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Sunday, December 28, 2008

Blog Updates for December 2008

To wrap up 2008 there were over 40,000 page views of this blog this year. The 10 most visited pages on this blog (most visted first, second most visited second, etc.) were:

The Palpable Prostate
The Palpable Prostate: Prostate Cancer Calculators
The Palpable Prostate: Biochemical PSA Recurrence
The Palpable Prostate: ED After Prostatectomy - Part 1. Introduction
The Palpable Prostate: Yananow Place Name Table
The Palpable Prostate: PSA Doubling Time (PSADT) - Part 2. Calculating PSADT with Graphics
The Palpable Prostate: ED After Prostatectomy - Part 2. Rehabilitation
The Palpable Prostate: Urinary Incontinence
The Palpable Prostate: PSA Doubling Time (PSADT) - Part 1. Introduction & Use
The Palpable Prostate: Bradford Hill Criteria of Causation

The blog updates during December 2008 were:

Dec 23. On the Case Histories page we added: This case history appeared in the December 11, 2008 New England Journal of Medicine together with comments by three experts: [link].

Dec 23. On the Calculators page added: C. SWOP. A third site with an array of calculators including some not available at the above two is the site, also referred to as SWOP, of The Prostate Cancer Research Foundation is closely related to the Department of Urology of the Erasmus MC, University and Medical Centre of Rotterdam.
  • Risk indicator 1 is based on questions related to urinary frequency. It is assumed that no testing has yet been done.
  • Risk indicator 2 is based on the result of a PSA test.
  • The next three indicators are based on ultrasound results (0/1), digital rectal exam (0/1), prostate volume (ml) and PSA (ng/ml).
    • Risk indicator 3 allows a more precise prediction of a positive biopsy than indicator 2 because it includes the results of the rectal examination, the ultrasonography (hypoechogenic lesions yes or no?), and of the volume of the prostate determined at ultrasonography. Each of these parameters has independent value in predicting biopsy outcome (Roobol et al, Prostate 2006).
    • Risk indicator 4 is based on 10890 men who were previously screened, had a serum PSA < 4.0 ng/ml and were not biopsied. Of these men 1921 were biopsied 4 years later for PSA progression to = 3.0 ng/ml, 430 cancers were found (PPV 22.4%).
    • Risk indicator 5 is based on 989 men who were previously screened, were biopsied and had no cancer. These men were again biopsied 4 years later with PSA values = 3.0 ng/ml, 120 cancers were found (PPV 12.1%). Both, a negative previous screen and, more importantly, a prior negative biopsy significantly decrease the risk of a later positive biopsy.
  • Risk indicator 6 calculates the chance of having indolent prostate cancer which may not require immediate treatment. It uses Gleason Score, mm of cancer in biopsy, mm healthy tissue in biopsy, prostate volume (cc) and PSA (ng/ml).

December 21. In How Long Can Prostate Cancer Treatment be Delayed After Treatment we added: A recent NCI trial comparing immediate to delayed continuous hormone therapy concluded that there was no detectable difference between the two. See [PMID: 18823693] [NCI Trial Info] [NCI summary]. On the last link see the paragraph that starts "Immediate hormone therapy ..." that refers to EORTC-30846. The last link also refers to trials of intermittent hormone therapy with on and off again periods. The link concludes that the existing trials have been too small to base reliable conclusions on but it may be that all continuous therapy is ultimately rejected as a treatment in favor of intermittent therapy. The problem has been hypothesized to be that continuous therapy might selectively kill the weaker cancer cells undesirably allowing the more aggressive ones to dominate.

Dec 20. In Bradford Hill Criteria of Causation we added: The cause of inconsistent studies can sometimes be traced to an unaccounted for and possibly unknown factor whose presence affects the efficacy of the treatment. For example, Javier A. Menendez at the Catalan Institute of Oncology in Girona, Spain, and colleagues found that extra virgin olive oil was effective against breast cancer cells in HER2 positive individuals but not in HER2 negatives. At the time of the trials it was likely not known what the HER2 status of the subjects was but with this information new trials could be designed that stratified on HER2 analysing HER2 positive and negative subjects separately focusing on the subgroup, HER2 positives, where the effect is expected without dilution from the HER2 negative where no effect is expected. See [WebMD article] [PMID: 19094209].

