courses of therapy were required because of the recurrence of disease in untreated areas.
Electroporation of the skin lesions was combined with intravenous bleomycin for 19 patients with classical KS. Most patients responded after one application, the rest after two or three applications, with a median duration of response of 16 months.[Level of evidence: 3iiiDiv]
Lymph node and gastrointestinal tract involvement:
Current Clinical Trials
Use our advanced clinical trial search to find NCI-supported cancer clinical trials that are now enrolling patients. The search can be narrowed by location of the trial, type of treatment, name of the drug, and other criteria. General information about clinical trials is also available.
Some patients with Kaposi Sarcoma (KS) have noted spontaneous and lasting remissions following discontinuation of immunosuppressive therapy. In managing these patients, if immunosuppressive therapy is not critical, its discontinuation is a reasonable first step.
Standard treatment options:
Treatment may result:
No data are available, however, to show that treatment improves survival. In addition to antitumor treatment, essential components of an optimal Kaposi sarcoma (KS) treatment strategy include combined antiretroviral treatment (cART), prophylaxis for opportunistic infections, and rapid recognition and treatment of intercurrent infections.
Most good-risk patients, defined by the AIDS Clinical Trials Group as T0, show tumor regression with cART alone.[2,3,4] Poor-risk patients, defined as T1, usually require a combination of cART and chemotherapy with discontinuation of the chemotherapy after disappearance of the skin lesion.[2,3,4] The combination of cART and liposomal doxorubicin resulted in a 5-year overall survival (OS) rate of 85% in 140 patients with T1 disease.[Level of evidence: 3iiiDiv]
Small localized lesions of KS may be treated by electrodesiccation and curettage, cryotherapy, or by surgical excision. KS tumors are also generally very responsive to local radiation therapy, and excellent palliation has been obtained with doses at 20 Gy or slightly higher.[5,6,7] One report demonstrated a response rate higher than 90%, with a median time to progression of 21 months. Although no difference in response was noted with a variety of fractionation regimens, a single fraction of 8 Gy is indicated for cutaneous lesions and is associated with significantly fewer severe reactions. Radiation therapy is generally reserved to treat localized areas of the skin and oral cavity. It is less often used to control pulmonary, gastrointestinal tract, or other sites of KS lesions. Localized KS lesions have also been effectively treated with intralesional injections of vinblastine. Alitretinoin 0.1% gel provided local control in a randomized prospective multicenter trial.[Level of evidence: 1iiDiv]
In epidemic KS, the already profoundly depressed immunologic status of the host limits the therapeutic usefulness of systemic chemotherapy. Systemic chemotherapy studies in epidemic KS have used as single agents or in combinations doxorubicin, bleomycin, vinblastine, vincristine, etoposide, paclitaxel, and docetaxel.[11,12,13,14,15][Level of evidence: 3iiiDiv] The combination of cART and liposomal doxorubicin resulted in a 5-year OS of 85% in 140 patients with T1 disease.[Level of evidence: 3iiiDiv]
Randomized multicenter trials showed an improvement in response rate (45%-60% vs. 20%-25%) and a more favorable toxic effects profile for pegylated liposomal doxorubicin or liposomal daunorubicin, compared to the combination of doxorubicin, bleomycin, and vincristine or bleomycin and vincristine.[16,17,18][Level of evidence: 1iiDiv] During cART, both pegylated liposomal doxorubicin and paclitaxel are active single agents with response rates close to 50%.[Level of evidence: 1iiDiv]
Biologic and targeted therapy
The interferon alphas have also been widely studied and show a 40% objective response rate in patients with epidemic KS.[20,21] In these reports, the responses differed significantly according to the prognostic factors of extent of disease, prior or coexistent opportunistic infections, prior treatment with chemotherapy, CD4 lymphocyte counts lower than 200 cells/mm³, the presence of circulating acid-labile interferon alpha, and an increase in beta-2-microglobulin. Several treatment studies have combined interferon alpha with other chemotherapeutic agents. Overall, these trials have shown no benefit with the interferon-chemotherapy combinations as compared to the single-agent activities.
Recombinant interferon alpha-2a and interferon alpha-2b were the first agents approved for the treatment of KS. Approval was based on single-agent studies performed in the 1980s before the advent of antiretroviral therapy. The early studies demonstrated improved efficacy at relatively high doses. High-dose monotherapy is rarely used today, and instead, interferon is given in combination with other anti-HIV drugs in doses of 4 to 18 million units. Neutropenia is dose limiting, and trials of doses of 1 to 10 million units combined with less myelosuppressive antiretrovirals are in progress. Response to interferon is slow, and the maximum effect is seen after 6 or more months. Interferon should probably not be used in the treatment of patients with rapidly progressive, symptomatic KS.
Imatinib, a c-kit/PDGF (platelet-derived growth factor) receptor inhibitor, resulted in partial responses in 10 of 30 previously treated patients (cART + chemotherapy).
Bevacizumab, the humanized, antivascular, endothelial growth-factor monoclonal antibody, had a response rate in 5 of 16 patients who did not improve after the institution of cART and chemotherapy.[Level of evidence: 3iiiDiv]
Interleukin-12 had a response rate of 71% (95% confidence interval, 48%-89%) among 24 evaluable patients in a phase I and phase II trial.[Level of evidence: 3iiiDiv]
Treatment options under clinical evaluation:
The prognosis for any treated Kaposi sarcoma patient with progressing, recurring, or relapsing disease is highly variable. Deciding on further treatment depends on many factors, most importantly the clinical setting (i.e., classic, immunosuppressive treatment, or AIDS) in which the tumor arises as well as individual patient considerations.
Clinical trials are appropriate and should be considered when possible.
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Editorial changes were made to this summary.
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Purpose of This Summary
This PDQ cancer information summary for health professionals provides comprehensive, peer-reviewed, evidence-based information about the treatment of Kaposi sarcoma. It is intended as a resource to inform and assist clinicians who care for cancer patients. It does not provide formal guidelines or recommendations for making health care decisions.
Reviewers and Updates
This summary is reviewed regularly and updated as necessary by the PDQ Adult Treatment Editorial Board, which is editorially independent of the National Cancer Institute (NCI). The summary reflects an independent review of the literature and does not represent a policy statement of NCI or the National Institutes of Health (NIH).
Board members review recently published articles each month to determine whether an article should:
Changes to the summaries are made through a consensus process in which Board members evaluate the strength of the evidence in the published articles and determine how the article should be included in the summary.
The lead reviewers for Kaposi Sarcoma Treatment are:
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PDQ® Adult Treatment Editorial Board. PDQ Kaposi Sarcoma Treatment. Bethesda, MD: National Cancer Institute. Updated <MM/DD/YYYY>. Available at: https://www.cancer.gov/types/soft-tissue-sarcoma/hp/kaposi-treatment-pdq. Accessed <MM/DD/YYYY>. [PMID: 26389335]
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Last Revised: 2018-01-30
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