How is Kaposi sarcoma (KS) treated?

Updated: Apr 11, 2019
  • Author: Jessica Katz, MD, PhD, FACP; Chief Editor: Edwin Choy, MD, PhD  more...
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Answer

Currently, no treatment is available to eradicate HHV-8 infection. Therefore, there is no cure for Kaposi sarcoma (KS). Instead, the purpose of therapy in all forms of KS is directed at alleviating symptoms and slowing disease progression. Treatment decisions vary depending on KS form, presence of symptoms, and extent of disease.

Classic KS is usually limited to the skin and has an indolent course. A retrospective analysis of 123 patients with classic KS found that the median time to progression with observation alone was 4 months. However, multivariate analysis determined that immunosuppression was the only significant independent factor that predicted disease progression. Therefore, observation alone may be sufficient for immunocompetent asymptomatic patients. [78]  

Lower extremity edema can be managed with compression stockings. Local therapies, including surgical resection, radiotherapy, cryotherapy, and intralesional chemotherapy, can be used to treat symptomatic or cosmetically unacceptable lesions. Systemic chemotherapy should be reserved for patients in whom local therapy fails or who have extensive disease. [78]

Therapy for epidemic Kaposi sarcoma centers on the use of highly active antiretroviral therapy (HAART), which has decreased the incidence and severity of this disease. Most good-risk patients show tumor regression with HAART alone. Local therapies can also be implemented for symptomatic or cosmetically disfiguring cutaneous lesions.The least invasive and toxic modality should be used due to high risk for infectious complications in this population. Poor-risk patients usually require a combination of chemotherapy with HAART.  Treatment is typically continued until response plateau or unacceptable toxicity. 

Iatrogenic or post-transplantation Kaposi sarcoma commonly responds to reduction or discontinuation of immunosuppression. In one study, tapering of immunosuppressive therapy alone led to complete or partial KS regression in 9 of 20 patients. [79]  However, this approach may not always be feasible and can place patients at risk for graft rejection.

Several retrospective and prospective studies have shown a benefit of switching from calcineurin inhibitors (eg, cyclosporine, tacrolimus) to a mammalian target of rapamycin (mTOR) inhibitor, specifically sirolimus. Although the exact mechanism is not fully understood, sirolimus is thought to have a direct cytotoxic effect on KS tumor cells due to inhibition of vascular endothelial growth factor, Flk-1/KDR and phosphorylated Akt which are commonly upregulated in Kaposi sarcoma. [80]  As in other forms of KS, chemotherapy is commonly reserved for limited disease refractory to local therapy or in patients with disseminated disease.

Of note, the role for antiviral agents against herpes viruses (eg, foscarnet, ganciclovir,valganciclovir) is unclear. These agents usually are ineffective in Kaposi sarcoma, likely because the neoplastic spindle cells harbor a latent HHV-8 infection. However, a study in patients with AIDS and cytomegalovirus (CMV) retinitis found that oral or intravenous ganciclovir (which is approved for use in CMV infection) reduced the risk of Kaposi sarcoma. [81] Further studies are needed in this area. [31]  Activation of drugs by Kaposi sarcoma herpes virus (KSHV) kinases is an approach that needs further investigation. Also, the c-kit oncogene is up-regulated by KSHV and would be a rational target for blockade.

 A course of antiviral therapy with cidofovir or foscarnet may be considered if there is suspicion for other coexisting HHV-8–related diseases (eg, multicentric Castleman disease, primary effusion lymphoma). [82]


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