Skip to main content

How to Interpret Numeric Results in Publications?

  • Chapter
  • First Online:
Book cover Management of Prostate Cancer
  • 1261 Accesses

Abstract

Massive amounts of new literature are published each year, providing varied levels of evidence to the medical urology community. Despite the peer-review processes in place with most journals and congresses and in spite of the widespread adoption of international reporting guidelines such as CONSORT, the new evidence is unfortunately not always objectively and unbiasedly presented. Intentional or more often, unintentional misuse or misinterpretation of statistical evidence, inadequate trial methodology, the natural tendency of humans to seek confirmation of their prior beliefs and to give more focus to the more statistically significant findings are the most common flaws in the medical literature. In this chapter, we will illustrate some of these pitfalls, with the aim to exercise the reader to using their critical thinking when appraising published research findings. We will use published reports comparing therapeutic interventions against prostate cancer as examples because modern clinical trials are becoming increasingly complex and therefore more difficult to appraise for the non-statistically trained reader.

This is a preview of subscription content, log in via an institution to check access.

Access this chapter

Chapter
USD 29.95
Price excludes VAT (USA)
  • Available as PDF
  • Read on any device
  • Instant download
  • Own it forever
eBook
USD 89.00
Price excludes VAT (USA)
  • Available as EPUB and PDF
  • Read on any device
  • Instant download
  • Own it forever
Hardcover Book
USD 119.99
Price excludes VAT (USA)
  • Durable hardcover edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info

Tax calculation will be finalised at checkout

Purchases are for personal use only

Institutional subscriptions

References

  1. Anderson JR, Cain KC, Gelber RD. Analysis of survival by tumor response. J Clin Oncol. 1983;1(11):710–9.

    CAS  PubMed  Google Scholar 

  2. Armstrong AJ, Febbo FG. Using surrogate endpoints to predict clinical benefit in men with castration-resistant prostate cancer: an update and review of the literature. Oncologist. 2009;14(8):816–27.

    CAS  PubMed  Google Scholar 

  3. Bedard PL, Kryzanowska MK, Pintilie M, et al. Statistical power of negative randomized controlled trials presented at American Society for Clinical Oncology Annual Meetings. J Clin Oncol. 2007;25(23):3482–7.

    Article  PubMed  Google Scholar 

  4. Bhattacharya S, Fyfe G, Gray RJ, et al. Role of sensitivity analyses in assessing progression-free survival in late-stage oncology trials. J Clin Oncol. 2009;27(35):5958–64.

    Article  PubMed  Google Scholar 

  5. Bolla M, de Reijke THM, Van Tienhoven G, et al. Duration of androgen suppression in the treatment of prostate cancer. N Engl J Med. 2009;364(24):2516–27.

    Article  Google Scholar 

  6. Bolla M, van Poppel H, Collette L, et al. Postoperative radiotherapy after radical prostatectomy: a randomized controlled trial (EORTC trial 22911). Lancet. 2005;366(9485):572–8.

    Article  PubMed  Google Scholar 

  7. Bolla M, Van Tienhoven G, Warde P, et al. External irradiation with or without long-term androgen suppression for prostate cancer with high metastatic risk:10-year results of an EORTC randomised study. Lancet Oncol. 2010;11(11):1066–73.

    Article  CAS  PubMed  Google Scholar 

  8. Breau RH, Carnat TA, Gaboury I. Inadequate statistical power of negative clinical trials in the urological literature. J Urol. 2006;176(1):263–6.

    Article  PubMed  Google Scholar 

  9. Briganti A, Karnes JR, Da Pozzo LF, et al. Two positive nodes represent a significant cut-off value for cancer specific survival in patients with node positive prostate cancer. A new proposal based on a two-institution experience on 703 consecutive N+ patients treated with radical prostatectomy, extended pelvic lymph node dissection and adjuvant therapy. Eur Urol. 2009;55(2):261–70.

    Article  PubMed  Google Scholar 

  10. Budiharto T, Perneel C, Haustermans K, et al. A multi-institutional analysis comparing adjuvant and salvage radiation therapy for high-risk prostate cancer patients with undetectable PSA after prostatectomy. Radiother Oncol. 2010;97(3):474–9.

