The role of radiation therapy in the management of HIV-related Kaposi's sarcoma

Pathologic Angiogenesis of Malignant Vascular Sarcomas: Implications for Treatment

Angiosarcoma, epithelioid hemangioendothelioma, and Kaposi sarcoma are classified according to the line of differentiation that these neoplastic cells most closely resemble: the endothelial cell. Although these malignant vascular sarcomas demonstrate immunohistochemical and ultrastructural features typical of this lineage, they vary dramatically in presentation and behavior, reflecting oncologic mechanisms unique to each. Antineoplastic therapies offer significant benefit, but because of the rarity of these cancers, novel therapies are slow to develop, and treatment options for these cancers remain limited. Antiangiogenic approaches that have shown benefit in other malignancies have not fully realized their promise in vascular tumors, suggesting that these tumors do not depend entirely on either angiogenic growth factors or on neighboring endothelia that are affected by these agents. Nonetheless, translational studies have begun to unravel these distinct pathologies, identifying novel translocation products, targets of oncogenic virulence factors, and genomic mutations that hijack angiogenic signaling and drive malignant growth. Concurrently, an elaborate and highly regulated model of angiogenesis and lymphangiogenesis involving vascular endothelial growth factor–receptor tyrosine kinase and TGF-β and Notch pathways has emerged that informs treatment of these tumors as well as cancer in general. This review summarizes the literature on malignant vascular sarcomas in the context of current models of angiogenesis and, in light of recent clinical trial data, could help clinician-scientists generate novel therapeutic approaches.

Acquired immunodeficiency syndrome related Kaposi's sarcoma eroding the maxillary bone

BACKGROUND

Oral involvement is a common manifestation of acquired immunodeficiency syndrome related Kaposi's sarcoma, and it occurs in approximately one-third of afflicted patients.

METHODS

We report an unusual case of Kaposi's sarcoma of the hard palate which invaded the underlying maxillary bone.

RESULTS

The patient underwent excisional biopsy and was subsequently treated with localised radiation and systemic chemotherapy including liposomal doxorubicin.

CONCLUSIONS

The presentation, differential diagnosis, radiographic appearance and management of this serious complication are discussed. Our case highlights the need for a multidisciplinary approach, consisting of ENT, oncology and infectious disease consultation, to ensure appropriate management of maxillofacial, intraosseous, acquired immunodeficiency syndrome related Kaposi's sarcoma.

Management of AIDS-related Kaposi's sarcoma

The advent of highly active antiretroviral therapy (HAART) has lead to a substantial reduction in the prevalence, morbidity, and mortality associated with AIDS-related Kaposi's sarcoma. Similarly, concomitant advances in chemotherapy and supportive-care protocols have allowed for Kaposi's sarcoma to be managed more effectively in comparison with the pre-HAART era. Furthermore, developments in our understanding of the pathogenesis of Kaposi's sarcoma have identified several molecular targets that can potentially provide new therapeutic strategies. This Review discusses the role of conventional chemotherapeutic and immunomodulatory agents in the treatment of Kaposi's sarcoma and summarises the current status and future prospects of novel molecularly targeted agents in the treatment of this disease.

Novel pharmacological therapies for the treatment of AIDS-related Kaposi’s sarcoma

Kaposi's sarcoma (KS) is the most common cancer associated with AIDS. KS aetiology and pathogenesis are still poorly defined and no definitive treatment has yet been identified. However, the introduction in 1996 of highly active antiretroviral therapy as a standard of care for those infected with HIV-1 determined a strong protection against the development of opportunistic infections, as well as a remission of pre-existing complications, including KS. Under highly active antiretroviral therapy, KS in particular has shown the highest clinical response rate reported to date among AIDS patients. Furthermore, recent insights into the pathogenetic mechanisms involved in KS development have provided new hope for a response and improved survival in patients with AIDS-related KS. This paper presents an overview of the current knowledge concerning pharmacological approaches to treating this disease. Newer treatments such as PEGylated liposomal anthracyclin, paclitaxel and pathogenesis-based strategies are also discussed.

