Evidence-Based Mini-Review: Is Indium-Labeled Autologous Platelet Scanning Predictive of Response to Splenectomy in Patients With Chronic Immune Thrombocytopenia?

Abstract

Clinical scenario: An otherwise healthy 25-year-old woman returns to your office for management of chronic primary immune thrombocytopenia. She was diagnosed 6 months earlier and continues to require prednisone 15 mg daily and periodic infusions of intravenous immunoglobulin to maintain a hemostatic platelet count. You discuss second-line treatment options, including splenectomy. The patient asks if there are any means by which to predict likelihood of response to splenectomy. You have heard about the use of indium-labeled autologous platelet scanning for this purpose and wonder what the evidence shows.Immune thrombocytopenia (ITP) comprises a heterogeneous group of disorders characterized by autoimmune-mediated platelet destruction by tissue macrophages in the spleen and elsewhere, variable impairment of thrombopoiesis, and an elevated risk of bleeding. Splenectomy remains a highly effective and well-tolerated treatment for patients refractory to or intolerant of first-line therapy with long-term complete response rates of 66%. 1-3 Nevertheless, splenectomy is not without its drawbacks, including complications related to surgery and anesthesia in the short-term and lifelong risks of serious infection and possibly thromboembolism. 2 Indium-labeled autologous platelet scanning (ILAPS) is a nuclear imaging modality in which autologous platelets are reinfused into the patient after ex vivo labeling with 111 In. Subsequent scintigraphy demonstrates the site(s) of platelet sequestration and clearance. It has been proposed that patients with purely or predominantly splenic sequestration determined by ILAPS may be more likely to respond to splenectomy than those exhibiting hepatic, mixed, or diffuse patterns. 4 To evaluate the potential of ILAPS to predict response to splenectomy, we performed a comprehensive literature review of all studies in which ILAPS was performed prior to splenectomy in patients with ITP.A search of the PubMed database limited to English language references was conducted by combining the MeSH (Medical Subject Heading) term "indium" with the keywords "ITP," "immune thrombocytopenic purpura," "idiopathic thrombocytopenic purpura," and "autoimmune thrombocytopenia" between 1950 and June 30, 2010. This strategy yielded 51 citations. Excluded were 32 studies in which either ILAPS or splenectomy was not performed, 6 case reports, and 3 reviews. Of the 10 remaining references, 1 did not include data on response to splenectomy, 1 did not provide information on the sequestration pattern observed with ILAPS, and 3 were preliminary reports of ongoing case series for which updated iterations have been published, leaving 5 eligible studies. 5-9 A search of abstracts from the American Society of Hematology, the International Society on Thrombosis and Haemostasis, and the European Haematology Association since 2003 identified a sixth eligible study (n ϭ 580 for all eligible studies). A manuscript describing this study was in press at the time of our literature search and was graciously provided by the authors ...

Splenectomy as a curative treatment for immune thrombocytopenia: a retrospective analysis of 233 patients with a minimum follow up of 10 years

“…In this regard, other prognostic parameters should be explored before splenectomy, particularly radio-labeled platelet scans. 23,24 The analysis of the 95 patients (41%) who did not achieve a stable response showed that, despite most of them needing multiple lines of further treatments, a new response was achieved in 83% of the cases, confirming that splenectomy can convert refractory patients into responding ones, and does not exclude the possibility of a second response in relapsing patients. 19,20 Indeed, only 16 patients (7%) did not respond to any further treatment and only 3 (1%) died of bleeding complications.…”

How we manage immune thrombocytopenia in the elderly

“…Before considering splenectomy, we must evaluate comorbidities and life expectancy, and we usually perform an isotopic platelet lifespan study even though the value of platelet scan is debatable and its availability limited (Cuker & Cines, 2010). The number of patients reluctant to undergo splenectomy is increasing (Michel et al, 2015a) but predominant destruction of platelets in the spleen could be a strong argument for splenectomy, mainly in a 65-year-old patient with no co-morbidities and favourable ASA status.…”

How I treat immune thrombocytopenia: the choice between splenectomy or a medical therapy as a second-line treatment

“…Recommendations would be influenced by the results of platelet isotopic distribution studies (if confirmed and if available). 51 At the other end of the spectrum, we try to avoid splenectomy in patients over 65-70 years of age (depending on their physical condition) not only because of higher complication rates but also because of lower response rates. The same considerations apply to the very frail, those with significant surgical comorbidities, history or risk of thrombosis, those with obligatory exposure to malaria or babesia, or those who have secondary ITP.…”