There is so much we don’t know in medicine that could make a difference,
and often we focus on the big things, and the little things get forgotten. To
highlight some smaller but important issues, we’ve put together a series of
pearls that the Red Whale found at the bottom of the ocean of knowledge!
Lung cancer
In April 2011 NICE produced guidance on the diagnosis and treatment of lung cancer. A large part of this was dedicated to hospital
investigation and treatment. Here I will focus on the aspects around diagnosis related to primary care. First though, a new trial on
screening for lung cancer and a reminder of how reassuring a negative chest X-ray should (or shouldn’t!) be!
Screening for lung cancer
A number of different methods have been proposed for screening for lung cancer, from CXR to ordinary CT to low-dose CT scanning
(about the same radiation exposure as a mammogram).
The US National Lung Cancer Screening Trial (NLST) randomised 53,000 people at high risk of lung cancer to annual low-dose CT
or annual chest X-ray for 3y. High-risk individuals were defined as being aged between 55 and 74y with a greater than 30 pack year
smoking history and who were current or ex-smokers having given up within the last 15y.
For every 320 people screened by low-dose CT annually for 3y, 1 lung cancer death would be prevented. This compares
favourably with mammography!
BUT, the associated editorial cautioned about immediate implementation because 7 million individuals in the USA would meet the
entry criteria and the costs of implementation would be high (NEJM 2011;365:455)!
Subsequently, researchers have suggested that to reduce false positives the cut-offs for defining ‘abnormal’ could be changed,
although this needs prospective testing because it might also impact on benefits (Ann Int Med 2013;158:246).
A further trial has shown that low-dose CT scanning prevented very few deaths in low-risk populations so should be
restricted to those at highest risk (NJEM 2013;369:245).
The Americans are currently working up a screening programme (program!).
A UK RCT of lung cancer screening is underway and I doubt anything will happen here until this is finished.
‘But the CXR was normal…’
Most of us are probably reasonably reassured if a patient has a normal CXR. However, this paper in the BJGP a few years ago
should rather shake our confidence in the negative CXR. The paper was a retrospective cohort study of 164 people diagnosed with
lung cancer who had had a CXR in primary care. Looking at X-rays taken in the 3m before diagnosis (BJGP 2006;56:570):
90.5% of the CXRs were reported as abnormal with suspicions of malignancy.
3.5% were reported as abnormal but with no suspicion of malignancy.
6% were reported as completely normal.
No particular symptom or constellation of symptoms was more likely with a negative CXR.
For those whose CXR was older (taken in the last year), 23% of cancers were missed (10% were reported as completely normal,
13% were reported as abnormal but no suspicions of malignancy).
Beware the negative CXR!
NICE guidance on the diagnosis of lung cancer
NICE on lung cancer NICE CG 121, 2011
Suspicious clinical features: do an urgent CXR
Any of the following, lasting more than 3w OR unexplained by another illness:
Cough
Dyspnoea
Chest signs
Haemoptysis (at any time, does not have to have been present for 3w, unlike other symptoms)
Hoarseness
Chest/shoulder pain
Clubbing
Weight loss
Cervical/supraclavicular lymphadenopathy
Any features suggestive of metastases
Urgent referral should be made even without waiting for the CXR result if:
Smoker/ex-smoker over 40y with persistent haemoptysis
Stridor
Signs of superior vena cava obstruction (swelling of face and/or neck with raised JVP)
Urgent referral if:
Abnormal CXR
Normal CXR but suspicion of cancer remains (see BJGP paper above).
Sputum cytology is rarely helpful.
The remainder of the guidance is focused on investigation and management within secondary care.
Stopping smoking and lung cancer prognosis
I’ve always wondered whether there is any point discussing smoking cessation with people who have just been
diagnosed with lung cancer. So this systematic review and meta-analysis have been really helpful, because they
look at just this issue.
The systematic review looked at all papers that give prognostic data on those who continued to smoke compared with those who
gave up around the time of diagnosis (BMJ 2010;340:b5569).
Those who continued to smoke were more likely to die and had an increased risk of recurrence. Modelling of the
data suggests that:
For a hypothetical 65-year-old with newly diagnosed early non-small cell lung cancer:
Those who give up around diagnosis have a 70% chance of living for 5 years.
Those who continue to smoke have a 33% chance of living for 5 years.
For the same hypothetical patient, this time with early small cell lung cancer:
Those who give up smoking around diagnosis have a 63% 5-year survival.
Those who continue to smoke have a 29% 5-year survival.
Modelling suggests that the lives saved would be greater than expected through reduced cardiovascular deaths
alone, suggesting that the improvement is due in part to reduced cancer progression.
So what does this mean in practice?
This meta-analysis and systematic review suggest that encouraging smoking cessation in those with a new
diagnosis of lung cancer improves outcomes.
It really is worth encouraging people with early lung cancer to give up smoking!
Lung cancer
Trials of low dose CT screening are suggesting benefit to those at highest risk, but less
benefit to those at lower risk.
Do not be falsely reassured by a negative CXR if your clinical suspicion of cancer is
high! CXRs miss up to 10% of lung cancers!
Investigate if symptoms persist for more than 3w, or sooner in those with haemoptysis.
Be particularly suspicious of persistent haemoptysis in a smoker/ex-smoker aged over
40y. This warrants urgent referral even before the CXR is back.
Stopping smoking, even after a diagnosis of early lung cancer, is worthwhile.
Look back over the last 5 patients diagnosed with lung cancer in your practice. What learning
points can you identify? Could you share this with your team?
The Red Whale | GP Update Course – The one day course for GPs and GP Registrars, by GPs.
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