Study raises five questionsBMJ 2011; 342 doi: https://doi.org/10.1136/bmj.d3698 (Published 14 June 2011) Cite this as: BMJ 2011;342:d3698
- Harriet E Burn, foundation year 1 doctor general surgery1,
- Sheila Fraser, SpR general surgery1,
- Sabapathy Balasubramanian, consultant general surgeon1
Sandblom and colleagues’ 20 year follow-up study of prostate cancer screening raises five questions.1
(1) Screening test methods evolved during the study. Why were men from the screening group aged 69 or older excluded only from the fourth screening session rather than consistently throughout?
(2) Digital rectal examination was the first screening test, prostate specific antigen (PSA) testing being included only in the third screening session. In addition to the combined utility of rectal examination and PSA testing, what are the individual contributions of these tests to the early detection of prostate cancer?
(3) Overdiagnosis of indolent tumours has been rightly emphasised as a significant drawback to screening, but unnecessary investigations, the need for early repeat testing, and patient anxiety from a false positive result of examination or testing have not. How many false positive results arise from PSA testing, rectal examination, and the two combined? We could not deduce whether the combined tests reduced or increased the number of false positive results.
(4) What are the predictive values of the individual tests and their combination? We could not calculate them from the information given.
(5) Figures 2-4 show overall and disease specific mortality only in patients diagnosed with prostate cancer in the two groups, which may be misleading. What are the rates in the two groups overall as per allocation?
Cite this as: BMJ 2011;342:d3698
Competing interests: None declared.