Cancer-related Anaemia: Causes, Symptoms and Treatment

What Is Cancer-related Anaemia?

Cancer-related anaemia (also called tumour-associated anaemia) is a form of anaemia that commonly occurs in patients with cancer. It is defined as a reduction in haemoglobin concentration below the normal range (below 12 g/dl in women and below 13 g/dl in men). It is one of the most frequent complications of cancer and significantly impairs the quality of life of affected individuals.

Causes

Cancer-related anaemia is usually caused by several factors acting simultaneously:

• Chronic inflammation: Tumours trigger persistent inflammatory responses in the body. Inflammatory signalling molecules (cytokines) suppress red blood cell production in the bone marrow and disrupt iron metabolism.
• Iron deficiency: Chronic bleeding, for example in colorectal or gastric cancer, as well as reduced food intake, can lead to iron deficiency that impairs blood cell formation.
• Chemotherapy: Many cytostatic drugs damage the blood-forming cells in the bone marrow, reducing the production of red blood cells.
• Radiation therapy: When large areas of bone marrow tissue are irradiated, blood cell production may be permanently impaired.
• Direct bone marrow involvement: Certain tumour types, such as leukaemia or bone metastases, directly displace the blood-forming tissue.
• Erythropoietin deficiency: If the tumour affects the kidneys, production of the blood-stimulating hormone erythropoietin may decrease.
• Haemolysis: In some cases, red blood cells are prematurely broken down due to tumour-related mechanisms.

Symptoms

The symptoms of cancer-related anaemia are similar to those of other forms of anaemia, but may be intensified by the underlying disease:

• Persistent fatigue and exhaustion (cancer-related fatigue)
• Pale skin and mucous membranes
• Shortness of breath, particularly during physical exertion
• Rapid or irregular heartbeat
• Dizziness and difficulty concentrating
• Headaches
• Reduced physical and mental performance

Cancer-related fatigue is a central symptom and differs from ordinary tiredness in that it is not relieved by sleep or rest.

Diagnosis

Cancer-related anaemia is primarily diagnosed through blood laboratory tests:

• Full blood count: Measurement of haemoglobin, haematocrit, red blood cell count, and erythrocyte indices (MCV, MCH, MCHC).
• Iron status: Assessment of serum iron, ferritin, transferrin, and transferrin saturation to distinguish between absolute and functional iron deficiency.
• Reticulocyte count: Provides information about the activity of blood cell production in the bone marrow.
• Inflammatory markers: CRP and interleukin-6 may indicate inflammation-related anaemia.
• Bone marrow biopsy: In unclear cases or suspected bone marrow involvement, a tissue sample from the bone marrow may be necessary.

Treatment

Treatment of cancer-related anaemia depends on the underlying cause, the severity of the anaemia, and the general condition of the patient:

Erythropoiesis-stimulating Agents (ESAs)

Erythropoietin or its analogues (e.g., darbepoetin alfa) are used to stimulate the production of red blood cells in the bone marrow. They are primarily used for chemotherapy-induced anaemia. Their use requires careful indication assessment, as ESAs can increase the risk of thrombosis.

Iron Supplementation

When iron deficiency or functional iron deficiency is confirmed, iron is administered either orally or intravenously. Intravenous administration is often more effective in cancer patients, as intestinal absorption is frequently impaired.

Blood Transfusions

In cases of severe anaemia with acute symptoms or haemoglobin levels below 7-8 g/dl, red blood cell concentrates may be transfused. Transfusions act quickly but carry risks such as transfusion reactions and possible immune modulation.

Treatment of the Underlying Disease

The most effective measure for managing cancer-related anaemia is successful treatment of the underlying tumour. As the tumour regresses, blood cell production often normalises.

Supportive Measures

In addition, a balanced diet, physical activity within the limits of individual capacity, and psychological support can help alleviate the fatigue associated with anaemia.

Relevance to Cancer Therapy

Untreated cancer-related anaemia can reduce the effectiveness of cancer treatment, as oxygen-deficient tumour tissue (hypoxia) is more resistant to radiotherapy and chemotherapy. Furthermore, anaemia is associated with a worse prognosis and reduced quality of life. Early recognition and treatment of cancer-related anaemia is therefore an important component of oncological supportive care.

References

1. Ludwig H. et al. - The European Cancer Anaemia Survey (ECAS): A large, multinational, prospective survey defining the prevalence, incidence, and treatment of anaemia in cancer patients. European Journal of Cancer, 2004.
2. Aapro M. et al. - Management of anaemia and iron deficiency in patients with cancer: ESMO Clinical Practice Guidelines. Annals of Oncology, 2018.
3. National Comprehensive Cancer Network (NCCN) - Clinical Practice Guidelines in Oncology: Cancer- and Chemotherapy-induced Anemia, 2023.