Clinical features and course of refractory anemia with ring sideroblasts associated with marked thrombocytosis

Background

Refractory anemia with ring sideroblasts associated with marked thrombocytosis was proposed as a provisional entity in the 2001 World Health Organization classification of myeloid neoplasms and also in the 2008 version, but its existence as a single entity is contested. We wish to define the clinical features of this rare myelodysplastic/myeloproliferative neoplasm and to compare its clinical outcome with that of refractory anemia with ring sideroblasts and essential thrombocythemia.

Design and Methods

We conducted a collaborative retrospective study across Europe. Our database included 200 patients diagnosed with refractory anemia with ring sideroblasts and marked thrombocytosis. For each of these patients, each patient diagnosed with refractory anemia with ring sideroblasts was matched for age and sex. At the same time, a cohort of 454 patients with essential thrombocythemia was used to compare outcomes of the two diseases.

Results

In patients with refractory anemia with ring sideroblasts and marked thrombocytosis, depending on the Janus Kinase 2 V617F mutational status (positive or negative) or platelet threshold (over or below 600×10⁹/L), no difference in survival was noted. However, these patients had shorter overall survival and leukemia-free survival with a lower risk of thrombotic complications than did patients with essential thrombocythemia (P<0.001) but better survival (P<0.001) and a higher risk of thrombosis (P=0.039) than patients with refractory anemia with ring sideroblasts.

Conclusions

The clinical course of refractory anemia with ring sideroblasts and marked thrombocytosis is better than that of refractory anemia with ring sideroblasts and worse than that of essential thrombocythemia. The higher risk of thrombotic events in this disorder suggests that anti-platelet therapy might be considered in this subset of patients. From a clinical point of view, it appears to be important to consider refractory anemia with ring sideroblasts and marked thrombocytosis as a distinct entity.     

Therapy-related myeloid neoplasms following treatment with radioiodine

Background

Few data are available on therapy-related myelodysplastic syndromes and acute myeloid leukemia developing after radioiodine treatment.

Design and Methods

We retrospectively analyzed 39 patients with myeloid neoplasms following radioiodine treatment, whose data were reported to the Duesseldorf Myelodysplastic Syndromes Register (8 of 3814 patients) and five other German Myelodysplastic Syndromes centers (n=31) between 1982 and 2011. These data were compared with those from 165 patients from our Myelodysplastic Syndromes Register with therapy-related myeloid neoplasms following chemotherapy (n=90), radiation (n=30), or radiochemotherapy (n=45).

Results

With a median latency of 79 months, 18 patients developed therapy-related acute myeloid leukemia and 21 presented with therapy-related myelodysplastic syndromes (8 refractory anemia with excess blasts I/II, 6 refractory anemia with multilineage dysplasia, 3 myelodysplastic syndromes with del(5q), 1 refractory anemia, 1 refractory anemia with ring sideroblasts, 1 chronic myelomonocytic leukemia II, 1 myelodysplastic/myeloproliferative neoplasm unclassifiable). Risk assessment according to the International Prognostic Scoring System was low-risk in 23%, intermediate-1 in 29%, intermediate-2 in 35%, and high-risk in 13%. Karyotype was abnormal in 68%, with chromosomes 7 (30%), 5 (26%), 8 (26%) and 3 (17%) being most frequently affected. No differences in the distribution of gender, World Health Organization subtype, acute myeloid leukemia progression, International Prognostic Scoring System score, and cytogenetic risk were observed between patients with therapy-related myeloid neoplasms following radioiodine or other treatment modalities. Of 17 patients who received induction chemotherapy, 71% were refractory to this treatment or died from treatment-related toxicity. The median overall survival in the entire group was 21.7 months (95%-CI 10.5–33 months) and did not differ significantly in comparison to the survival of patients with therapy-related myeloid neoplasms following other cytotoxic treatments. Patients with therapy-related acute myeloid leukemia had significantly inferior overall survival (12.4 versus 28.7 months, P=0.002).

Conclusions

Patients developing a therapy-related myeloid neoplasm after radioiodine treatment usually present with biological characteristics similar to those seen in patients with therapy-related myeloid neoplasms following other cytotoxic treatment modalities, associated with a low response rate to induction chemotherapy and poor prognosis.     

Platelet counts and haemorrhagic diathesis in patients with myelodysplastic syndromes

Objectives: Most patients with myelodysplastic syndromes (MDS) present with single or multiple lineage cytopenias in peripheral blood despite a hypercellular bone marrow. Thrombocytopenia, attributable to ineffective platelet production by dysfunctional megakaryocytes, has been estimated to occur in 40–65% of patients. However, there are hardly any studies on the clinical relevance of low platelet counts in MDS. Methods: We retrospectively analysed data from 2900 patients in the Duesseldorf MDS Registry who were diagnosed at our laboratory between 1982 and 2007. Results: At the time of diagnosis, 43% of the patients had a platelet count lower than 100 000/μL. Platelets were lower than 20 000/μL in 7% of the patients, especially in those with advanced stages of MDS, who showed a higher frequency of thrombocytopenia and platelet transfusion dependency. On multivariate analysis, platelet anisometry, hypocellularity of megakaryopoiesis, maturational defects of megakaryocytes and platelets <20 000/μL were independent variables showing a statistically significant correlation (P < 0.05) with clinical signs of bleeding. Platelets lower than 100 000/μL were associated with significantly shortened survival (P < 0.00005), because of an increased risk of progression to acute myeloid leukaemia (AML) (30% vs. 21%) (P < 0.02) and bleeding (16% vs. 8%) (P = 0.0005). Conclusions: Thrombocytopenia is a strong predictor of short survival, with or without haemorrhagic complications.     

Secondary myelodysplastic syndrome after fludarabine therapy of a low-grade non-Hodgkin's lymphoma

We diagnosed a probable fludarabine-induced secondary MDS approximately 18 months after treatment of a low grade non-Hodgkin's lymphoma. After diagnosis of a B-cell lymphoma composed of relatively small cells, fludarabine was administered between May and October, 1997, to a 64-year-old female patient. In December 1998, a mild bicytopenia was present with a leukocyte count of 3800/microl and platelets of 142000/microl. The white cell differential count was normal. The hemoglobin level was normal, but MCV was elevated. Bone marrow cytology revealed normal cellularity with dyserythropoiesis and dysmegakaryocytopoiesis. PAS staining showed scattered positivity in early erythroid cells. In 12 of 20 mitoses, the karyotype showed complex rearrangements, described as 46,XX,t(4;11)(q23?24;q13),del(5q),del(7)(q22),+mar[8]/45,-3. A diagnosis of treatment-related MDS was made. While there was no evidence of bone marrow infiltration by the lymphoma, CT scans demonstrated paraaortic lymph nodes up to 10 cm in diameter. After one course of CHOP chemotherapy, prolonged bone marrow aplasia and septic complications occurred. Chemotherapy was abandoned and Rituximab was administered. In July and November, 1999, bilateral pneumonia and urinary tract infection, respectively, were treated with antibiotics. NHL was in complete remission, but peripheral blood counts deteriorated markedly, and transfusions of packed red cells had to be started in November, 1999. The suspicion of leukemic transformation could not be confirmed because the patient declined further bone marrow biopsies. In December, 1999, the patient died from pneumonia.