Lung nodules: what they are, whether they are cancer and what happens next

A lung nodule (pulmonary nodule) is a small, round spot or shadow in the lung seen on a CT scan. North Bristol NHS Trust likens it to a "spot" or "blob". University Hospitals Southampton says nodules usually measure less than 1cm and occasionally up to 3cm.

Nodules do not usually cause any symptoms, so people are often unaware they have one. They are typically found incidentally, when a CT scan is done for another medical reason. You can have several nodules, which North Bristol says is not always more serious than having one.

The RM Partners cancer alliance describes lung nodules as a common incidental finding when a CT scan or chest X-ray covering the lungs is done.

Most pulmonary nodules are benign, meaning not cancer. University Hospitals Southampton says that occasionally nodules can indicate early-stage lung cancer, and that is why they are checked so treatment can start as soon as possible if needed. North Bristol says that in a very small number of people the nodule could be an early lung cancer.

It is not always easy to know the cause from one scan. North Bristol explains that benign nodules usually do not grow but cancerous ones eventually get bigger, which is why repeat scans over time are the best way to assess them.

University Hospitals Southampton lists inflammation, infection, scarring, a normal gland in the lung such as a lymph node, a hamartoma (a small lump containing fat, cartilage and connective tissue), and, less commonly, early lung cancer.

North Bristol adds that nodules may be caused by scarring from lung infections and are common in people who have had TB in the past. It says about 1 in 4 older people who smoke or have smoked have nodules, and about 1 in 10 people who have never smoked may have them.

University Hospitals Southampton explains that the CT scan is reviewed by a nodule multidisciplinary team (MDT) including a consultant radiologist and a respiratory consultant, who then write to you and your GP with the next steps. North Bristol says your CT result is usually sent to your hospital consultant within 4 weeks of the scan, who then contacts you by phone, letter or clinic appointment.

Nodules usually need monitoring over a period of 2 to 4 years, which is known as surveillance, according to British Thoracic Society guidelines. The follow-up CT scan is usually 3 or 12 months after the first scan, and North Bristol says scans are every 3, 9 or 12 months depending on the case.

If a nodule grows or changes, North Bristol says the consultant may arrange more tests, which could include a special scan called a PET scan or a biopsy. A biopsy takes a small piece of the nodule to be examined, and North Bristol notes it can be difficult or risky for very small nodules.

University Hospitals Southampton says the respiratory team will discuss your CT results with you, and whether you may benefit from further tests such as more specialist scans and a biopsy.

University Hospitals Southampton says pulmonary nodules and lung cancer are both more common in people who smoke, and that stopping smoking can help reduce this risk and improve general health. Free stop-smoking services are available through your GP or pharmacist.

Some nodules are found at a lung health check. The NHS says lung cancer screening is offered in some parts of England to people aged 55 to 74 who have ever smoked, and a CT scan may be offered if the check finds a higher risk of lung cancer; results arrive within 4 weeks.

It is very unlikely that chest symptoms are caused by a nodule, North Bristol says, but it is important to let your GP know if you develop any. University Hospitals Southampton advises contacting your GP immediately for new symptoms such as:

• A persistent cough.

• Coughing up blood.

• Unexplained weight loss.

• Breathlessness.

• Pain in the chest.

On the NHS nodules are managed through hospital respiratory and radiology services, often by a nodule MDT and a lung nurse navigator, with your GP kept informed. Follow-up scans are arranged for you.

Private CT scanning and respiratory consultations are available, but the same national guidance on surveillance intervals applies, so it helps to share previous scans so that comparisons can be made.