Palliative Splenectomy for Myelofibrosis with Myeloid Metaplasia: Three Decades of Experience in 314 Patients.
Authors: Mesa Ruben A. , Schwager Susan , Nagorney David S. , Tefferi Ayalew 
Published: October 2019

Abstract
BACKGROUND: Our group has periodically analyzed (Silverstein et. al. JAMA1974;227(4):424 to Tefferi et. al. Blood2000;95(7):226) presentation, peri-operative and long-term outcomes from splenectomy for myelofibrosis with myeloid metaplasia (MMM) in an attempt to improve patient selection and management. We now report on an additional 91 patients (pts) to see if control of post splenectomy thrombocytosis, and modern techniques, have diminshed morbidity and mortality. Additionally, we provide long-term follow-up on prior cohorts across a twenty-eight year period.
METHODS: A comprehensive retrospective analysis of presentation, peri-operative and long-term outcomes in a single institution experience with splenectomy in pts with MMM from 1976–2004.
RESULTS:
Presplenectomy : 314 MMM pts (171 men 54%; 208 (66%) with agnogenic myeloid metaplasia) were included. Presplenectomy 55% of pts presented with a Lille MMM prognostic score of ≥1, 90 pts (29%) failed a prior therapy for splenomegaly and pre-operatively had median spleen size of 20cm below the left costal margin (95%CI 18.7–20.4).
Perioperative Outcomes : Pts were splenectomized (1976–1985 (Decade 1(D1)) (n=90 (29%)); 1986–1996 (D2) (n=133 (42%)); 1997–2004 (D3) (n=91 (29%)) a median of 27 months (range 0–389 months) after the diagnosis of MMM (age at diagnosis (median 65 (range 19–83)) with a median splenic mass 2700 gm (range 300–11750)). Primary indication for surgery included mechanical symptoms n=156 (49%), anemia n=78 (25%)), portal hypertension n=47 (15%), or thrombocytopenia n=33 (11%). Peri-operative complications occured in 103 pts (33%) and included infection (n=30), thrombosis (n=34), and bleeding (n=48; 37 required a second laparotomy) of which 28 (9% of all pts) were fatal (30 day mortality (D1=10%, D2=9%, D3=7.7% (p=NS)). Overall length of hospital stay (D3) was median of 8 days (range 3–63), during which 6 pts (7%) required platelet pheresis (1–8 times; for platelet counts of 870–2400 x 109/L) and/or acute platelet lowering agents (n=12; 13%), respectively. Additionally, median post-splenectomy increases in leukocyte and platelet count were 8 x 109/L (range −65 to 190.2) and 127 x 109/L (range −270 to 1221), respectively.
Long-Term Outcomes and Survival : Amongst the recent cohort (n=91) 69 pts (76%) experienced a palliative benefit for their primary surgical indication for a median of 12 months (range 1–91). Post splenectomy rates of thrombocytosis (21%), accelerated hepatomegaly (8%), and leukemic transformation (11%) did not vary across the three decades analyzed. Overall survival (n=263 (84%) have expired)) from the diagnosis of MMM and splenectomy was 62 months (95%CI 54–66) and 19 months (95%CI 14–22), respectively. Survival after splenectomy was not significantly different by type of MMM, surgical indication, Lille MMM prognostic score, leukemic transformation or decade performed. However, patients with preoperative thrombocytopenia (<50 x 109//L (p<0.0001) or <100 x 109/L (P=0.006)) clearly had a decrease in survival, although this was independent of the development of peri-operative complications.
CONCLUSIONS: Splenectomy for MMM remains a procedure with significant peri-operative risks, but potential for palliating symptoms. Decreased survival in thrombocytopenic pts probably arises from advanced disease as opposed to increased complications. The lack of improvement in overall post-splenectomy survival across the study period may not be attributable to peri-operative issues but a reflection on the failure of medical therapy to improve survival in MMM.