Prostate cancer news reports: Sunday, January 10, 2010

Today’s news reports address studies dealing with the following issues:

  • Re-validation of the PCPT-based prostate cancer risk calculator in contemporary patients
  • Can the SPECT/CT-enhanced Prostascint test replace prostate biopsy?
  • Who should be eligible for active surveillance protocols?
  • Predicting survival of hormone-refractory patients progressing after first-line, docetaxel-based chemotherapy

Nguyen et al. have “re-validated” the Prostate Cancer Prevention Trial (PCPT)-based prostate cancer risk calculator sing data from a large, contemporary cohort of patients sampled by extended biopsy schemes (3,482 men who had a total of 4,515 prostate biopsies). It should be remembered that the current prostate cancer risk calculator was developed using data from men enrolled into the PCPT trial between 1993 and 1997.  The results of this re-validation suggest that the current calculator is still “predictive” for prostate cancer risk for men today. However, it does not seem to have the same degree of initial accuracy for contemporary patients diagnosed with today’s extensive biopsy schemes as it did for patients diagnosed 12-15 years ago (when the “sextant” or six-core biopsy was the usual means used to carry out prostate biopsies)

Seo et al. have published data suggesting that the SPECT/CT-enhanced version of the Prostascint test may be able to provide information that could be used to accurately grade prostate cancer in men with clinically localiuzed disease. However, the study does not seem to say that they can accurately distinguish between primary and secondary grades of tumor — let alone identify high tertiary grade tumors. Technical feasibility and clinical utility are not necessarily the same thing at all.

Ploussard et al. have added to the data correlating risk for progression in patients on active surveillance (AS) protocols with pathological outcomes and biochemical recurrence in radical prostatectomy series. Interestingly, while they show clearly that the two out of their three AS protocols that had less restrictive entry criteria have a higher risk for inclusion of men with stage pT3-4 cancers or Gleason 8 disease, they also showed that the 3-year rate of biochemical recurrence-free survival in their three very different AS protocol groups was exactly the same — at 94 percent.

We have separately reported on a paper by Armstrong et al. that defined risk groups for hormone-refractory patients considering docetaxel-based chemotherapy. In a second paper, Armstrong et al. have also attempted to develop methods to project the survival of men who progressed while on or after first-line, docetaxel-based chemotherapy (again based on data from the TAX327 clinical trial).

3 Responses

  1. Re: Ploussard et al. paper …

    Logic is confirmed by the conclusion that, the more liberal the eligibility definition for AS, the higher the likelihood of including more higher risk patients and makes perfect sense.

    The fact that “they also showed that the 3-year rate of biochemical recurrence-free survival in their three very different AS protocol groups, was exactly the same –- at 94 percent” supports the long held contention that MOST prostate cancer progression advances more slowly.

    This also, in my opinion, reflects the relative unreliability of short-term data results in weighing long-term prostate cancer outcomes.

    Re: Seo et al. paper …

    Phantom Definition = “a figment of the imagination”.

    Using 10 men, of which 7 findings reasonably correlated with in vivo results, to suggest that any current imaging can replace biopsy results is EXTREMELY premature, in my opinion. You could ALMOST suggest it is a phantom conclusion!

    -(;-(}) – (aka) az4peaks

  2. John and I tended to disagree on many items many years ago — as time has gone by we seem to be getting to a consensus on some items — like this expressed above.

    Re: the Prostate Cancer Prevention Trial (PCPT)-based prostate cancer risk calculator. Surely the constantly shifting sands of Gleason grading and scores over the last 7 or 8 years (maybe 10 or 12) would have introduced some instability into the outcome?

  3. Terry: I can’t help you with your comment about the calculator. I am just reporting what Mike Kattan and his colleagues found. They’re the experts!

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