The last daily news report of 2008

Today being December 31, this will be the final daily news report of the first calendar year of existence for The “New” Prostate Cancer InfoLink.

There are three reports covered in the news below, the most important of which supports the idea that men with diabetes have a reduced risk for prostate cancer.

Based on a retrospective analysis of information from the Health Professionals Follow-Up Study (HPFUS), Kasper et al. have generated data supporting the hypothesis that a history of diabetes is associated with a reduction in risk for diagnosis of prostate cancer. Between 1986 and 2004, HPFUS identified 4,511 newly diagnosed cases of prostate cancer. While the overall risk for prostate cancer in this cohort of men was about 17 percent lower among those with diabetes (as measured by the hazard ratio or HR), the authors have shown that this risk for prostate cancer had a time-related component. In the first year after diagnosis of (type II) diabetes, there was no reduction in risk for prostate cancer compared to that of men without diabetes (HR = 1.30). In years 1-6 following diagnosis of diabetes, there was a significant reduction in relative risk (HR = 0.82). Then for men 6-15  and > 15 years out after diagnosis of diabetes the risk was still lower, but stable  (HR = 0.75 and 0.78, respectively). Reduced risk for prostate cancer (for obvious reasons) was stronger in the pre-PSA era (i.e., before 1994) as compared to after 1994. The authors also demonstrated that obese and diabetic men had a lower HR for prostate cancer than those who were either not obese and diabetic or obese and non-diabetic. The authors conclude that these results are consistent with the hypothesis that diabetes is associated with reduced risk for prostate cancer. The reason for this reduction in prostate cancer risk among men with diabetes for more than a year is not yet known.

Fujita et al. have used processes known as “principal component analysis” and “maximum-entropy linear discriminant analysis” to try to identify genes with the most discriminative information between normal and tumoral prostatic tissues. Using these sophisticated DNA array-based techniques, they suggest that it was possible to capture the changes in gene dependence networks which are related to cell transformation, and therefore to project that the levels of expression of some genes have greater influence over risk for diagnosis of prostate cancer. However, The “New” Prostate Cancer InfoLink would emphasize that this type of personalized gene expression analysis is nowhere near to ready for clinical application (yet).

Engels et al. have published data demonstrating that prostate cancer radiotherapy in which the patient’s positioning is checked using daily co-registration of X-rays and digitally reconstructed radiographs (image-guided, conformal arc treatment) was in fact more accurate than an older technique in which positioning was done using direct prostate visualization with implanted markers. According to their retrospective analysis of data from 238 patients, “the margins around the clinical target volume appeared to be inadequate in the cases in which markers were used.”

In a separate post we have discussed the publication of a very interesting paper on the ethnography of prostate cancer.

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