Prostate cancer news update: Thursday, August 21

Today’s news seems to be light and (with one exception) somewhat technical in nature:

  • Impact of measures of metabolic syndrome and other factors on PSA levels in healthy Korean men
  • A new imaging system that may be able to assist surgeons in ensuring the removal of all cancer tissue
  • A mathematical model for prediction of tumor size based on PSA (and other) data
  • Should brachytherapy be the standard of care for patients with high-risk prostate cancer?

It has long been understood that PSA levels can be impacted by other biological criteria than simply changes in the prostate. Han et al. investigated the correlation between age, body mass index, systolic and diastolic blood pressure (BP), triglycerides, high-density lipoprotein (HDL), and fasting blood glucose (FBG) and the serum PSA level in 38,356 Korean men in an attempt to determine significant factors for predicting the serum PSA level in men with a low risk of prostate cancer. The men were all employees of the Korea Electric Power Corporation who were < 60 years old and had a serum PSA level of < 4 ng/mL, and they were enrolled in this study from January 2002 to December 2006. Their BP, body weight, and body height were measured, and biochemical analyses of FBG, triglycerides, HDL, and serum PSA were performed. Their mean age was 44.38 years; their mean serum PSA level was 0.89 ng/mL; and the incidence of metabolic syndrome was 25.8 percent. On univariate analysis, significant correlations were noted between the serum PSA level and body mass index, diastolic BP, HDL, and FBG (P < .05). Multiple logistic regression analyses using four percentiles (10th, 25th, 75th, and 90th) of the serum PSA level revealed trends for a positive association between older age and diastolic BP and the serum PSA level. The body mass index, HDL, and FBG correlated negatively with the serum PSA level. Han et al. conclude that the serum PSA level is significantly influenced by age and by some components of the metabolic syndrome (obesity, diastolic BP, HDL, and FBG).

According to a report from HealthDay, published in Business Week, a new imaging system may be able to make it easier for surgeons to detect and remove tumors without harming surrounding healthy tissue. The system is called fluorescence-assisted resection and exploration  or FLARE. It includes a near-infrared (NIR) imaging system, a video monitor and a computer, and shows promise for improving surgery for breast, prostate and lung cancers. In advanced stages, the boundaries of these cancers can be difficult to define. FLARE may also help cancer surgeons avoid cutting important structures such as blood vessels and nerves. Patients are injected with special dyes (NIR fluorphores) that target specific structures such as cancer cells. When exposed to NIR light, the dyes light up the cancer cells, which appear on a video monitor. To date the system has only been used to visualize organs and body fluids of mice and map the lymph nodes of pigs. Clinical trials in humans may begin later this year in breast cancer patients.

Also from HealthDay, researchers at Stanford University have developed a mathematical model to use data from blood biomarkers that to help doctors estimate the size of cancer tumors. At present there is no reliable way to use the results of blood-screening tests to gauge potential tumor size. The  researchers developed their model using the PSA and CA125 tests. (The latter is used as a marker for follow-up therapy in ovarian cancer patients.) They found that minimum tumor sizes predicted by their calculations were close to what was actually seen in clinical practice.

Bittner et al. have reviewed available data and concluded that brachytherapy should now be the standard therapy for patients with high-risk prostate cancer. This group of physicians has made this argument before. They are experienced brachytherapists and are clearly publishing what they believe. However, in editorial comment on this article, Nguyen and D’Amico and Kuban both disagree with the manner in which Bittner et al interpret the available data and suggest that their conclusions connot be justified at this time. On the other hand, Blasko, another highly experienced brachytherapist, generally concurs with Bittner et al. The “New” Prostate Cancer InfoLink is of the opinion that this is a case of people seeking to justify their personal beliefs despite the lack of truly compelling data one way or another.

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