Clinical presentations and standard therapy of AIDS-associated Kaposi's sarcoma

The treatment plan for a patient with AIDS-related KS should be based on tumor characteristics, control of HIV infection, comorbidities, and patient treatment goals (see Table 1). Institution of optimal antiretroviral therapy is an essential component of KS therapy. When available, enrollment in a clinical trial should be considered, except for patients who are naive to chemotherapy with symptomatic or life-threatening KS. For a patient with minimal, indolent cutaneous disease, after optimal control of HIV replication, local treatment, investigational treatment, or interferon are reasonable considerations. For the patient with rapidly progressive, cutaneous disease, tumor-related symptoms, or visceral disease, cytotoxic chemotherapy in combination with antiretroviral therapy is the first consideration. Future advances undoubtedly will include pathogenesis-based agents, either alone or in combination with currently available cytotoxic therapy.

Management of AIDS-related Kaposi's sarcoma: advances in target discovery and treatment

Kaposi's sarcoma is the most common tumor arising in HIV-infected patients and is an AIDS-defining illness by the Centers for Disease Control guidelines. Recent advances in the elucidation of the pathogenesis of KS are uncovering potential targets for KS therapies. Such targets include the processes of angiogenesis and cellular differentiation and the Kaposi's sarcoma herpesvirus/human herpesvirus-8. With the increasing recognition that effective antiretroviral regimens are associated with both a decreased proportion of new AIDS-defining Kaposi's sarcoma cases and a regression in the size of existing Kaposi's sarcoma lesions, most, if not all, Kaposi's sarcoma patients should be advised to take antiretroviral drugs that will maximally decrease HIV-1 viral load. Five agents are currently approved by the US FDA for the treatment of Kaposi's sarcoma; alitretinoin gel for topical administration; and liposomal daunorubicin, liposomal doxorubicin, paclitaxel and interferon-alpha for systemic administration. Many more agents, particularly angiogenesis inhibitors and other pathogenesis-targeted therapies are in early clinical development. Over the next 5 years, we may see even more of these pathogenesis-targeted therapies in trials and just as important we may identify, develop and validate clinically practical tools for assessing the biological effects of these therapies. The next 5 years may also bring a better understanding of the pharmacokinetic interactions among the many agents in the Kaposi's sarcoma and AIDS armamentariums.

New therapies for the treatment of AIDS-related Kaposi sarcoma

Kaposi sarcoma (KS) is the most common tumor arising in HIV-infected patients and is an AIDS-defining illness by the Centers for Disease Control guidelines. The clinical course of AIDS-related KS is highly variable, ranging from minimal stable disease to explosive growth. Recent advances in the elucidation of the pathogenesis of KS are uncovering many potential targets for KS therapies. Such targets include the processes of angiogenesis and cellular differentiation, sex hormones, and the KS herpesvirus/human herpesvirus-8. With the increasing recognition that effective antiretroviral regimens are associated with both a decreased proportion of new AIDS-defining KS cases and a regression in the size of existing KS lesions, most, if not all, KS patients should be advised to take antiretroviral drugs that will maximally decrease HIV-1 viral load. Five agents are currently approved by the Food and Drug Administration for the treatment of KS: alitretinoin gel for topical administration; and liposomal daunorubicin, liposomal doxorubicin, paclitaxel, and interferon-alpha for systemic administration. Many more agents, particularly angiogenesis inhibitors, are in early clinical development. The potential interaction between anti-KS agents and antiretroviral agents needs to be kept in mind. Virtually all patients with KS can derive benefit from the many approved and investigational agents developed through years of collaborative translational and clinical research.

The epidemiologic, pathologic, and clinical features of AIDS-associated pulmonary Kaposi's sarcoma

AIDS-related Kaposi's sarcoma (KS) occurs principally in homosexual or bisexual men infected with the newly identified human herpes virus-8, also called KS-associated herpes virus. Unlike classical forms of the disease, AIDS-associated KS is a multicentric entity that frequently involves lymph nodes and the GI tract. KS may also occur in the lung, commonly in the setting of extensive mucocutaneous disease and very rarely as an isolated event. The exact incidence of intrathoracic KS in patients with AIDS is unknown. Before the advent of highly active antiretroviral therapy (HAART), pulmonary KS had been reported in approximately 10% of patients with AIDS, 25% of patients with cutaneous KS, and in roughly 50% of postmortem examinations of patients with AIDS, KS, and respiratory infections. In the HAART era, the incidence of KS has declined precipitously in North America and Europe but not in third world countries where HAART is largely unavailable. Pulmonary KS may cause radiographic infiltrates and respiratory symptoms that mimic a variety of other infectious and neoplastic processes. An aggressive diagnostic evaluation of patients who have this condition is essential because chemotherapy and radiation therapy may provide significant palliation, particularly if used in conjunction with HAART. This review briefly explores the changing epidemiology of KS. The pathology and pathogenesis of KS is also reviewed, along with the clinical and radiographic presentation, diagnosis, and management of pulmonary KS.

