Prostate cancer news update, PART B: Tuesday, July 28

Here is Part B of your daily prostate cancer news update. Unless someone announces a cure for prostate cancer we will probably hold any further news until tomorrow!

Topics covered in tihis report include:

  • Is 2.5 ng/mL still an appropriate cut-off for prostate cancer risk?
  • Comparative data on risk of positive surgical margins in men treated with open vs. laparoscopic radical prostatectomy
  • The potential role of somastatin analogs in treatment of androgen-independent prostate cancer

The results of the Prostate Cancer Prevention Trial (PCPT) challenge the recommended PSA thresholds for prostate biopsy (>2.5 ng/mL) because of the 17 percent rate of detection of prostate cancer in men with  PSA levels of 1.1-2.0 ng/mL in that trial. Stephenson et al. have sought to compare the outcome of patients with clincial stage T1c prostate cancer with pretreatment PSA ≤ 2.5 ng/mL as compared to thos with PSA levels of 2.6-4.0 ng/mL. Since 1998, they were able to identify 351 patients with clinical stage T1c and PSA ≤ 4.0 ng/mL treated at the Cleveland Clinic. Of those 351 patients, 84 (24%) had a PSA ≤ 2.5 ng/mL. Patients were treated by radical prostatectomy (RP), brachytherapy, and external-beam radiotherapy (EBRT) in 261 (74 percent), 67 (19 percent), and 23 (7 percent) of cases, respectively. No significant differences between the groups were observed in terms of biopsy-derived (18 vs 22 percent) or pathologic Gleason score 7-8 (44 vs 56 percent), non-organ-confined cancer (11 vs 13 percent), indolent disease (34 vs 24 percent), or 5-year progression-free probability (89 vs 93percent). More biologically unimportant cancers (defined as pathologically organ-confined and Gleason score ≤ 6) were identified among patients with PSA levels ≤ 2.5 ng/mL (55 vs 41 percent), and indolent cancers were three times more frequent than non-organ-confined cancers among these patients. The authors conclude that (at least in their institution) pathologic features and outcome of patients treated at low PSA levels are favorable and similar for patients with PSA ≤ 2.5 vs 2.6-4.0 ng/mL. However, more than 50 percent of the former have potentially biologically unimportant cancer. They state that they “failed to identify a therapeutic benefit to the diagnosis of cancers below the currently accepted PSA thresholds for biopsy.”

Laurila et al. have examined apical and overall margin status following robot-assisted laparoscopic prostatectomy (RALP) as compared open radical retropubic prostatectomy (RRP) in a group of contemporary patients. This was a retrospective review of  98 consecutive RRPs and then 94 RALPs from a single institution. Groups were analyzed and matched with regard to preoperative PSA, cancer grade, pathologic stage, and tumor volume. Surgical margins were quantitated. A higher number of high-risk patients was observed in the RRP vs. the RALP group. To risk-adjust these patient groups, those meeting preoperative high-risk criteria were excluded from further positive margin analysis. (Note: In the view of The “New” Prostate Cancer InfoLink, this exclusion — while statistically necessary — severely impacts the value of the results of this study.) Postoperatively, the average tumor volume was 13 percent in both groups. The frequency of pathologic stage pT3 was similar between RRP patients (14 percent) and RALP patients (11 percent). A positive surgical margin (PSM) was found in 12 cases (14 percent) after RRP and 11 cases (13 percent) after RALP, including apical margins. Positive margins at the apex, non-apex, and both were statistically similar between groups. The authors conclude that, in their institution, no differences were seen between robotic prostatectomy with regard to apical or overall margin status compared with open prostatectomy in lower risk patients.

Schmid et al. have carried out a systematic review of data on the potential role of growth hormone inhibitors in men with hormone-refractory prostate cancer. They note that while androgen ablation has been successful in the treatment of men with advanced prostate cancer to some extent, the vast majority of patients with progressive disease will become androgen independent in time. They suggest that somatostatin (SST) analogs have potential as a therapeutic modality before resorting to chemotherapy or immunotherapy. Forty-two available studies were reviewed and 267 patients with androgen-independent prostate cancer (AIPC) who were treated with SST analogs alone or in combination with other medications (e.g. dexamethasone) were analyzed. Based on their review the authors claim that, “SST analogs were found to be effective, particularly when combined with estrogens or corticosteroids. The side effects are mild and related to the gastrointestinal tract.”

One Response

  1. […] at all on the wires so far. Probably there was so much news yesterday (click here and here). So we thought we’d update you on what The “New” Prostate Cancer InfoLink has […]

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