Can Lung Cancer Cause Anaemia?

Anaemia is less often considered. But it does occur, and often more frequently than expected.

Anaemia can develop in people with lung cancer both before and during treatment. In some cases, it may even be one of the earlier signs that something is not quite right. Understanding how this happens helps explain some of the symptoms patients experience and why blood tests are a routine part of assessment.

What Is Anaemia and Why Does It Matter?

Anaemia occurs when there is a reduction in red blood cells or haemoglobin, the protein responsible for carrying oxygen around the body.

When haemoglobin levels fall, oxygen delivery becomes less efficient. This can lead to symptoms such as fatigue, breathlessness, dizziness, and reduced physical stamina.

These symptoms can be subtle at first. In some cases, they overlap with the effects of lung cancer itself, which can make them harder to recognise without investigation.

In practice, identifying anaemia helps build a clearer picture of a patient’s overall condition. It can influence how symptoms are interpreted and, in some cases, how treatment is approached.

When considered alongside imaging and biopsy results, it is part of the broader assessment that informs the development of a lung cancer treatment plan, where both the tumour and the patient’s overall health are considered together.

In practice, this is where careful interpretation becomes important. As a lung cancer specialist in London, bringing these findings together helps determine the most appropriate treatment approach.

How Lung Cancer Can Lead to Anaemia

There is no single explanation for anaemia in lung cancer. I mean, it is usually the result of several overlapping factors rather than one clear cause.

One of the most common mechanisms is anaemia of chronic disease. Cancer can create a persistent inflammatory response in the body. This affects how iron is processed and reduces the production of red blood cells in the bone marrow.

In more advanced cases, lung cancer may also affect the bone marrow directly. This can interfere with the body’s ability to produce healthy blood cells.

Blood loss is another possible contributor. Some patients experience haemoptysis, or coughing up blood. Even small amounts of repeated blood loss over time can lead to iron deficiency.

Nutritional factors may also play a role. Reduced appetite, weight loss, and general illness can lead to lower levels of iron, vitamin B12, or folate, all of which are required for red blood cell production.

In most cases, these factors overlap. Anaemia is therefore often multifactorial rather than due to a single cause.

The Role of Cancer Type and Stage

The likelihood of anaemia can vary depending on the type and stage of lung cancer.

Non-small cell lung cancer accounts for around 80 to 85 percent of cases and often develops more gradually. Anaemia may still occur, particularly as the disease progresses or if inflammation becomes more pronounced.

Small cell lung cancer tends to behave more aggressively. It is more likely to be associated with widespread disease at diagnosis. In some cases, this may include involvement of the bone marrow, which can directly affect blood cell production.

Anaemia is generally more common in advanced stages of lung cancer. Some studies suggest that it may be present in over 30 percent of patients at diagnosis.

This reflects the broader impact of the disease on the body as it progresses.

Can Treatment for Lung Cancer Cause Anaemia?

Treatment itself can also contribute to anaemia.

This is something that becomes more noticeable as treatment progresses, particularly with certain chemotherapy regimens.

Chemotherapy can suppress the bone marrow, reducing the production of red blood cells over time. This effect is more likely with certain drug combinations and may develop gradually during treatment.

Radiotherapy may have a similar impact in some situations, particularly if larger areas of the body are involved.

There are also indirect effects. Treatment can affect appetite and nutritional intake, which may lead to deficiencies in iron, vitamin B12, or folate. These deficiencies can contribute further to anaemia.

So while anaemia may be present at diagnosis, it can also develop or worsen during treatment.

Recognising the Symptoms

Anaemia often develops gradually, which means the symptoms can be subtle.

Patients may notice:

• Increasing fatigue or reduced energy
• Reduced stamina during normal activities
• Breathlessness with less exertion than usual
• Dizziness or lightheadedness
• Palpitations or a faster heartbeat
• Difficulty concentrating

These symptoms are not specific to anaemia and can overlap with the effects of lung cancer itself.

Blood tests are therefore an important part of the assessment. They provide a clear picture of haemoglobin levels and help determine whether anaemia is contributing to how a patient feels.

Why It Is Important to Identify and Manage Anaemia

Anaemia can have a meaningful impact on quality of life.

Lower haemoglobin levels can contribute to fatigue and reduced physical function. In some cases, it may also affect how well treatment is tolerated.

Management depends on the underlying cause. This may involve correcting nutritional deficiencies, adjusting treatment, or using supportive therapies such as blood transfusions where appropriate.

The key point is that anaemia is part of the overall clinical picture. It needs to be considered alongside the cancer itself when planning treatment.

About Dr James Wilson

Dr James Wilson is a consultant clinical oncologist specialising in lung cancer and thoracic cancers. Based in a full-time private practice in Central London, he focuses on guiding patients through diagnosis, staging, and treatment planning so that each decision reflects both the biology of the tumour and the overall condition of the patient.