Topical treatment of cutaneous Kaposi sarcoma with imiquimod 5% in renal-transplant recipients: a clinicopathological observation

Abstract

Kaposi sarcoma (KS) is a vascular neoplasm pathogenetically linked to human herpesvirus 8. Transplant recipients, in particular renal-transplant recipients (RTRs) are at higher risk for post-transplant (P)-KS which affects 0.2-11% of RTRs. The course of P-KS is influenced by the post-transplantation immunosuppressive treatment. Reduction of immunosuppressive drugs can result in tumour regression, and is the treatment of choice for P-KS, but is associated with the risk for transplant rejection. Imiquimod is a topically applied immunomodulator without relevant systemic absorption, and may thus represent a promising treatment for cutaneous KS in RTRs. The aim of this study was to investigate the clinical and histological effects of imiquimod in two RTRs with cutaneous KS. Imiquimod resulted in complete clinical and histologically proven remission in one patient, but in the second patient, although there was clinical remission, histological persistence of KS was found. Imiquimod may represent an effective treatment for RTRs with cutaneous P-KS. However, clinical remission does not necessarily indicate complete tumour regression, as shown in one of our patients, who had a persisting tumour, as shown by biopsy examination. Thus, histological confirmation is crucial to confirm complete response.

Diagnosis and Treatment of Kaposi Sarcoma

“…If this reactivation leads to virus release, this in turn may stimulate tissue and tumor-resident antigen presenting cells [125]. At this point several cases of skin KS responding to topical treatment with imiquimod have been published, as have been treatment failures [126–128]. A systemic clinical trial has not been conducted.…”

Imiquimod in dermatology: an overview

“…Since an initial report showing imiquimod's potential in accelerating infantile hemangioma (IH) regression, more evidence have emerged on the efficacy of imiquimod in the treatment of several cutaneous vascular tumors or disorders including Kaposi's sarcoma (KS), pyogenic granuloma, among others . Imiquimod‐induced regression of vascular tumors is probably mediated by its immunomodulatory and anti‐angiogenic effects…”

“…In addition, several case reports describe imiquimod's efficacy in treating KS in immunocompetent as well as immunosuppressed individuals, including HIV-positive patients. [120][121][122] Thus, the evidence for efficacy of imiquimod in KS treatment is of low quality.…”

Trial watch: FDA-approved Toll-like receptor agonists for cancer therapy

“…In the vast majority of cases, these approaches (including large, randomized trials as well as case studies) focused on conditions for which the topical application of imiquimod alone would be appropriate, encompassing infantile hemangiomas, 244 - 248 dysplastic nevi and in situ melanoma (lentigo maligna), 249 - 258 in situ squamous cell carcinoma (Bowen's disease) 259 - 264 keratoacanthoma, 265 - 267 non-genital warts, 268 - 272 xeroderma pigmentosum, 273 vulvar, vaginal and cervical intraepithelial dysplasia/neoplasia, 274 - 284 extramammary Paget's disease, 285 - 289 Kaposi's sarcoma, 290 - 292 desmoplastic trichoepithelioma (an uncommon adnexal tumor usually found on the face of young women), 293 cutaneous T-cell lymphoma, 294 - 296 as well as cutaneous metastases from multiple primary tumors 297 - 301 . In addition, a few groups have evaluated the therapeutic potential of imiquimod as an adjuvant to peptide- or cell-based anticancer vaccines 302 - 305 .…”