Assessing Clinical Outcomes in Patients Undergoing Splenectomy for Immune Thrombocytopenia: A Real World Perspective
Authors: Rabinovich Emma , Pradhan Kith , Davido Helen Tracy , Gali Radhika , Islam Iffath , Muscarella Peter , Billett Henny H. 
Published: November 2021

Abstract
Background:
Immune thrombocytopenia (ITP) is an acquired immune-mediated disorder characterized by frequent relapses. Splenectomy was considered an integral part of ITP therapy until the inception of newer agents, namely rituximab and thrombopoietin receptor agonists (TPO-RA) over the last 20 years. Recently the role and timing of splenectomy have become an area of debate. Studies regarding optimal predictors of response have not demonstrated reliable clinical or laboratory factors. We chose to evaluate the most recent practices and outcomes at Montefiore Medical Center to assess the role of splenectomy in ITP treatment in our diverse, real world patient population.
Methods:
We conducted a retrospective cohort study of patients who had undergone splenectomy for ITP at Montefiore between January 1, 2015 and July 1, 2021. Collected data included demographics, comorbidities, prior lines of treatment, and splenectomy outcomes. Outcome data included mortality and need for post-splenectomy treatment. Response rates were assessed by American Society of Hematology (ASH) guidelines.
Results:
The study population comprised 29 patients who underwent splenectomy for ITP as primary indication. Patients were 59% (N=17) female, with a median age of 45 years. Our multi-ethnic cohort included 11 (40%) Hispanic, 7 (24%) African American, and 6 (21%) Caucasian patients. Five patients chose not to specify. Significant comorbidities prior to undergoing surgery were present in 79% (N=23) of patients, with the average number being two. Of these, 41% (N=12) had a comorbid autoimmune condition. Two were HIV positive.
Initial treatment consisted of steroids, IVIG (or WinRho), or both for all patients. Only four patients failed to respond to these therapies; one of whom experienced remission following splenectomy and one of whom expired within 30 days of surgery. Fourteen patients (48%) continued to receive repeat doses of steroids and/or IVIG until surgery. Time to splenectomy was variable, range 0-9 years. Additional therapy following relapse on initial treatment consisted of TPO-RA (11/29, 38%); rituximab (11/29, 38%); immunosuppressive therapy (1/29, 3%); and danazol (3/29, 10%). Response rates for TPO-RA (8/11, 73%), danazol (2/3, 67%), and immunosuppressive therapy (1/1) were greater than that for rituximab infusion (4/11, 36%). Overall, the average number of unique lines of therapy was 2.8 (median=2) and average years from diagnosis to splenectomy was 2.8 (median=1, range 0-11).
At a median time from splenectomy to last follow up (or time of death) of 971 days (median=876 days), 18 patients (62.1%) had remained off medical therapy with complete response (CR) following splenectomy. Three patients (10.3%) transiently required additional therapy but subsequently achieved CR and remained off medical therapy for greater than a year. Six patients (20.7%) continued to rely on medical therapy. Two patients (6.9%) died within 30 days of splenectomy; one of unknown causes and one of pulmonary embolism (despite thromboprophylaxis) in the setting of TPO-RA therapy. There was no difference in continued reliance on medical therapy in patients who underwent splenectomy earlier versus later in their ITP course. No differences in outcomes were noted in patients with underlying comorbidities. No differences in outcome were noted between Hispanic, African American, and Caucasian patients.
Conclusion:
Our review of ITP splenectomies in a real world patient population revealed significant differences in treatment practices and timing of surgical intervention. We did not note differences in splenectomy outcomes across patients of different backgrounds or with comorbidities, confirming that these should not play a role in treatment decisions. Patients who failed to respond to steroids and/or IVIG had lower response rates to splenectomy as has been previously hypothesized, though these represented a very small subset of our study population. Further evaluation of compliance, tolerance, and social factors (i.e. insurance, etc) may assist with understanding differences in response rates to various second line medical therapies. Splenectomy continues to offer high rates of sustained CR for a variety of patients, though reliable predictors of response remain elusive and should continue to be an area of active research.

Disclosures
No relevant conflicts of interest to declare.