Sunday, November 30, 2008
Blog Updates for November 2008
Nov 28. Added to the Treatments: line in the Links section to the right this link to Washington Post CyberKnife article: [CyberK]
Nov 28. Added to the Medical/Uro line in the Links section to the right this link to [Medline+]
Nov 28. Added the following information on the new HHS exercise and physical fitness guidelines on the Guidelines - US line in the Links section to the right: HHS Exercise (Medline+) (summary) (podcast)
Nov 28. In Questions to Ask Doctor added: Another source of general questions is this 2 page brochure from the Ontario Hospital Association (OHA) and the accompanying wallet card. A number of related brochures (mostly the same ones but in different languages) can be found on the OHA site here.
Nov 28. In Advice to the Newly Diagnosed we added: The Primer began as a brief introductory article by Donna Pogliano and evolved into the present book which is widely regarded as the most in depth and best patient-oriented book among patient groups.
Nov 26. In Advice to the Newly Diagnosed we added: Another problem is the significant delay in initiating a trial. See editorial in December 2008 Nature Clinical Practice Oncology [link].
Nov 24. In Advice to the Newly Diagnosed we added: A set of videos which take a similar approach to localized prostate cancer can be found [here]. At the same site there are a number of related videos on treatment choice including a video on locally advanced cancer, metastatic disease and other topics.
Nov 24. In How Healthy Men Can Reduce Their Risk and in PSA Screening and Early Detection. Part 3. Current Environment we added: A trial of 220,000 men in 8 countries, The European Randomised Study of Screening for Prostate Cancer [ESRPC], is currently underway and preliminary results suggest that screen detected prostate cancer has more favourable prognostic indicators that non-screen detected prostate cancer, but as yet no mortality advantage to screening has been shown [PMID: 18774469]. "The ERSPC trial has sufficient power to detect a significant difference in prostate cancer mortality between the two arms if the true reduction in mortality by screening is 25% or more (or, if contamination remains limited to 10 % if the true effect is 20 % or more). These results can be expected between 2008 and 2010." [ESRPC].
Nov 24. In Links section to the right on the Webcasts line we added: [PV] which refers to Dr. Gerald Chodak's Prostate Videos site. This site contains patient-oriented videos on prostate cancer.
Nov 24. In Advice to the Newly Diagnosed we added: It is important to distinguish among the different types of study. Randomized controlled trials are the best for application to patient situations whereas epidemiological studies are best used to generate hypotheses (rather than generate evidence) which randomized controlled studies can then attempt to verify in order to generate scientific evidence. A set of videos addressing this can be found on ProstateVideos.
Nov 24. In Lycopene, Selenium and Vitamin E in Combination we added: A 2008 animal study that examined the effect of combined selenium and isoflavones on rats also concluded that taking them together had a large favorable effect on the amount later detected in the blood stream relative to separate administration of the two. See [PMID: 19000315] [provisional text].
Nov 24. In PSA Screening and Early Detection - Part 3. Current Environment we add the following: National Health Service, UK - See Summary. The UK does not have a national program for PSA screening although screening is done on an opportunistic basis sometimes. See [link] for more information on prevalence of PSA testing and [PMID: 19021912] [provisional partial text] for a related study published in BMC Urology 2008. That study mentions among other points that even when PSA tests for screening is done the cutoff points used vary substantially from one doctor to another. (The UK Department of Health recommends the use of age-specific cutoffs of 3.0 for men aged 50-59, 4.0 for men 60-69 and 5.0 for men 70 and older. See [booklet] and [summary sheet].)
Nov 22. On the Case Histories page we added some cautions: Although reading about others' experience is very helpful the reader should be aware of several limitations which may include: (1) the information should be regarded with caution particularly when trying to decide among treatments as there is a human tendency to justify one's decisions. As a result it is common that prostate cancer patients support the treatment they chose over other treatments to an unreasonable degree (2) surgery takes effect immediately and also has the worst side effects immediately whereas radiation has relatively benign immediate side effects but over the period of several months or years as the radiation kills the prostate cancer cells the side effects kick in. As a result accounts which describe the side effects of radiation immediately after treatment cannot be used in terms of understanding the long term impact. (3) the reliability of patient accounts may vary.