    Article  PubMed  Google Scholar 

  11. Carroll KJ. Analysis of progression-free survival in oncology trials: some common statistical issues. Pharm Stat. 2007;6(2):99–113.

    Article  PubMed  Google Scholar 

  12. Catton C, Gospodarowicz M, Warde P, et al. Adjuvant and salvage radiation therapy after radical prostatectomy for adenocarcinoma of the prostate. Radiother Oncol. 2001;59(1):51–60.

    Article  CAS  PubMed  Google Scholar 

  13. Collette L. Prostate-specific antigen (PSA) as a surrogate endpoint for survival in prostate cancer clinical trials. Eur Urol. 2008;53(1):6–9.

    Article  PubMed  Google Scholar 

  14. Cookson MS, Aus G, Burnett AL, et al. Variation in the definition of biochemical recurrence in patients treated for localized prostate cancer: the American Urological Association prostate guidelines for localized prostate cancer update panel report and recommendations for a standard in the reporting of surgical outcomes. J Urol. 2007;177(2):540–5.

    Article  CAS  PubMed  Google Scholar 

  15. D’Agostino Jr RB. Propensity score methods for bias reduction in the comparison of a treatment to a non-randomized control group. Stat Med. 1998;17(19):2265–81.

    Article  PubMed  Google Scholar 

  16. D’Amico AV, Denham JW, Bolla M, et al. Short- vs long-term androgen suppression plus external beam radiation therapy and survival in men of advanced age with node negative high risk adenocarcinoma of the prostate. Cancer. 2007;109(10):2004–10.

    Article  PubMed  Google Scholar 

  17. Dancey JE, Dodd LE, Ford R, et al. Recommendations for the assessment of progression in randomized cancer treatment trials. Eur J Cancer. 2009;45(2):281–9.

    Article  CAS  PubMed  Google Scholar 

  18. Denham JW, Steigler A, Wilcox C, et al. Time to biochemical failure and prostate-specific antigen doubling time as surrogates for prostate cancer-specific mortality: evidence from the TROG 96.01 randomised controlled trial. Lancet Oncol. 2008;9(11):1058–68.

    Article  CAS  PubMed  Google Scholar 

  19. Dodd LE, Korn EL, Freidlin B, Gray R, Bhattacharya S. An audit strategy for progression-free survival. Biometrics. 2011;67(3):1092–9.

    Article  PubMed  PubMed Central  Google Scholar 

  20. Engel J, Bastian PJ, Baur H, et al. Survival benefit of radical prostatectomy in lymph node positive patients with prostate cancer. Eur Urol. 2010;57(5):754–61.

    Article  PubMed  Google Scholar 

  21. European Medicines Agency. Guideline on the investigation of subgroups in confirmatory clinical trials. EMA/CHMP/539146/2013. 2014. Available at: http://www.ema.europa.eu/docs/en_GB/document_library/Scientific_guideline/2014/02/WC500160523.pdf. Accessed 19 Apr 2016.

  22. European Medicines Agency. Points to consider on multiplicity issues in clinical trials. CPMP/EWP/908/99. 2002. Available at: http://www.ema.europa.eu/docs/en_GB/document_library/Scientific_guideline/2009/09/WC500003640.pdf. Accessed 19 Apr 2016.

  23. European Union. Regulation (EU) 536/2014 of the European Parliament and of the Council of 16 April 2014 on clinical trials on medicinal products for human use, and repealing Directive 2001/20/EC. Available at: http://ec.europa.eu/health/files/eudralex/vol-1/reg_2014_536/reg_2014_536_en.pdf. Accessed 19 Apr 2016.

  24. Freidlin B, Korn EL, Hunsberger S, et al. Proposal for the use of progression-free survival in unblinded randomized trials. J Clin Oncol. 2007;25(15):2122–6.

