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Sixty-one consecutive patients undergoing splenectomy for chronic immune thrombocytopenia were retrospectively evaluated. Platelet response was considered as complete (CR) when platelet count rose to > 100 × 109/l, partial (PR) when 30–100 × 109/l or absent (NR) if otherwise. Follow-up (mean time 7·6 years) was possible in 54 patients. Forty-eight patients (88%) had an immediate response to splenectomy (39 CR, 9 PR) whereas six (12%) were NR. Thirty-six responders (67%) had sustained remission (31 CR; 5 PR) without further treatment; thrombocytopenia recurred in 12 patients (33%). The probability curve of continued remission showed a constant relapse-rate during the first 36 months; a further step of relapse was observed beginning 70 months after surgery. The only positive predictive factor for the long-term response to splenectomy was age < 40 (P < 0·005). Neither duration of thrombocytopenia nor previous response to medical treatment (steroids and/or intravenous immunoglobulins) were related to splenectomy response.
Thrombocytopenia is commonly encountered in clinical practice with an estimated incidence of 4·5 per 100 000 in men and 7·4 in women. About 50% of cases are the result of autoantibodies against platelet and megakaryocyte surface antigens (McMillan & Imbach, 1994).
The acute form of immune thrombocytopenic purpura (ITP) occurs more frequently in childhood and is self-limiting in more than 70% of cases, whereas chronic ITP occurs mainly in adults ( McMillan & Imbach, 1994; George et al, 1996).
The therapeutic strategies in ITP include: (a) treatment of acute bleeding episodes; (b) long-term improvement in platelet count; and (c) potentially definitive cure of the disease. Because few chronic ITP patients achieve remission with medical therapy, splenectomy is the corner-stone treatment (George et al, 1996). However, there is no definitive evidence concerning the optimal timing for splenectomy, nor about the related prognostic factors of response or long-term outcome. We retrospectively analysed the clinical response to splenectomy in 61 patients with chronic ITP belonging to a larger cohort of 200 consecutive patients treated at our clinics.
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Chronic ITP in elderly patients usually has an insidious onset and a prolonged benign course with only minor bleeding manifestations such as purpura, petechiae, epistaxis and gingival oozing. Therefore, in the absence of surgery or risk factors, patients should be treated only when platelet count is lower than 30 × 109/l or in the presence of major haemorrhage (George et al, 1996).
Steroids increase platelet count in more than 50% of patients, but complete remission of thrombocytopenia is obtained only in a few (McMillan & Imbach, 1994; George et al, 1996;) who would probably have done well spontaneously. Patients who are refractory, or responsive only to high-dose steroids or complain of severe side-effects of medical therapy, are candidates for splenectomy. However, there is no evidence-based consensus about the optimal timing for surgery. Our patients underwent late splenectomy in agreement to the presently prevailing opinion among American haematologists (George, 2000). Accordingly, the rationale for late surgery was good tolerance to low platelet count, the possibility of spontaneous remission and the concern of life-threatening infections after splenectomy. The results from several studies published in recent years indicate no difference in outcome between early (< 12 months from onset) (Mazzucconi et al, 1999) and late surgery (Fenaux et al, 1989; Stasi et al, 1995).
Splenectomy has been successful in about 80% of patients, consistent with the fact that the spleen is the predominant site for both autoantibody production and platelet destruction (Gernsheimer et al, 1989).
In keeping with such data, an initial response to splenectomy of 87% was observed in our series. However, 25% of our patients relapsed, a slightly higher percentage than reported elsewhere (Pizzuto & Ambritz, 1984; Fenaux et al, 1989; Stasi et al, 1995). Such a discrepancy can be explained by the threshold of 30 × 109/l platelets to define response and the longer follow-up in our series, suggesting a time relationship for response rate. In fact, the probability of remission at 120 months was similar to that reported in another long-term study (Stasi et al, 1995), however we observed more late relapses.
We analysed the prognostic value of age, sex, severe haemorrhages and platelet count at diagnosis, duration of thrombocytopenia and the response to medical therapy. Our data support the role of positive predictive factor for long-term response to splenectomy for young age and severe bleeding only. Major haemorrhages were also confirmed to be age related, as reported by Cortellazzo et al (1991). The relationship between IVGG and splenectomy response was not statistically significant because patients refractory to IVGG still had a good chance of responding to splenectomy (Fabris et al, 1997).
In conclusion, splenectomy is an effective treatment for chronic ITP but the response rate decreases with time. Choosing splenectomy for ITP treatment requires individual case analysis because only young age seems to be a predictive factor for a good response.