Key points
- Smoking is a major cause of lung cancer.
- People living with HIV have a higher risk of lung cancer than people without HIV.
- Many people do not have symptoms during the early stages of lung cancer.
Cancer occurs when some of the body’s cells begin to divide without stopping and spread into surrounding tissues. Cancer cells can spread to other parts of the body. For example, cancer cells in the lung can travel to the bones and grow there. This is known as metastasis.
Lung cancer is one of the most common cancers and a leading cause of cancer death in the UK and worldwide. Smoking is the biggest risk factor for lung cancer, but people who have never smoked can still get lung cancer. Studies show that lung cancer occurs more often among people living with HIV compared to people without HIV.
Many people don’t have any symptoms during the early stages of lung cancer. That’s why it’s often diagnosed late. You have the best chance of a good outcome if your cancer is diagnosed and treated as soon as possible, without delay.
Researchers are working on developing more treatments for lung cancer. Currently it’s one of the cancers that is most difficult to treat.
Your lifestyle and lung cancer
Some lifestyle changes can reduce your risk of developing lung cancer.
Don’t smoke. Smoking is the leading cause of lung cancer. It also raises the risk of mouth, throat, bowel and other types of cancer. Stopping smoking lowers the risk of developing cancer. Experts estimate that ten years after quitting, the risk of lung cancer is cut in half.
Take HIV treatment and keep your viral load undetectable. Studies show that people who start HIV treatment promptly have a lower risk of cancer.
Who is at risk?
People who currently smoke tobacco (cigarettes, roll-ups, cigars or pipes) and former smokers are most likely to develop lung cancer. This is especially true for heavy smokers, but even light or occasional smoking – and exposure to second-hand smoke – raises the risk. E-cigarettes don’t contain tobacco and many of the toxic chemicals found in cigarettes, so are less harmful. But we still don’t know enough about their long-term effects.
Radon (an invisible gas sometimes found in buildings), asbestos, air pollution and exposure to radiation can also increase the risk for lung cancer.
Lung cancer mainly affects older people, especially those aged 65 or over. In recent decades, rates of lung cancer have decreased for men and increased for women. Lung cancer appears to be rising particularly among women who never smoked compared to men who never smoked. Experts are unsure why.
Your risk of lung cancer can also be affected by your genes. If a close family member, for example your parent or sibling had lung cancer, your risk of lung cancer may be higher.
Lung cancer in people with HIV
People living with HIV have a higher risk of developing lung cancer and several other cancers compared to people without HIV. Lung cancer is one of the most common non-AIDS cancers and it’s the cancer causing most death among people living with HIV.
One potential reason for this increased risk is that people with HIV are more likely to smoke than the general population. But the risk for lung cancer is also increased for people with HIV who don’t smoke.
People with HIV are also now living longer than ever, because of effective HIV treatment. This means they’re more likely to develop conditions typical for older age, like lung cancer. However, people with HIV also get cancer at younger ages. The reason for this is unclear.
Weaker immune function may contribute to higher cancer risk. Immune cells like CD8 and CD4 play an important role in locating and destroying cancer cells. Research has shown that people living with HIV with a low CD4/CD8 ratio have a higher risk of developing any type of cancer in future.
Having increased inflammation and chronic lung problems, like chronic obstructive pulmonary disease (COPD), may also increase the risk of getting cancer.
HIV treatment itself does not cause lung cancer.
Symptoms
Early-stage lung cancer often does not cause symptoms. That makes it difficult to detect. As the disease progresses, symptoms could include:
- a cough that doesn’t go away
- coughing up blood
- shortness of breath
- chest pain
- wheezing
- hoarseness
- fatigue or weakness
- unexplained weight loss
- unexplained pain
- recurring lung infections such as pneumonia.
Other less serious conditions can cause similar symptoms. It's a good idea to see your doctor if you’re worried or your symptoms persist or worsen.
Diagnosis and monitoring
The later lung cancer is detected, the more difficult it is to treat. That’s why screening for lung cancer is important. Studies show that lung cancer screening for people aged 55 and older who are current or former heavy smokers reduces lung cancer deaths. But currently most lung cancer cases are detected at an advanced stage.
In 2022, the National Screening Committee in the UK recommended that people should be invited to screening if they’re at high risk for lung cancer. Since then, the NHS in England has started lung cancer screening for everyone aged between 55 and 74 who either smokes or used to smoke. There are plans to make screening programmes more widely available in the rest of the UK as well.
