Wednesday’s prostate cancer news: February 11, 2009

Today’s news reports contain four key items:

  • A review of the potential of phytochemicals in treatment of prostate cancer
  • A Norwegian study on correlation between biopsy-based and post-surgical Gleason scores
  • A retrospective study on risk for prostate cancer in men being treated with testosterone replacement therapy
  • An announcement of new data on PSP94 in the diagnosis of prostate cancer

Perabo et al. have reviewed the available literature on phytochemicals in the treatment of prostate cancer. Many prostate cancer patients increasingly use such complementary and alternative medicines to support the body’s immune system, to minimize morbidity associated with conventional treatment, to enhance the quality of life, and in the hope to cure prostate cancer when conventional treatment fails. Preclinical in vitro and in vivo data as well as clinical trials with phytosubstances such as genistein, lycopene, epigallocatechin gallate, resveratrol, and mistletoe were assessed. The authors state that (at present)  there is no clinical evidence that phytochemicals have a therapeutic use in prostate cancer in relation to reduction of tumor progression or improved survival. The question about an improved immune function or quality of life remains open. They acknowledge that, “Potentially the use of phytochemicals could play a role in a preventive setting.”

Kvåle et al. have reported on the relationship between the Gleason scores of needle biopsies and radical prostatectomy (RP) specimens in a population-based registry in Norway. Their goal was to clarify whether concordance depends on the annual number of RP specimens assessed in the pathology unit, and to identify preoperative clinical factors that predict upgrading from a Gleason score of ≤ 6 in the biopsy to ≥ 7 in the RP specimen. Based on data from 1,116 patients, the authors showed that the biopsy-based Gleason score under-graded the cancer compared to the post-RP Gleason score in 38 percent of cases. Overgrading occurred in 9 percent of cases, and the two Gleason scores were the same in the remaining 53 percent of cases. Pathology units that examined >40 RP specimens annually had a higher concordance between the Gleason score in the biopsy and RP specimen than did lower-volume units. The rate of upgrading from a Gleason score of ≤ 6 in the biopsy to ≥ 7 in the RP specimen increased with increasing preoperative serum PSA levels, and with increasing intervals between biopsy and RP.

A retrospective review of data from 81 men diagnosed with late-onset hypogonadism (LOH) and treated with testosterone replacement therapy (TRT) has further confirmed that such therapy does not seem to increase the risk for prostate cancer in this population cohort. Coward et al. followed these men for an average time of 33.8 months after starting TRT. All men had a normal PSA level before TRT. Testosterone and PSA levels were assessed every 6-12 months. Patients with a biopsy-confirmed or recent history of prostatitis before treatment were excluded. TRT was discontinued in men who developed prostate cancer. Before and 36 months after treatment the total testosterone levels were 241.1 and 379.8 ng/dl, respectively. Four men (4.9 percent) developed prostate cancer between 22 and 41 months after starting TRT. In men without prostate cancer (95.1 percent), PSA levels did not increase significantly at 1-year intervals for 5 years. Given that LOH is an increasingly prevalent disease characterized by a symptomatically low testosterone level, and TRT is effective in normalizing serum testosterone levels, providing a beneficial cardiovascular effect, and improving sexual function and overall quality of life, the authors conclude that  PSA levels remain stable after normalization of testosterone for ≥ 5 years, that prostate cancer can be effectively diagnosed and treated in men taking TRT, and that the incidence of prostate cancer among men with LOH on TRT is no greater than that in the general population.

Miraculins (a Winnipeg-based medical diagnostics company) has announced that levels of a prostate secretory protein containing 94 amino acids (PSP94) in urine can be used to improve the performance of the free:total PSA ratio in detecting aggressive prostate cancer. The improvement offered by PSP94 is believed to be a novel discovery. According to the company’s media release, standardized PSP94 results combined with the free:total PSA ratio was able to differentiate men with aggressive prostate cancer (Gleason score of 7-10, n = 18) from men with more favorable pathologies (Gleason score ≤ 6, BPH or healthy men, n = 70) with a sensitivity of 94 percent and specificity of 49 percent. (AUC equals 0.80). This result was superior to results given by the free:total PSA ratio alone in the same samples, which had a sensitivity of 94% and specificity of 16%. Hypertenion is a confounding condition affecting the results of testing. When data from men known to have  hypertension were removed from the results, the combination of PSP94 with the free:total PSA ratio gave a sensitivity of 100 percent and a specificity of 84 percent (n = 7 for aggressive cancer and n equals 37 favorable pathologies).It should be noted that Miraculins is not the only company seeking to develop PSP94-based tests for use as diagnostic and prognostic tests associated with prostate cancer.

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