Lung cancer: screening, diagnosis, and investigation - clinical fact sheet and MCQ

Overview

Lung cancer remains the leading cause of cancer-related mortality in Australia. Early detection significantly improves outcomes. Despite advancements in therapy, prognosis is strongly linked to stage at diagnosis - 5-year survival is 68% for stage 1 disease, but just 3% at stage 4. However, symptoms are often non-specific, which can delay recognition and referral. Primary care clinicians are critical in initiating timely investigation and referral, especially given that many patients have multiple GP consultations prior to diagnosis. 

In July 2025, the new National lung cancer screening program commences, including new Medicare items and reporting requirements.

Lung cancer diagnosis in primary practice

Timely and accurate diagnosis of lung cancer involves recognising risk factors, interpreting symptoms appropriately, selecting optimal imaging, and knowing when to refer.

1. Risk factors for lung cancer

Key risk factors include:

• current or past tobacco smoking (primary risk factor)

• however, note up to 10% of males and 35% of females diagnosed with lung cancer have never smoked

• environmental/occupational exposures

• passive smoking

• occupational exposures, eg asbestos, radon, diesel exhaust, silica

• air pollution

• increasing age

• chronic lung diseases (eg COPD, pulmonary fibrosis)

• personal history of cancers such as lung, head and neck, or bladder cancer

• family history of lung cancer,

• sociodemographic factors

• Aboriginal and Torres Strait Islander people have twice the incidence and double the risk of mortality from lung cancer

Lung cancer incidence and mortality rise with increasing remoteness and socioeconomic disadvantage.

2. Symptoms, signs, and red flags

Common symptoms can mimic other conditions such as COPD or heart failure. Persistent or unexplained symptoms lasting more than 3 weeks - or sooner in high-risk patients - should prompt further investigation. 

Symptoms might include:

• new or altered cough

• chest or shoulder pain

• dyspnoea

• hoarseness

• weight loss or loss of appetite

• persistent or recurrent chest infection

• fatigue

• haemoptysis (including bright red, streaked, or rust-coloured sputum)

Signs:

• finger clubbing

• cervical/supraclavicular lymphadenopathy

• superior vena cava obstruction signs (oedema of face, neck, upper torso and upper limbs, distended neck veins,  positive Pemberton’s sign)

• abnormal chest signs, eg stridor, wheeze, crepitations, decreased/absent breath sounds

• pleural effusion

• deep vein thrombosis

• features suggestive of metastasis (brain, bone, liver, skin)

• thrombocytosis

An interactive diagnostic tool for investigating symptoms of lung cancer is available from Cancer Australia here.

3. Differential diagnoses

Consider and exclude other conditions presenting with similar symptoms:

• COPD exacerbations

• chronic heart failure

• coronary artery disease

• tuberculosis

• bronchiectasis

• pneumonia (particularly when recurrent or unresolved)

4. Initial assessments and imaging

• Urgent chest X-ray is the first-line investigation for symptomatic patients unless the clinical picture necessitates an urgent chest CT (see below) 

• ensure patients receive results within one week

• be aware of chest X-ray false negatives (up to 25%)

• Arrange an urgent chest CT (with contrast preferred for improved sensitivity and specificity of diagnosis and accurate staging, unless contraindicated) if:

• chest X-ray suggests lung cancer

• high clinical suspicion of lung cancer (even if  normal X-ray findings)

• persistent or unexplained haemoptysis

• signs of superior vena cava obstruction

5. Referral

Referral (within 2 weeks) is recommended when:

• chest X-ray or CT suggests malignancy

• high clinical suspicion exists despite normal imaging

• there are signs of metastatic spread or red flag symptoms

All referrals should be directed to a respiratory physician or other specialist linked with MDTs experienced in managing lung cancer. For MDT listings, consult the Lung Foundation Australia MDT directory.

Urgent referral to emergency care is warranted for:

• massive haemoptysis

• stridor

• respiratory compromise

New National lung cancer screening program

The new National lung cancer screening program (NLCSP) will utilise low-dose CT (LDCT) without contrast as it has greater sensitivity than X-ray. Screening with LDCT has proven to be effective with relative risk reductions in lung cancer-specific mortality of 20% and 24% reported in the NLST and NELSON trials, respectively.  

Eligibility criteria:

• age between 50-70 years

• asymptomatic

• current smoker or quit smoking in the last 10 years

• history of tobacco cigarette smoking of ≥30 pack years

GPs will play a crucial role in identifying patients that are eligible and suitable for screening, requesting the LDCT scan, communicating results, and referring patients for ongoing management when required. Table 1 below further details the roles and responsibilities of requesting practitioners in the screening and assessment pathway.

Table 1: roles and responsibilities of referring practitioners from the National lung cancer screening program guidelines, pg 14.

Two new MBS items for the screening program will cover:

• screening LDCT performed approximately every 2 years

• interval LDCT: a shorter interval follow-up scan (in 1-3, 6 or 12 months) to monitor for nodule growth or other changes

It is mandatory for these items to be bulk-billed by the radiology provider. 

Reports for the person’s initial NLCSP scan and any subsequent scans will be read and reported using the NLCSP nodule management protocol. 

More information is available on the MBS website.

Nodule management protocol as per the National lung cancer screening program is summarised below in table 2. This protocol uses a risk-based approach to guide follow-up timing for lung nodules and other findings detected in screening. Follow-up intervals range from 1–3 months for potentially infectious or moderate-risk nodules, to 12–24 months for stable or low-risk findings.

Baseline and follow-up categories may be found here.

Table 2: simplified nodule management protocol flowchart from the National Lung Cancer Screening Program nodule management protocol, pg 8.

Referral and further investigation

• Participants of the screening program categorised as high risk or very high risk on screening, should be urgently referred to a respiratory physician or specialist affiliated with a lung cancer multidisciplinary team (MDT) for further investigation and management

References

Cancer Australia. Investigating Symptoms of Lung Cancer. 2020. (last accessed May 2025).

Australian Government Department of Health, Disability and Ageing. How the National Lung Cancer Screening Program will work. 2025. (last accessed June 2025). 

Australian Government. National Lung Cancer Screening Program - Nodule Management Protocol. 2025. (last accessed June 2025).

Australian Government. National Lung Cancer Screening Program Program Guidelines. 2025. (last accessed June 2025).

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