    Article  PubMed  Google Scholar 

  25. Gignac GA, Morris MJ, Heller G, et al. Assessing outcomes in prostate cancer clinical trials: a twenty-tirst century tower of babel. Cancer. 2008;113(5):966–74.

    Article  PubMed  PubMed Central  Google Scholar 

  26. Goeman JJ, Solari A. Multiple hypothesis testing in genomics. Stat Med. 2014;33(11):1946–78.

    Article  PubMed  Google Scholar 

  27. Howland RH. What you see depends on where you’re looking and how you look at it: publication bias and outcome reporting bias. J Psychosoc Nurs Ment Health Serv. 2011;49(8):13–5. J Psychosoc Nurs Ment Health Serv. 15:1–3.

    Google Scholar 

  28. ICECaP working group. The development of intermediate clinical endpoints in cancer of the prostate (ICECaP). J Natl Cancer Inst. 2015;107(12):1–8.

    Google Scholar 

  29. Lin K, Lee SP, Steinberg ML. Selection bias clouds apparent benefit of longer hormone duration. J Clin Oncol. 2010;28(5):e79.

    Article  PubMed  Google Scholar 

  30. OCEBM Levels of Evidence Working Group*. “The oxford 2011 levels of evidence”. Oxford centre for evidence-based medicine. http://www.cebm.net/index.aspx?o=5653. Last Accessed 19 Apr 2016.* OCEBM Table of Evidence Working Group = Jeremy Howick, Iain Chalmers (James Lind Library), Paul Glasziou, Trish Greenhalgh, Carl Heneghan, Alessandro Liberati, Ivan Moschetti, Bob Phillips, Hazel Thornton, Olive Goddard and Mary Hodgkinson.

  31. Panageas KS, Ben-Porat L, Dickler MN, et al. When you look matters: the effect of assessment schedule on progression-free survival. J Natl Cancer Inst. 2007;99(6):428–32.

    Article  PubMed  Google Scholar 

  32. Patel AR, Stephenson AJ. Radiation therapy for prostate cancer after prostatectomy: adjuvant or salvage? Nat Rev Urol. 2011;8(7):385–92.

    Article  PubMed  Google Scholar 

  33. Ray ME, Bae K, Hussain MH, Hanks GE, et al. Potential surrogate endpoints for prostate cancer survival: analysis of a phase III randomized trial. J Natl Cancer Inst. 2009;101(4):228–36.

    Article  PubMed  PubMed Central  Google Scholar 

  34. Roach MI, Hanks G, Thames HJ, et al. Defining biochemical failure following radiotherapy with or without hormonal therapy in men with clinically localized prostate cancer: recommendations of the RTOG–ASTRO Phoenix Consensus Conference. Int J Radiat Oncol Biol Phys. 2006;65(4):965–74.

    Article  PubMed  Google Scholar 

  35. Rui Wang MS, Lagakos SW, Ware JH, et al. Statistics in medicine – reporting of subgroup analyses in clinical trials. N Engl J Med. 2007;357(21):2189–94.

    Article  PubMed  Google Scholar 

  36. Sandler HM, Pajak TF, Hanks GE, et al. Can biochemical failure (ASTRO definition) be used as a surrogate endpoint for prostate cancer survival in phase III localized prostate cancer clinical trials? Analysis of RTOG protocol 92–02. J Clin Oncol. 2003;22:381 (abstract 1529).

    Article  Google Scholar 

  37. Scher HI, Morris MJU, Stadler WM, et al. Trial design and objectives for castration-resistant prostate cancer: updated recommendations from the Prostate Cancer Clinical Trials Working Group 3. J Clin Oncol. 2016;34(12):1402–18.

    Article  PubMed  Google Scholar 

  38. Schroeder FH, Whelan P, de Reijke TM, et al. Metastatic prostate cancer treated by flutamide versus cyproterone acetate: final analysis of the European Organisation for Research and Treatment of Cancer (EORTC) protocol 30892. Eur Urol. 2004;45(4):457–64.

    Article  CAS  Google Scholar 

  39. Sharrock G, Graf C, Fitzpatrick JM. The role of ethical publishing in promoting the evidence-based practice of urology. World J Urol. 2011;29(3):319–24.

