Myelosuppression is one of the most common dose‐limiting side‐effects of chemotherapy (Schulmeister [224]). All chemotherapy has an effect on the bone marrow, resulting in a reduction in white blood cells, red blood cells and platelets. Myelosuppression that causes bleeding or infection can be life‐threatening. Colony‐stimulating factors (CSFs) enhance granulocyte production and shorten the nadir (the point at which the lowest blood count is reached after chemotherapy) (Schulmeister [224]).

Leucopenia is classified as a lower than normal number of white blood cells in the bloodstream. White blood cells are often categorized as granulocytes and agranulocytes. Granulocytes include neutrophils, which have a lifespan of 6 hours to a few days; eosinophils, which have a lifespan of 8–12 days; and basophils, which have a lifespan of a few hours to few days. CSFs such as filgrastim and pegfilgrastim can be used to manage neutropenia, a condition in which the number of neutrophils in the bloodstream is decreased, impairing the body's ability to fight infection (Campbell [24]).

The lifespan of a red blood cell is 120 days. A patient is considered anaemic if the haemoglobin level is lower than 8 g/dL (Weinstein and Hagle [265]). Patients with anaemia may be asymptomatic or may manifest symptoms such as headache, light‐headedness, shortness of breath, fatigue or pallor of skin and nail beds. A blood transfusion will help raise the haemoglobin level. One unit of red blood cells can raise the haemoglobin by 1 g/dL (Schulmeister [224]). Erythropoietin can be used to stimulate red blood cell production (Weinstein and Hagle [265]).

Thrombocytopenia is classified as a lower than normal number of platelets in the bloodstream. A normal range for the platelet count is 150–400 × 10⁹/L. The risk of bleeding increases if the platelet count reduces to 100 × 10⁹/L (Schulmeister [224]). Signs and symptoms of thrombocytopenia include bruising, petechiae, bleeding from the gums and nose, and haemorrhage in the central nervous system or gastrointestinal tract (Dougherty and Bailey [61]). Risk of bleeding is considered severe when the platelet count reaches 20 × 10⁹/L. Activities that carry a high risk, such as contact sports, should be avoided since they can cause injury and subsequent bleeding. Patients should be encouraged to report signs of spontaneous bruising, nosebleeds, bleeding gums and bloody stools (Weinstein and Hagle [265]). A low platelet count can delay the continuation of chemotherapy. Platelet transfusions can be given in order to manage thrombocytopenia.