Prostate cancer news update: Friday, August 21, 2009

In today’s reports we note items related to:

  • Whether add-back estrogen improves cognitive function in men on ADT
  • Exercise and its impact on the side effects of ADT
  • A new technique for delivering prostate cancer “vaccines”
  • The potential of VEGF inhibitors in prostate cancer treatment

Matousek and Sherwin have investigated whether adding back estrogen improves cognitive function in men with more advanced foms of prostate cancer who are being treated with an antiandrogen and a LHRH analog (i.e., combined androgen deprivation therapy or ADT). They conducted a small, randomized, double-blind pilot study in which patients were given either add-back estradiol or a placebo (a sugar pill). There was no evidence from this pilot study that the add-back estradiol had any useful effect on cognition as compared to the placebo.

Culos-Reed et al. have published data from a 16-week evaluation of physical activity as a method for reducing the impact of the side effects of androgen deprivation therapy (ADT) and measurable effects on behavior, quality of life, and fitness. Again, this was a relatively small study, with 53 participants randomized into an intervention group and 47 into a wait-list control group, However, 11 patients dropped out of the intervention group and 23 dropped out of the wait-list control group prior to post-testing. Despite the loss of 34 percent of the patients initially enrolled, the authors report clear evidence that physical activity effectively attenuates many of the side effects of ADT and should be recommended to prostate survivors as a supplement to their drug therapy. What is also clear from this study, however, is that trials like this are difficult to carry out because of the probability of high drop out rates.

Low et al. have reported on a scientifically interesting study in which a new DNA vaccine is injected into prostate cancer patients using a technique known as electoporation. It is far too early to be able to tell whether the use of this technique in combination with this particular vaccine will have a clinical impact on progression of prostate cancer, but it is another example of the ways in which clinical scientists are exploring new treatment opportunities.

Aragon-Ching and Dahut have reviewed the currently available data on a series of “targeted” drug products known as VEGF inhibitors in the treatment of prostate cancer (most specifically the  more advanced forms of the disease). VEGF inhibitors include products like bevacizumab (Avastin), thalidomide (Thalomid), lenalidomide (Revlimid), sunitinib (Sutent), sorafenib (Nexavar), and others. Currently available data suggests that some agents of this type are active in the treatment of advanced forms of prostate cancer, but evidence of a long-term benefit on survival has yet to be established, and all of these agents are associated with risk for significant side effects, which makes their use questionable unless there is a really significant clinical benefit to the patient too.

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