If you experience any symptoms, a chest X-ray, CT scan or MRI (magnetic resonance imaging) scan may be done to look for abnormal areas in the lungs. If a suspected mass or tumour is found, your doctor may take a biopsy (a small piece of tissue to examine under a microscope). Your doctor may also look for abnormal cells in your sputum (phlegm), or mucous coughed up from the lungs.
The two main types of lung cancer are small cell and non-small cell. Non-small-cell lung cancer is by far the most common (about 85% of cases). Non-small-cell lung cancer is further divided into adenocarcinoma, squamous cell cancer and large cell carcinoma. Tumours may be tested for genetic mutations (including ALK, EGFR, KRAS and others) to help guide decisions about treatment.
Studies suggest that people with HIV have similar types of lung cancer, stage at diagnosis and presence of genetic mutations as people without HIV.
Treatment and management
Treatment for lung cancer has improved in recent years, but it’s still one of the cancers that's most difficult to treat. The type of treatment you may receive depends on how advanced the cancer is, how many tumours there are and whether it has spread to other parts of the body. Most people receive a combination of treatments, for example surgery and chemotherapy.
Surgery: If lung cancer is caught early, it may be possible to remove all or most of it with surgery. This is usually not possible if the cancer has spread (metastasised).
Radiotherapy: Radiation may be used to destroy cancer cells. Usually it’s given with a large machine that aims beams of radiation at the affected part of the lung. Radiation can sometimes shrink tumours that cannot be removed, which can help relieve pain and other symptoms.
Chemotherapy: Traditional chemotherapy drugs stop cells from dividing which stops them from growing and spreading. Many chemotherapy drugs are given through a drip into a vein.
Targeted therapy: Targeted or precision medications are designed to attack cancer with specific characteristics, for example certain gene mutations. There are many different types of targeted therapy, including gene therapy and monoclonal antibodies. Targeted therapies may be small molecules taken as pills or monoclonal antibodies given through an intravenous (IV) drip.
Immunotherapy: Immune-based medications help the immune system identify and attack cancer cells. Some tumours can turn off immune responses against them, and drugs known as checkpoint inhibitors release the brakes and restore T cell activity. Some checkpoint inhibitors, alone or in combination with chemotherapy, have shown good results in people with lung cancer. But they don't work for everyone and it is difficult to predict who will benefit.
Like any other treatment, cancer treatments can have side effects which can sometimes be unpleasant. Each treatment has different side effects and it’s important to ask about the potential side effects of the specific treatment that is suggested for you. For example, not all chemotherapy drugs make your hair fall out. You may be given additional medications to counteract side effects.
The same types of treatment are used for people with HIV and people without HIV. The treatment you are offered shouldn’t be different to that of other people just because you have HIV.
Most clinical trials of newer targeted therapies and immunotherapies did not include people with HIV, so doctors have less experience using these medications in people with HIV. The British HIV Association says unless there's a reason to suspect they will have harmful effects, people living with HIV should not be denied these effective new treatments.
It’s recommend that you continue to take HIV treatment during your cancer treatment or, if you haven’t already, that you start. Taking HIV treatment during cancer treatment is associated with living longer and a lower risk of opportunistic infections. Chemotherapy and radiotherapy both suppress the immune system, which may result in a significant drop in your CD4 count. You should be given drugs to prevent opportunistic infections (this is known as prophylaxis). Your CD4 count may be checked more often after cancer treatment than it would be normally.
There can be drug-drug interactions between cancer treatments and HIV treatments. For this reason, it may be necessary to make some adjustments to your HIV treatment or your cancer treatment.
As treatments for HIV and cancer can both cause side effects, your doctors should keep an eye on how they are affecting you. In some cases (such as nausea from chemotherapy), highly effective treatments to limit side effects are now available. If side effects become too severe, your doctors may need to adjust one of the treatments.
Because of these issues, it's very important that the doctors treating your cancer and your HIV work together. There should also be contact between the pharmacists in the cancer and HIV clinics.
A multi-disciplinary team will make recommendations about your treatment. This team may include an oncologist (a doctor who specialises in treating cancer), a radiologist (a doctor who interprets the results of scans or provides radiotherapy) and a pathologist (a doctor who examines tissue for cancer cells). You will be supported by a cancer specialist nurse during your cancer journey. If a cure is not possible, palliative care can relieve pain and other symptoms and help you maintain the best possible quality of life.
Other sources of information
For more information, you may find the website of Macmillan Cancer Support helpful: www.macmillan.org.uk. You can also contact their helpline team on 0808 808 0000.
For more information on cancer organisations around the world, you may find useful links on the International Cancer Information Service Group website or on the Cancer.net website.
This project has been made possible with grant support from MSD. MSD has no editorial control or input into this project.