Re: Does early diagnosis really save lives?
3 July 2012
Des Spence’s claim that attempts to diagnose disease earlier amount to “bad screening and the worst science” is a sweeping generalisation that is false in numerous situations. Surely he has completely lost the plot! Early diagnosis is what the public expects of its doctors and is the basis of the practice of medicine, with the clinical identification of features of putative disease leading to special investigations. Who would ever congratulate a doctor for late diagnosis? There are innumerable instances when late diagnosis is associated with adverse outcomes, to which our defence organisations regularly testify. HIV infection, tuberculosis, skin cancers, type 1 diabetes are just a few cases that spring to mind. Even in regard to the recent national campaign to improve early diagnosis of lung cancer, which seems to have stimulated his article, the statement is premature and grossly nihilistic. Several statements in support of his argument are factually incorrect: having symptoms does not imply incurable disease in lung cancer; there is no doubt that cough is a symptom of this disease -and it is a key one because of its particular association with better outcome;1 Hamilton has studied and reported on the predictive value of symptoms in lung cancer.2
More seriously, Spence has conflated screening with early diagnosis in order to damn the latter. Early identification of symptomatic disease is an entirely different proposition to the screening of asymptomatic patients. In the case of lung cancer, screening (both with plain radiography and computed tomography) is bedevilled by the serious problem of overdiagnosis, i.e. the identification of clinically silent cases of disease that would not cause problems in the subject’s lifetime. Therefore, diagnosis currently rests on the identification of symptoms, which do serve to imply “real” disease.
Moving on to address lung cancer specifically, is Dr Spence is suggesting we ought not to investigate someone who has haemoptysis, or perhaps wait for even more specific features to emerge, with the patient becoming frail and ill, when the diagnosis is easy, but its value to the patient so much less? The question at hand is how hard we should try. For example, persistent haemoptysis and stridor in a cachectic older smoker will very likely reveal lung cancer that is incurable. By investigating more patients with lower probabilities of cancer being present, when patients remain fit and well, with less specific, common but potentially sinister symptoms that might not be severely troubling to them, such as a new or altered cough, the hit rate will be lower but the chance finding curable disease that much higher. This message has been accepted by the public and doctors in relation to other cancers. For example, every woman knows that she should have a lump in the breast investigated even if she is otherwise well. Why is it that almost uniquely, clinicians seem only to think of lung cancer only when the patient appears to be unwell? In this way, the poor outcomes of lung cancer become a self-fulfilling prophecy.
UK lung cancer patients have a substantially poorer outcome than in most other developed economies in Western Europe and North America,3 which implies that the outcomes we see are not inherent in the disease biology, but relate to other factors, that may be modifiable. Because UK patients present with more advanced disease, an important issue appears to be the late identification of patients in primary care. This is may reflect public ignorance of the symptoms of lung cancer and a reluctance by UK GPs to comply with NICE guidance on when to refer patients with red flag symptoms for a chest X-ray. This is to say we should try harder.
Whilst the primary objective of early diagnosis initiatives is to achieve a stage shift, thereby increasing cure rates, there are other benefits to early diagnosis. Depressingly frequently, patients present for the first time to secondary care with extensive disease and poor performance status, often as medical emergencies, and have very poor outcomes. These patients frequently die in hospital, robbing them and their relatives of the opportunity properly to make preparations for their death. When patients are diagnosed only when they have become ill and frail, opportunities for treatments with proven palliative and life-prolonging value, including palliative care, chemotherapy, radiotherapy and targeted therapies, are missed. Whilst Des Spence is arguing against attempting early diagnosis, is he really arguing for this?
The Doncaster study4 sought to address the public ignorance and the poor observance of NICE guidance on when to do a chest X-ray in primary care, head on. Public awareness was raised and there was a significant 26% increase in the number of chest X-rays done. Due to small numbers, the positive effects seen on number of lung cancers diagnosed failed to reach statistical significance and the study was not powered to show an improvement in the number of patients identified with curable disease. Dr Spence is quite incorrect though to say the study showed “no impact on the presentation of treatable lung cancer.” In a follow up study, we have again found beneficial trends, including a 10% increase in the number of cases found (implying catch-up and that earlier diagnosis was occurring) and a 50% increase in the number of patients diagnosed with stage 1 disease.
I believe the national early diagnosis campaign therefore represents a bold and exciting experiment to test the hypothesis that increased awareness by the public and their doctors can lead to earlier diagnosis and improve disease outcomes, at least up to international standards.
1. Buccheri G,.Ferrigno D. Lung cancer: clinical presentation and specialist referral time. European Respiratory Journal 2004;24:898-904.
2. Hamilton W, Peters TJ, Round A, Sharp D. What are the clinical features of lung cancer before the diagnosis is made? A population based case-control study. Thorax 2005;60:1059-65
3. Coleman MP, Forman D, Bryant H, Butler J, Rachet B, Maringe C et al. Cancer survival in Australia, Canada, Denmark, Norway, Sweden, and the UK, 1995-2007 (the International Cancer Benchmarking Partnership): an analysis of population-based cancer registry data. Lancet 2011;377:127-38.
4. Athey VL, Suckling RJ, Tod AM, Walters SJ, Rogers TK. Early diagnosis of lung cancer: evaluation of a community-based social marketing intervention. Thorax 2012;67:412-417.
Competing interests: None declared
Doncaster Royal Infirmary, Armthorpe Road Doncaster DN2 5LT
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