Nov 22. In Bradford Hill Criteria of Causation we added the following example of their application to a paper on the beneficial affect of fish intake on prostate cancer:
We apply the Bradford Hill criteria to the effect of fish intake on survival among those diagnosed with prostate cancer.
In a 22 year prospective cohort study among 20,167 men participating in the Physician's Health Study who were free of cancer in 1983 found that 2161 men were later diagnosed with prostate cancer and 230 died of prostate cancer. A November 2008 study published in the American Journal of Clinical Nutrition [PMID: 18996866] [Partial Text] has concluded that fish "intake is unrelated to prostate cancer incidence" (consistent with prior studies); however, they also found that "Higher intakes of fish, particularly dark meat fish, and seafood n-3 fatty acids were related to lower prostate cancer mortality among the men diagnosed with prostate cancer." We examine this latter finding in terms of the Bradford Hill criteria:
Strength. The finding was quite strong as "survival analysis among the men diagnosed with prostate cancer revealed that those consuming fish greater than or equal to 5 times/wk had a 48% lower risk of prostate cancer death than did men consuming fish less than once weekly [relative risk (RR) = 0.52; 95% CI: 0.30, 0.91; P for trend = 0.05]."
Consistency. The study appears to be consistent with related results. From the paper: "In a recent small pilot randomized trial, men assigned to a study diet that emphasized, among other changes, increased intake of n-3 fatty acid-rich fish, had an increase in PSA doubling time [PMID: 9182974] [Full Text]. Similarly, the studies that previously reported fish or long-chain n-3 fatty acid intake to decrease prostate cancer risk, including our previous work [PMID: 17585059], have generally reported stronger associations with advanced stage [PMID: 10584888], [PMID: 15213050] [Full Text], [PMID: 15495177], clinically aggressive [PMID: 17585059], metastatic [PMID: 12540506] [Full Text], or lethal [PMID: 11403817] disease, which suggests that these dietary factors may have a role in reducing disease progression or mortality.
Temporality. The diet in the study was measured at baseline -- that is, at the beginning of the study when the patients did not have prostate cancer.
Biological Plausibility. The paper points out the biological plausibility as follows: "Laboratory data also suggest a role of marine n-3 fatty acids in reducing prostate cancer progression and mortality. Eicosapentaenoic acid, and to a greater extent its 15-LOX metabolite 15-HEPE, suppress the proliferation of multiple prostate cancer lines and the generation of COX-2 and 5-LOX metabolites of arachidonic acid [PMID: 15850718] that are known to increase proliferation, tumor cell survival, and angiogenesis[PMID: 15159222] [Full Text, [PMID: 16289380], [PMID: 9789062], [Full Text] , [PMID: 9199209]. Moreover, in a mouse model simulating prostate cancer recurrence after radical prostatectomy, mice fed an eicosapentaenoic acid precursor had reduced tumor recurrence, increased PSA doubling time, and decreased proliferation and increased apoptosis in recurrent tumor cells (14) Likewise, mice fed eicosapentaenoic acid in a model of hormone ablation therapy showed improved response to therapy (higher tumor apoptosis-to-mitosis ratios) and decreased progression into androgen independence (45)."
Coherence. The fact that fish intake seems unrelated to prostate cancer risk yet related to progression might seem contradictory yet observations that prostate cancer takes on different characteristics at different stages of its progression mean that this is certainly a possibility. See Willett Divides Prostate Cancer into Four. On the other hand, correlations between omega-3 fatty acids in the blood and fish intake were high.
Specificity. The study did attempt to control for other possible influences of prostate cancer mortality including "age at prostate cancer diagnosis; BMI; physical activity; intakes of alcohol, tomato products, and dairy products; smoking; race; use of multivitamins; use of vitamin E supplements; random assignment to aspirin or ß-carotene; and tumor stage and grade at diagnosis". It was unable to adjust for energy (calorie) intake but since it did adjust for BMI this can be considered a reasonable surrogate."
