On 2014 Feb 12, David Keller commented:

None

On 2014 Feb 12, David Keller commented:

Further arguments in support of PSA screening.

Evidence in favor of PSA screening for prostate cancer detection was summarized in a review by Allan and colleagues (1): “Based on the best available trials, we concluded that prostate cancer screening, specifically PSA, does reduce prostate cancer mortality. The number needed to screen to prevent one prostate cancer death at nine and 14 years of follow-up were 1410 and 293, from the ERSPC and Göteborg studies, respectively.... In comparison, the number needed to screen with mammography to prevent one breast cancer death in women ≥50 years of age is 1235 and 614 for 7 and 13 years, respectively. The number needed to screen with fecal occult blood testing to prevent one colorectal cancer death is 617 over 12 to 18 years. Prostate cancer screening, similar to the other accepted cancer screening programs, does not modify overall mortality."

Note that in the Goteborg study, 24% of the men invited to be screened never actually showed up to have a PSA drawn, yet they were included in the intention-to-treat analysis. If we subtract them from the results, then the number actually screened to prevent one death is reduced to 223. In the PLCO prostate cancer screening study, 52% of the “control” patients actually had PSA testing performed outside the study, and only 86% of patients in the screening arm were compliant with the PSA protocol. This severely contaminated data did not support PSA screening, which tells us little except to disregard any meta-analysis which includes PLCO.

In my letter, I pointed out that clinicians can improve the specificity of PSA screening by the following technique: when an elevated PSA occurs, repeat it a few times at short intervals and discard all but the lowest PSA for comparison to the biopsy threshold. This simple technique can spare many men from undergoing prostate biopsies, reducing potential harms from screening. Arguments against PSA screening often cite patient worry as a potential harm, which actually represents failure by clinicians to communicate the indolent behavior of many prostate cancers. Men offered screening should be informed that prostate cancers exhibit a range of behaviors, and often do not result in metastases or death.

Dr. Katz states that only 7% of men chose watchful waiting for localized prostate cancer in a recent registry, while 83% chose invasive treatments, despite the lack of convincing data to support the superiority of the latter. This again represents a failure of communication by the physicians involved. Patients are generally quite happy to avoid surgery when their clinician assures them it is not necessary or beneficial. We can increase the use of watchful waiting if we communicate effectively with our patients.

Finally, I wish to correct an omission from the last paragraph of my letter, which should have read: “We need a large trial of PSA measured every 3 months during the first year (to establish a baseline PSA)....”

1: Allan GM, Chetner MP, Donnelly BJ, Hagen NA, Ross D, Ruether JD, Venner P.Furthering the prostate cancer screening debate (prostate cancer specificmortality and associated risks). Can Urol Assoc J. 2011 Dec;5(6):416-21. doi:10.5489/cuaj.11063. PubMed PMID: 22154638; PubMed Central PMCID: PMC3235209.

On 2014 Feb 12, David Keller commented:

Further arguments in support of PSA screening.

Evidence in favor of PSA screening for prostate cancer detection was summarized in a review by Allan and colleagues (1): “Based on the best available trials, we concluded that prostate cancer screening, specifically PSA, does reduce prostate cancer mortality. The number needed to screen to prevent one prostate cancer death at nine and 14 years of follow-up were 1410 and 293, from the ERSPC and Göteborg studies, respectively.... In comparison, the number needed to screen with mammography to prevent one breast cancer death in women ≥50 years of age is 1235 and 614 for 7 and 13 years, respectively. The number needed to screen with fecal occult blood testing to prevent one colorectal cancer death is 617 over 12 to 18 years. Prostate cancer screening, similar to the other accepted cancer screening programs, does not modify overall mortality."

Note that in the Goteborg study, 24% of the men invited to be screened never actually showed up to have a PSA drawn, yet they were included in the intention-to-treat analysis. If we subtract them from the results, then the number actually screened to prevent one death is reduced to 223. In the PLCO prostate cancer screening study, 52% of the “control” patients actually had PSA testing performed outside the study, and only 86% of patients in the screening arm were compliant with the PSA protocol. This severely contaminated data did not support PSA screening, which tells us little except to disregard any meta-analysis which includes PLCO.

In my letter, I pointed out that clinicians can improve the specificity of PSA screening by the following technique: when an elevated PSA occurs, repeat it a few times at short intervals and discard all but the lowest PSA for comparison to the biopsy threshold. This simple technique can spare many men from undergoing prostate biopsies, reducing potential harms from screening. Arguments against PSA screening often cite patient worry as a potential harm, which actually represents failure by clinicians to communicate the indolent behavior of many prostate cancers. Men offered screening should be informed that prostate cancers exhibit a range of behaviors, and often do not result in metastases or death.

Dr. Katz states that only 7% of men chose watchful waiting for localized prostate cancer in a recent registry, while 83% chose invasive treatments, despite the lack of convincing data to support the superiority of the latter. This again represents a failure of communication by the physicians involved. Patients are generally quite happy to avoid surgery when their clinician assures them it is not necessary or beneficial. We can increase the use of watchful waiting if we communicate effectively with our patients.

Finally, I wish to correct an omission from the last paragraph of my letter, which should have read: “We need a large trial of PSA measured every 3 months during the first year (to establish a baseline PSA)....”

1: Allan GM, Chetner MP, Donnelly BJ, Hagen NA, Ross D, Ruether JD, Venner P.Furthering the prostate cancer screening debate (prostate cancer specificmortality and associated risks). Can Urol Assoc J. 2011 Dec;5(6):416-21. doi:10.5489/cuaj.11063. PubMed PMID: 22154638; PubMed Central PMCID: PMC3235209.