Monosomal Karyotype in MDS and Secondary AML: Do Autosomal Monosomies Have the Same Poor Prognostic Impact As Monosomy 5 and 7?

A monosomal karytype (MK) is defined by the presence of at least two or more distinct autosomal monosomies or an autosomal monosomy along with a structural defect. In AML this cytogenetic pattern has a very well-known poor prognostic significance independently of the specific chromosome involved. Currently, in MDS this negative prognostic influence is also emerging as recent data suggest that any monosomy in a complex karyotype (≥3 abnormalities) may have the same poor prognostic impact as monosomy 5 and 7 (−5,−7).

Thus, the principal goal of the present study was to test whether a MK further worsen the already poor prognostic influence of a complex karyotype and to establish whether autosomal monosomies have the same unfavourable prognostic impact on OS and progression free interval (PFI) as −5/−7.

The eighty-five consecutive MDS patients with a complex karyotype analysed by the present study were included in a series of 631 patients who came at our observation in the period January 2000-December 2010. They were thirty-two females and fifty-three males with a median age of 65 years (range 25–85). Fifty-five patients were diagnosed as MDS and were subdivided in 3 RARS, 6 RA, 6 RCMD, 2 RCMDS, one MDS-u, 13 RAEB-1 and 24 RAEB-2. The IPSS score was intermediate-1 in 5, intermediate-2 in 23 and high in 27. During the follow-up 31 MDS patients died and 41 experienced disease progression (3 RARS, 5 RA, 4 RCMD, one MDS-u, 9 RAEB-1 and 19 RAEB-2). Thirty patients were diagnosed as AML evolved from MDS. Fifteen of them received supportive treatment only, the remaining single agent chemotherapy to control leukocytosis. Nineteen of these thirty patients died of disease related complications.

On conventional cytogenetics 37 patients (4 RA, 5 RCMD, one MDS-u, 8 RAEB-1, 12 RAEB-2 and 7 AML) presented a complex karyotype without monosomies and 48 (3 RARS, 2 RA, 2 RCMDS, one RCMD, 5 RAEB-1, 12 RAEB-2, 24 AML) a complex karyotype with monosomies. These two patients subgroups were comparable in terms of age, sex distribution, haemoglobin level, leukocyte or platelet counts, bone marrow blast cell percentage and IPSS score. However, median survival was 8 months (range 1–131) for patients with a complex karyotype without monosomies and 5 months (range 1–81) for those with a complex karyotype with monosomies (p=0.001). Twenty patients (54.0%) without monosomies died after a median time of 6 months (range 2–35), whereas 30 patients (62.5%) with monosomies died after a median time of 5 months (range 1–24). Disease progression was observed in 22 (59.4%) and 19 (39.5%) patients respectively (p=0.001). The 48 patients with a MK were further subdivided in those with −5/−7 versus those with other autosomal monosomies. The 23 patients with −5/−7 presented a median survival of 4 months (range 1–15) and the 25 with other monosomies presented a median survival of 5 months (range 1–81) (p=Not Significant). Fourteen −5/−7 patients died after a median time of 4 months (range 1–15) and 13 patients with autosomal monosomies died after a median time of 6 months (range 1–24). Disease progression occurred in 12 (52.1%) and 7 (28%) respectively.

i) a MK further refines the prognostic stratification of MDS with a complex karyotype as it identifies a subgroup of patients with an extremely poor clinical outcome; ii) autosomal monosomies have an impact on disease outcome as detrimental as −5/−7.

No relevant conflicts of interest to declare.