Experimental Evidence. This was not a randomized controlled study so the evidence must be considered as suggestive only. (Actually the data is from a randomized trial for asprin and beta carotene but not for this purpose so relative to this purpose it was not randomized.)
The strength of association, consistency with other studies and biological plausibility suggest mean that the study in question is highly suggestive of reduced fat intake having a desirable effect on prostate cancer survival among those diagnosed with prostate cancer.
Nov 22. Added link to 2008 presentation on HIFU labelled (2) after the first HIFU link on the Treatments link in the Links section to the right. See (2)
Nov 22. Added link to 2008 presentation on cryotherapy labelled (2) after the first cryotherapy link on the Treatments line in the Links section to the right. See (2) .
Nov 22. Added Pubmed (adv search) to the Medical/Uro line of links in the Links section to the right.
Nov 22. Added this info on chemotherapy to the Treatment Alternatives line of the Links seciton to the right: [chemo] (2)
Nov 21. In RP vs LRP vs RLRP. Part 3 we add this reference to a [New York Times blog] article on disappointment after robotic surgery.
Nov 21. In Lymph Node Dissection SLN LND is commonly practiced in breast cancer but despite its usefulness as a predictor of cancer specific survival [PMID: 18838212] does not appear to have found its way into standard practice in prostate cancer according to the blog of [Dr. Glode].
Nov 21. We have added the New York Times wellness blog to our blog list in the right margin. See the Blogs line under the Links section.
Nov 20. In Lycopene, Selenium and Vitamin E in Combination we added: The November 20, 2008 New York Times' blog ran a story summarizing the latest news: [link].
Nov 15. In PSA Screening and Early Detection Part 2 we add: PSA is decreased by statins which are cholesterol lowering drugs. "For every 10% decrease in LDL after starting a statin, PSA levels declined by 1.64." See [PMID: 18957682] and [PMID: 18957671] [Full Text].
Nov 15. In PSADT Part 1 we add: On the other hand in an October 2008 study of 199 subjects, PSAV predicted repeat biopsy results better than PSADT [PMID: 18990146].
Nov 9. In AUA 2007 Conference Summaries we added this link summarizing the AUA 2008 meeting: [Medscape]
Nov 9. In Choosing a Surgeon - Part I. Considerations, Choosing a Surgeon - Part I. Considerations we added: See [PMID: 11948274] and this [presentation] or [Flash version].
Nov 7. Although the expected AUA 2008 PSA guidelines are not out yet we have added a pointer to an article about them in the Guidelines section of the Links area in the right margin. [AUA PSA 2008]
Nov 7. In PSA Screening and Early Detection Part 2 we add: Genetic variations can affect the normal level of PSA even in the absence of prostate cancer. See [PMID: 12865450], [Full Text], [PMID: 12865440], [Full Text], [JNCI press release].
Nov 7. In Radiation risks associated with Prostate Cancer page we add: Bone Scan. The gamma radiation from a bone scan -- this is a test where one is injected with a radionucleotide, a radioactive substance that accumulates in the bone, and a few hours later the patient is scanned with a gamma camera to detect "hot spots". The radiation dose is 4mSv according to information on the National Health System (UK).
Nov 6. In Lycopene, Selenium and Vitamin E in Combination we added: Note that since the information on this page was written a large scale study, the SELECT trial, concluded that selenium and vitamin E do not reduce the risk of prostate cancer (at least in the dosages used). See [SELECT Q&A]. Also a second large scale trial just reported that "individual supplements of 400 IU of vitamin E every other day and 500 mg of vitamin C daily" did not prevent cardiac events (i.e. heart attack, stroke). [PMID: 18997197] [Full Text]
Nov 5. In Advice to the Newly Diagnosed we added: Fig 9 of [this link] shows that the risk of prostate cancer increases as the PCA3 score increases. [PMID: 18295257], [PMID: 18353398] and [PMID: 18801539] conclude, as well, that the (1) higher the PCA3 score the greater the risk of positive biopsy, (2) the higher the likelihood of larger tumor volume and the higher the likelihood of higher Gleason score and (3) the higher the risk of extracapsular extension, respectively. General info on PCA3 can be found [here].
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