AUA report and update no. 10: Thursday, April 30, 2009

In a plenary session on Tuesday, Dr. William Aronson summarized current understanding about the impact of diet and lifestyle on prostate cancer development and progression. He was clear that there is still no “level 1” evidence to support nutrition and lifestyle interventions for prevention or treatment of prostate cancer (i.e., no compelling data from large, randomized, controlled clinical trials). Dr. Aronson’s basic “take home” message was that while we know much more than we used to, all we can really tell most patients at present is that:

  • A heart healthy diet is a good idea because cardiac death is the most common cause of death in prostate cancer patients as well as in the population in general.
  • Weight loss is recommended for patients who have an elevated body mass index
  • A diet that includes fat at only 25-35 percent of total caloric intake, decreased red meat consumption, avoidance of simple sugars, and 5+ servings of fruit and vegetables per day is likely to be beneficial
  • Most men could benefit from increased physical activity.
  • Diet and exercise also help to offset the consequences of androgen deprivation therapy.

Alphs et al. (abstract no. 1790) reported on a structured application of empiric antibiotic therapy as a means to determine whether such therapy could help to differentiate between men who really needed a prostate biopsy for risk of prostate cancer and those who did not (because they more probably had only a mild form of prostatitis). They gave antibiotic therapy to 127 consecutive patients (Group A) with a PSA level  > 2.5 ng/ml, a benign prostate examination, and findings negative for bacterial infection. These patients then had a repeat PSA test. A comparison group was comprised of 52 patients (Group B) with similar diagnostic characteristics who were not treated with antibiotics. Of the patients in Group A, complete responders (who had to have had a decrease in their PSA level of > 25 percent after antibiotic therapy) were offered the option to defer a prostate biopsy. All other patients (in Group A and Group B) had a 12-core TRUS-guided biopsy performed.Their results were as follows:

  • Of the complete responders in Group A, 19 continued to defer biopsy and 11 went on to have a biopsy.
  • Of the 11 complete responders in Group A who went on to have a biopsy, 2 were positive for cancer and 4 were positive for high-grade prostatic intraepithelial neoplasia (HG-PIN).
  • Of the partial responders in Group A (36 patients whose PSA dropped but by < 25 percent), 13 were positive for cancer, 4 were positive for HG-PIN, and 1 for atypia.
  • Of the non-responders in Group A (58 patients whose PSA was the same or increased), 27 were positive for prostate cancer and 11 were positive for HG-PIN.
  • Of the patients in Group B (52 patients who never received antibiotic therapy), 17 were positive for prostate cancer, 13 were positive for HG-PIN, and 5 were positive for atypia.

What does this study tell us? Well rightly or wrongly, 19/127 or 15 percent of all patients who had antibiotic therapy were able to avoid a biopsy entirely. This may not seem like a lot, but if you imagine that is 15 percent of all the men who get a prostate biopsy every year in America, that’s a lot of biopsies today — certainly hundreds of thousands. It is also clear that, of the men who did have the antibiotic therapy, there was a notable reduction in the probability of a positive biopsy of any type (2 + 4 = 6/11 or 54 percent) in the men who were complete responders compared to the untreated men (17 + 13 + 5 = 35/52 or 67 percent). And if you look at the data on prostate cancer alone, that comparison is 2/11 = 18 pecent vs. 17/52 =33 percent. The “New” Prostate Cancer InfoLink would like to see this study repeated in a larger, multi-center setting to investigate whethere these data are replicated.

Kim et al. (abstract no. 1788) presented data on Tuesday suggesting that preoperative use of leuprolide acetate may decrease post-operative recovery of potency. The authors compared continence and potency rates in > 1,400 patients who underwent bilateral nerve-sparing prostatectomy with or without preoperative leuprolide therapy. From 1983 to 2008, 1,453 men that underwent radical prostatectomy had pre-operative HT information available. Patients were eligible if they had bilateral nerve-sparing, were potent preoperatively, had no postoperative adjuvant hormone or radiation therapy, and were followed for at least 12 months. Pre-op leuprolide therapy apparently had no impact on post-op continence. However, at 12 months of follow-up, the overall potency rates were 56 percent for the leuprolide-treated group and 63 percent for the control group, respectively.It should be noted that this is not a statistically significant difference in outcomes.

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