Platelets are disc-shaped elements in the blood that assist in blood clotting. During normal blood clotting, the platelets clump together (aggregate).

A normal platelet count in a healthy individual is between 150,000 and 450,000 per microlitre of blood.
Normal Platelet Count (PLT): 150-450 x 10⁹/L

In MDS, the bone marrow is usually more active than normal, yet the blood cells it produces are not healthy (we refer to that as ‘dysplastic’), they do not work as well as they should and many die either before they reach the bloodstream or shortly afterwards. This results in the number of blood cells in the bloodstream being reduced. This is referred to as a ‘cytopenia’.

About half of MDS patients will have a reduced platelet count at diagnosis, this is called thrombocytopenia.

Scanning electron micrograph of blood cells. From left to right: red cell, activated platelet, white cell. (Wikimedia Commons: Electron Microscopy Facility at The National Cancer Institute at Frederick (NCI-Frederick)

Whether the number of platelets is low or the platelets function poorly, it means that bruising and bleeding can sometimes be a serious problem in MDS.

If you have a low platelet count, it is usually advisable to avoid blood-thinning agents and non-steroidal anti-inflammatory drugs. However, this should be discussed with your doctor as there are exceptions where the benefit you will receive from these drugs outweighs the risks.

Platelets can be transfused but because they only last about four days, they are not routinely given even when the platelet count is very low. However, if you have an infection, are on blood thinners or have suffered from bleeding, you might benefit from platelet transfusions to keep your platelet count at a higher level. Your doctor or nurse will inform you when this is necessary.

Latest advances in treatment

In a recent scientific paper, "Thrombocytopenia and platelet transfusion in myelodysplastic syndromes", Kathleen Cheok, Prof. David Bowen and colleagues,  studied the clinical and haematological data from patients on the South Australian Myelodysplastic Syndrome Registry with respect to thrombocytopenia and its treatment. Full article in Transfusion (September 2020)

The authors observed that platelet transfusion continues to be the cornerstone of bleeding treatment for patients with severe thrombocytopenia, and to prevent bleeding in patients at high risk of bleeding complications.

They also summarise the alternative therapeutic options to platelet transfusion:

• Antifibrinolytics such as tranexamic acid, typically in patients with mucosal bleeding, either as treatment or prophylaxis.

• Thrombopoietin (a hormone that regulates platelet production) or its analogue Romiplostim, which has been proved to improve platelet counts and reduce bleeding episodes and platelet transfusions in lower-risk patients with MDS, with an acceptable medium-term safety profile. ^{(1) (2)}

• Androgens (male hormones) such as danazol, which have been reported to improve the production of blood cells and platelets, particularly thrombocytopenia, in MDS as in aplastic anaemia.^{(3) (4) (5)}. Since its efficacy varies among studies, androgens are not widely used.

• Disease-modifying therapies, such as hypomethylating agents, chemotherapy, or bone marrow transplant, which seek to raise platelet count by inducing remission of MDS.

In terms of future developments, the authors suggest the ideal approach to treat severe thrombocytopenia in MDS would be to use a safe and effective drug to raise platelet counts to levels not associated with haemorrhage.
They add: "It is likely that evidence on supporting thrombocytopenic patients with MDS will accumulate from retrospective studies, prospective registry data, and the best that we can do in designing less than-perfect trials".

References

1. Giagounidis A, Mufti GJ, Fenaux P, et al. Results of a randomized, double-blind study of romiplostim versus placebo in patients with low/intermediate-1-risk myelodysplastic syndrome and thrombocytopenia. Cancer. 2014;120(12):1838–1846.
2. Kantarjian HM, Fenaux P, Sekeres MA, et al. Long-term followup for up to 5 years on the risk of leukaemic progression in thrombocytopenic patients with lower-risk myelodysplastic syndromes treated with romiplostim or placebo in a randomised double-blind trial. Lancet Haematol. 2018;5(3):e117–e126.
3. Chabannon C, Molina L, Pegourie Bandelier B, Bost M, Leger J. Hollard D. a review of 76 patients with myelodysplastic syndromes treated with danazol [see comments]. Cancer. 1994; 73(12):3073–3080.
4. Chan G, DiVenuti G, Miller K. Danazol for the treatment of thrombocytopenia in patients with myelodysplastic syndrome. Am J Hematol. 2002;71(3):166–171.
5. Stadtmauer EA, Cassileth PA, Edelstein M, et al. Danazol treatment of myelodysplastic syndromes. Br J Haematol. 1991;77: 502–508.