Acquired immune deficiency syndrome-related hyperkeratotic Kaposi's sarcoma with severe lymphoedema: report of five cases

Kaposi's sarcoma (KS) is the most frequent neoplasm in acquired immune deficiency syndrome (AIDS) patients. Whereas typical cases present as erythematous, plaque or nodular lesions, hyperkeratotic variants of AIDS-associated KS are rare. We describe five patients with AIDS-associated KS with hyperkeratosis and lymphoedema as prominent features. We also speculate on its pathogenesis.

Palliative treatment of epidemic Kaposi sarcoma of the feet

Limited information is available in the medical literature on epidemic Kaposi sarcoma (EKS) of the foot. Patients with EKS of the foot can experience severe discomfort that makes it difficult to ambulate and even wear shoes. Between 1985 and 1996, 36 patients with EKS of the foot were treated with palliative intent. Most patients were referred for radiation therapy because of foot discomfort or marked difficulty with ambulation. From the pool of 36 patients, data were available at completion of treatment for 46 sites, and at 1 month for 44 sites. Morbidity was assessed for 35 sites. The median follow-up time for the 44 sites with at least 1 month follow-up was 8 months. The most frequently used regimen was a novel fractionation schedule of three fractions a week at 3.5 Gy/fx to a total dose of 21.0 Gy. The overall response rate and complete response rate for the 44 sites with at least 1 month follow-up were 91% and 80%, respectively. The 46 treated sites evaluated at the completion of treatment had a complete response rate of only 13% and an overall response rate of 63%. Of the 35 sites assessed for acute toxicity, 63% experienced discomfort related to the radiation therapy. This discomfort usually resolved without intervention within 2 weeks of completion of radiation therapy. For patients with and without a history of opportunistic infections, complete responses were observed in 8 of 12 sites (67%) and 25 of 27 sites (93%), respectively (p = 0.06). Radiation therapy for EKS of the foot yields excellent response rates, comparable with responses seen in other cutaneous sites with EKS. Appropriate patient education and support are needed because initial responses to radiation therapy are often disappointing and pedal discomfort can be exacerbated transiently. However, the discomfort resolves and complete response occurs in most patients. The 3.5-Gy triweekly fractionation schedule is a convenient and effective regimen and minimizes treatment visits for patients with ambulatory discomfort. A history of opportunistic infections appears to be a poor prognosticator of response to radiation treatments.

Kaposi's sarcoma and human herpesvirus-8

KS is a major cause of morbidity and mortality among AIDS patients and a treatment problem in the sporadic cases that are not associated with HIV. All four forms of the disease are linked to a newly described herpesvirus, HHV-8 or KSHV, via strong epidemiologic associations and biologic plausibility as a causal agent. HHV-8 is also epidemiologically associated with body cavity-based lymphomas, which are almost unique to AIDS, and Castleman's disease. Existing radiation and chemotherapeutic treatments of KS are only partially effective and cause significant adverse effects. New preventive approaches and therapies aimed at inhibiting HHV-8 may be effective. New treatments that interfere with the molecular mechanisms that drive KS may, in the future, provide the best opportunities to control the disease.

Acquired immunodeficiency syndrome-associated Kaposi's sarcoma. Biology and management

Kaposi's Sarcoma (KS), the most common AIDS-associated malignancy, occurs with increased frequency in all HIV transmission groups, but at a particularly high rate in homosexual men. Recent studies suggest that KS pathogenesis involves exposure to an infectious agent, altered expression and response to cytokines, and modulation of growth by HIV gene products. KS varies in its clinical presentation from a relatively indolent process to a widely disseminated, aggressive disease. A variety of local and systemic treatments provide effective, but usually temporary, disease palliation. Insights into KS pathogenesis suggest a number of targeted therapeutic approaches that may eventually lead to improved disease management and disease cure.