Calling All Men – Screening for Prostate Cancer Probably Does Save a Few Prostate Cancer Deaths

Two large randomised trials with 12 years follow-up.[1] [2] One shows reduction in prostate cancer deaths, the other produced a null result. But science cannot prove a null, and point estimates were favourable in both trials. Moreover, there were many differences in implementation of screening across the two large trials. So the authors of a recent study [3] amalgamated the individual research from each individual study and analysed the consolidated dataset to adjust for differences in screening intensity using a measure of the average time by which diagnosis is advanced by screening compared to not screening. This was calculated in different ways, but the results do suggest a screening effect on prostate cancer deaths of about 8%. Whether this translates into all-cause mortality is uncertain, as per a previous News Blog on this issue.[4] I was attracted to this paper, not only because prostate screening is a controversial and important public health issue, but also because it deals with a common scenario in contemporary clinical research – apparently contradictory trial results where one trial provides a null result and the other provides a positive result.

— Richard Lilford, CLAHRC WM Director

References:

  1. Schröder FH, Hugosson J, Roobol MJ, et al. Screening and prostate cancer mortality: results of the European Randomised Study of Screening for Prostate Cancer (ERSPC) at 13 years of follow-up. Lancet. 2014; 384: 2027-35.
  2. Pinsky PF, Prorok PC, Yu K, et al. Extended mortality results for prostate cancer screening in the PLCO trial with median follow-up of 15 years. Cancer. 2017; 123: 592-9.
  3. Tsodikov A, Gulati R, Heijnsdijk AEM, et al. Reconciling the Effects of Screening on Prostate Cancer Mortality in the ERSPC and PLCO Trials. Ann Intern Med. 2017; 164: 449-55.
  4. Lilford RJ. Thyroid Cancer: Another Indolent Tumour Prone to Massive Over Diagnosis. NIHR CLAHRC West Midlands News Blog. 24 March 2017.
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One thought on “Calling All Men – Screening for Prostate Cancer Probably Does Save a Few Prostate Cancer Deaths”

  1. Why is ’cause-specific death’ rather than ‘all-cause’ death as used in screening considered sufficient? It isn’t. All medical interventions cause harm (whether anxiety/ opportunity costs or mortality and morbidity, let alone the special harms of ‘overdiagnosis’). Some cause adequate benefit (ie the total benefit minus the harm). When it comes to our bank accounts we know we have to count money both in and out. Did I miss something or are we letting screening proponents get away with this sleight of hand?

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