Splenic irradiation as management of ITP.

Abstract

The management of haematological diseases in Jehovah's witnesses is usually complicated. We recently cared for a patient with severe chronic idiopathic thrombocytopenic purpura (ITP) in whom splenectomy was deemed necessary to control his disease (Okerbloom et al, 1996). Based on two previous articles (Calverley et al, 1992; Caulier et al, 1995) reporting good results with splenic irradiation in patients either old or with contraindications for surgery, we decided to use radiation therapy as a means of preparing a risky candidate for a splenectomy. A 23-year-old man, a Jehovah's witness, was admitted in February 1998 with a relapse of chronic ITP. The patient had the first episode at age 12 and it did not recur until November 1997, when he developed purpura, petechiae and mucusal bleeding with a platelet count of 3 × 109/l. He was placed on steroids which produced no rise in the platelet count. A week later a pulse of intravenous globulin (IVIgG) was given with an excellent response lasting 5 weeks, but falling precipitously to 1 × 109/l with recurrence of the bleeding diathesis. This prompted the current crisis, when he was treated with prednisone 120 mg and a 5 d course of IVIgG (see Fig 1, week 11), the latter being repeated 3 weeks later and followed by a 4 d course of dexamethasone 40 mg. Because the patients platelet count had been 10 × 109/l for 4 weeks, with the maximal response after 6 weeks of full therapy of 18 × 109/l, and as minor bleeding diathesis still persisted, we felt splenectomy was indicated. . Clinical course of a patient with refractory ITP. Surgery was considered too risky for someone refusing blood component replacement and taking the reported experiences on patients with unacceptable surgical risks into account, splenic irradiation was carried out. A total dose of 15 Gy was administered over 5 consecutive days (300 cGy/d via two, anterior and posterior opposite fields). One week later the platelet count was 110 × 109/l and splenectomy was uneventfully carried out after another week. Three weeks later the platelet count had further risen to 420 × 109/l and has remained stable around this level without any other treatment, for the ensuing 10 months. Splenic radiation has been used as an alternative to splenectomy in patients with corticosteroid-resistant immune thrombocytopenia and contraindications to surgery. In the combined series (Calverley et al, 1992; Caulier et al, 1995), 9/21 patients (47%) had good early responses with a rise in the platelet count >50 × 109/l, which can be considered as a relatively safe threshold for this type of surgical intervention. Most responses lasted for >6 months. Low-dose splenic irradiation has not been associated with acute or long-term side-effects, since the radiation tolerance of the kidney and colon are well above the doses used, but a proportion of patients in whom splenectomy was subsequently required had varying degrees of adhesion formation between the spleen and the surrounding tissues at laparotomy (Calverly et al, 1992). The radiation dose has varied widely. Calverley et al (1992) predominantly used a 600 cGy total dose, in six doses over 3 weeks without renal shielding, whereas Caulier et al (1995) used 1500 cGy in 5 weeks (2-weekly 150 cGy doses), shielding the left kidney but leaving 20–25% of the splenic volume undertreated. It is worth noting the speed of the platelet response: in our patient, 7 d after the start of radiotherapy the platelet count had increased from 18 to 110 × 109/l. Likewise, responses were observed as early as 4 weeks from the start of radiotherapy (Calverley et al, 1992). It is also worth mentioning that using radiation as an immediate preoperative treatment, one should avoid adhesion formation between the spleen and the surrounding tissues found when splenectomy is performed later (in 3/6; Calverley et al, 1992). In high-risk situations such as the one we report, a short course of splenic radiation can rapidly increase the platelet found to safe levels, and thus reduce the risks associated with splenectomy.