Why screening matters

Lung cancer often causes no symptoms until it is advanced. Low dose CT scanning of high risk individuals, mainly long term smokers, has been shown to find cancers early, when cure is possible, and to save lives. Screening programmes are expanding in many countries.

Who it is for

There is currently no lung cancer screening programme in Singapore. Trials of low-dose CT in high-risk individuals have picked up early lung cancers, leading to early treatment and better survival, but there are many obstacles to large-scale population screening: cost, potential overdiagnosis and unnecessary procedures. Lung cancer screening should therefore be offered only when a patient has adequately understood its pros and cons.

In general, most trials have included people over 50 with a significant smoking history, roughly 20 cigarettes a day for 20 years. With the rising number of lung cancers in people who have never smoked, these criteria may change in future.

People who have never smoked

We also know that lung cancer occurs in people who have never smoked, particularly in Asia, and who should be screened is a question that is still being studied. The number of lung cancers in non-smokers is rising, especially among Asians. The exact cause remains unclear, but diagnosis and treatment have improved at a similar pace, and some lung cancers diagnosed at a later stage can have very good outcomes with targeted treatments.

What a low-dose CT involves

A low-dose CT is a simple CT scan done without intravenous contrast, using 80 to 90% less radiation than a conventional CT scan. It takes about 10 to 20 minutes and needs very little preparation. These scans can pick up nodules as small as 1 to 2 mm, and follow-up of such nodules is highly individualised, ranging from careful surveillance to biopsy for further evaluation.

The downsides

Screening comes with its own downsides, including nodules that turn out to be harmless and need follow up. The main downside is finding nodules that are harmless or due to simple infections. In a small number of patients this leads to unnecessary scans and procedures, which can cause anxiety and carry the potential complications of a biopsy. These issues must be adequately discussed before any form of lung cancer screening is offered. It is a conversation worth having with your doctor, and it is never a substitute for stopping smoking.

Lung and Respiratory Conditions: A Patient Guide · Lung Nodules: What to Do Now? · The Aeden Physicians

Frequently Asked Questions

Who should have lung cancer screening?

Most trials have included people over 50 with a significant smoking history, roughly 20 cigarettes a day for 20 years. There is currently no screening programme in Singapore, so screening is offered individually, once the pros and cons have been adequately understood.

What are the downsides of lung cancer screening?

Screening can find nodules that turn out to be harmless or due to infection, leading in a small number of patients to unnecessary scans and procedures, anxiety and the potential complications of a biopsy. It is never a substitute for stopping smoking.