Dec 20. On the Daily News line near the top of every page we added: Medical News Today

Dec 19. In Bradford Hill Criteria of Causation we added: The book Statistical Evidence in Clinical Trials by Stephen Simon suggests two other criteria that might be added to those of Bradford Hill: assessment of the possibility of fraud and of conflicts of interest. Regarding the latter see [PMID: 11900164] [Full Text] for a discussion of how one journal's editors discovered that authors not only had conflicts but that control was being exercised by pharmaceutical companies over the wording of their journal article submissions. Even worse [PMID: 18792536] and [PMID: 18413874] discuss actual ghostwriting of papers by industry sponsors.

Dec 19. In Testosterone Metabolism and Prostate Cancer we added: "Green tea catechin (-)-epigallocatechin gallate (EGCG) is a natural AR5 inhibitor. Flavonoids that were potent inhibitors of the type 1 5alpha-reductase include myricetin, quercitin, baicalein, and fisetin. Biochanin A, daidzein, genistein, and kaempferol were much better inhibitors of the type 2 than the type 1 isozyme. Several other natural and synthetic polyphenolic compounds were more effective inhibitors of the type 1 than the type 2 isozyme, including alizarin, anthrarobin, gossypol, nordihydroguaiaretic acid, caffeic acid phenethyl ester, and octyl and dodecyl gallates." (quotes from [PMID: 11931850])

Dec 18. In the Urinary Incontinence post added: In the right margin of this article entitled Pelvic Power (taken from Our Voice, 2008, 4(4)) physiotherapist Bill Landry describes 3 pelvic floor exercises and recommends performing them daily for 6 months after the catheter is removed and once or twice a week for the rest of your life after that. They should be performed "in postures/positions where leakage occurs" in order to get maximum benefit.

Dec 18. Pathology. A rule of thumb is that for each cubic centimeter (cc) of benign prostate tissue that 0.067 ng/ml of PSA will be produced. Thus for a prostate of 40cc (this is the volume of the prostate, not the volume of the tumor) one would expect a PSA of 40 x 0.067 = 2.68 ng/ml so if the actual PSA were 4.0 ng/ml then there is 4.0 - 2.68 = 1.32 ng/ml that is unexplained and might be due to cancer cells or other factor listed here. [link]. In a December 2008 paper Kato et al devised the following formulas for tumor volume (cc) and percent tumor volume as a function of PSA (ng/ml):

Tumor Volume (cc) = 3.476 + 0.302 x PSA

Tumor Volume (%) = 11.331 + 0.704 x PSA

[PMID: 19060997] [Full Text]

Dec 18. In Testosterone Metabolism and Prostate Cancer we added this [Friedman comment].

Dec 15. In Bradford Hill Criteria of Causation we added the following example of temporality: One patient remarked that those with more aggressive prostate cancer seemed weak but were they weak before they had it or did the cancer or treatment make them weak (reverse causality)? Which one came first would be essential to know.

Dec 15. In Advice to the Newly Diagnosed we added in reference to treatment decisions: Dr. Cary Presant makes similar remarks.

Dec 15. In Advice to the Newly Diagnosed we added: however, the situation is not actually so clear cut and as discussed in [PMID: 15717036] [Full Text] the value of randomized controlled trials may be over rated.

Dec 14. In Advice to the Newly Diagnosed we added: The book Statistical Evidence in Medical Trials by Stephen Simon has excellent non-technical coverage of how to understand medical research. It is intended for doctors to help them assess which advances to incorporate into their practice but its very easy to read by anyone. Simon's articles in the Journal of Andrology provide a portion of the material.

Dec 12. On the Daily News line near the top of every page we added: ScienceDaily

Dec 8. In Links section in the right margin we added this link to the November 2008 AUA Best Practices on Cryo statement: [AUA Cryo]. Also added this in the Treatments: line under (AUA) after [Cryo].

Dec 7. Removed one blog in the Blogs line under Links to the right whose volume of postings seems to have dropped off.

Dec 2. In Links section in the right margin on the Treatments line we added this link to a news article about 2008 report of UK agency NCEPOD, (NCEPOD), entitled Systemic Anti-Cancer Therapy: For better, for worse? which investigated deaths caused by chemotherapy : [link], (NCEPOD). The news article has a link to the NCEPOD site where the complete report and various summaries can be found.

Dec 2. In Choosing a Surgeon - Part I. Considerations, Choosing a Surgeon - Part I. Considerations we added: In December 2008 Andonian et al., at the 26th World Congress of Endourology (WCE) in Shanghai presented evidence of measurable changes in brain function among more experienced surgeons. See [link].

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