    Article  PubMed  Google Scholar 

  40. Sonpavde G, Pond GR, Armstrong AJ, et al. Radiographic progression by Prostate Cancer Working Group (PCWG)-2 criteria as an intermediate endpoint for drug development in metastatic castration-resistant prostate cancer. BJU Int. 2014;114(6b):E25–31.

    Article  PubMed  Google Scholar 

  41. Souhami L, Bae K, Pilepich M, et al. Impact of the duration of adjuvant hormonal therapy in patients with locally advanced prostate cancer treated with radiotherapy: a secondary analysis of RTOG 85-31. J Clin Oncol. 2009;27(13):2137–43.

    Article  PubMed  PubMed Central  Google Scholar 

  42. Souhami L, Bae K, Sandler H. Reply to Collette et al. and Tangen et al. J Clin Oncol. 2009;27(33):e204.

    Article  Google Scholar 

  43. Studer UE, Collette L, Sylvester R. Can radical prostatectomy benefit patients despite the presence of regional metastases? Eur Urol. 2010;57(5):762–3.

    Article  PubMed  Google Scholar 

  44. Taylor N, Kelly JF, Kuban DA. Adjuvant and salvage radiotherapy after radical prostatectomy for prostate cancer. Int J Radiat Oncol Biol Phys. 2003;56(3):755–63.

    Article  CAS  PubMed  Google Scholar 

  45. Thompson IM, Tangen CM, Paradelo J, et al. Adjuvant radiotherapy for pathologically advanced prostate cancer: a randomized trial. JAMA. 2006;296(19):2329–35.

    Article  CAS  PubMed  Google Scholar 

  46. Trabulsi EJ, Valicenti RK, Hanlon AL, et al. A multi-institutional matched-control analysis of adjuvant and salvage postoperative radiation therapy for pT3–4N0 prostate cancer. Urology. 2008;72(6):1298–304.

    Article  PubMed  PubMed Central  Google Scholar 

  47. U.S. Department of Health and Human Services Food and Drug Administration. Guidance for industry clinical trial endpoints for the approval of cancer drugs and biologics. 2007. Available at: http://www.fda.gov/downloads/Drugs/Guidances/ucm071590.pdf. Accessed 19 Apr 2016.

  48. Valicenti R, Deslivio M, Hanks G, et al. Posttreatment prostatic-specific antigen doubling time as a surrogate endpoint for prostate cancer-specific survival: an analysis of Radiation Therapy Oncology Group Protocol 92–02. Int J Radiat Oncol Biol Phys. 2006;66(4):1064–71.

    Article  PubMed  Google Scholar 

  49. Wiegel T, Bottke D, Steiner U, et al. Phase III postoperative adjuvant radiotherapy after radical prostatectomy compared with radical prostatectomy alone in pT3 prostate cancer with postoperative undetectable prostate- specific antigen: ARO 96-02/AUO AP 09/95. J Clin Oncol. 2009;27(18):2924–30.

    Article  PubMed  Google Scholar 

  50. Wunsch H, Linde-Zwirble W, Angus DC. Methods to adjust for bias and confounding in critical care health services research involving observational data. J Crit Care. 2006;21(1):1–7.

    Article  PubMed  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Laurence Collette .

Editor information

Editors and Affiliations

Rights and permissions

Reprints and permissions

Copyright information

© 2017 Springer International Publishing Switzerland

About this chapter

Cite this chapter

Collette, L. (2017). How to Interpret Numeric Results in Publications?. In: Bolla, M., van Poppel, H. (eds) Management of Prostate Cancer. Springer, Cham. https://doi.org/10.1007/978-3-319-42769-0_25

Download citation

  • DOI: https://doi.org/10.1007/978-3-319-42769-0_25

  • Published:

  • Publisher Name: Springer, Cham

  • Print ISBN: 978-3-319-42768-3

  • Online ISBN: 978-3-319-42769-0

  • eBook Packages: MedicineMedicine (R0)

Publish with us

Policies and ethics