Seventh International Prostate Cancer Congress
July 27 – July 29, 2007
David S. Most, PhD,
Health Information Research, Inc.
North Palm Beach, FL
561 766 6666
This Conference was produced and hosted by the P.E.R., the Physician Educattion Resource group. They plan and produce hundreds of conferences annually in many ofl the specialties and sub-specialties of medicine. The structure of this conference was built around lectures and panel sessions on each of three mornings.
Papers began at 8:00 AM and ran until 1:00 PM including Q&A panels after each group of papers. Typically, 14 to 15 such papers were planned for each morning; a very intense schedule that reduced quality time for useful Q&A
Some 27 of the country’s leading prostate researchers in the fields of urology, radiology, oncology, and microbiology were among the presenters. An interesting observation noted was that only some 10 of the 27 speakers had no “conflicts of interest” to disclose.
All seventeen others reported financial links to one or another or combinations of pharmaceutical companies. They were either consultants to, or on the Speakers Bureaus of, these corporations. The closer the presenter was to anything having to do with drug development, current and/or future, the more conflicts he or she reported.
The urologic surgeons and most of the radiologists reported no conflicts.
The approximately forty five papers that were given ran the gamut from the introduction of a potentially more sensitive and reliable PCa indicator test to replace or supplement PSA, to some of the latest genomics research that is exploring the basic molecular biology of prostate cancer.
Lecturers repeatedly discussed the heterogeneity of PCa as the most logical reason why drugs intended to deal with PCa often have such varied response rates. Typical trial results with new drugs may show that only 15-25% of participants had significantly positive responses while perhaps another 15-25% were only moderate responders.
The balance of the participants may not have responded at all.
Yet all were prostate cancer patients whose disease parameters had been measured and graded using the standard parameters of Gleason Score, PSA, T stage, DRE, etc. Despite being matched by these conventional parameters, wide variations in response to treatment can and do occur.
The heterogeneity of prostate cancer is now being studied via genetic and microbiological approaches and these are likely to be productive approaches. Much more is now known about the “androgen receptor” role on the surface of the cell. Manipulations that affect this AR are being intensively studied.
Second and third line hormonal manipulations are being studied to finesse the issue of androgen independent prostate cancer. Of interest was the discussion of circulating androgens that persist even when testosterone has been reduced to castrate levels.
Despite the advances in knowledge that were discussed, the gap still exists between theory and practice: PSA progression after primary tx is still treated with androgen blockade therapy and the introduction of effective new products is slow.
In the area of new surgical approaches to prostatectomy it was reported by a leading surgeon from Memorial Sloan Kettering that “new” does not necessarily mean “better”.
He is a surgeon who has done thousands of radical prostatectomies using the conventional “open” method and both laparascopic and robotic techniques. The latter two are the least invasive. His conclusion was that the total experience of the surgeon was more important than the method selected.
And this conclusion was offered in spite of the enormous publicity about robotic surgery and its advantages.
He showed data relating number of prior surgeries to five year biochemical failure rates. At least 500 surgeries were required to reach a plateau.
Choose the surgeon, not the method, was his take-away message to the audience.
IMRT is the dominant form of radiotherapy today. Combined with improved methods for imaging the position of the prostate gland prior to irradiation, side effects are being reduced. Use of adjuvant and neo adjuvant hormonal blockade tx in conjunction with IMRT is beginning to show improvements in overall survival rates.
It is worth noting here that rare was the speaker who discussed in any detail the extent of side effects from the various treatment modalities.
Radiation side effects such as rectal injury, incontinence, and impotence were covered in some presentations. Changes in techniques that help reduce these effects were described. Chief among these is the increased use of “gold fiduciaries” implanted into the prostate to allow the technician to determine his target prior to each treatment session.
It was emphasized that a patient planning to undergo external radiation should assure himself that the facility chosen has the most modern equipment installations and will routinely determine the gland’s position prior to each treatment.
Proton beam installations are increasing around the country so we can expect to see more men select that as their primary tx. Because of its unique energy delivery system, proton beam theoretically should have fewer side effects. But, it was emphasized, radiation is still radiation and exposure of non-diseased tissue will still occur.
The trend towards using Docetaxel (DT) as primary chemo for HRPC continues to accelerate. Despite the fact that only a 2+ month improvement in overall survival relative to Mitoxantrone and prednisone, was shown in the clinical trial that led to its approval, it has become the “standard” for chemo tx of advanced PC.
Also, Satraplatin, a new form of platinum based chemo, has been shown to be effective. Recently, however, the FDA has requested additional data for Satraplatin so there is some uncertainty as to the immediate future. Reportedly, it will be back in the market as soon as the FDA’s request for more data has been satisfied.
New drugs continue to be tested as last line tx for HRPC. Atrasentan was mentioned as one. But the data presented during the lectures did not produce any “Aha” moments vis a vis chemo in PC.
In a private communication, a leading oncologist in the NYC region told the writer that this practitioner has pts undergoing 4th and 5th chemo regimens that are prolonging their lives. This Dr. was not reluctant to use chemo drugs that had not yet been approved for PC. Off label applications are limited only by the oncologist’s imagination and willing to experiment with the assistance of the pt.
Take-home message for chemo regimens: DT is the primary chemo drug used today and DT in combination with other drugs are worth exploring. Provided the well known SE’s of chemo can be tolerated by the pt, life can be prolonged even in advanced PC.
ADVANCES IN PROSTATE PATHOLOGY…
Dr. David Bostwick, a world-renowned prostate cancer pathologist, spoke about the newest PC detection test called PCA3. It is based on a urine analysis preceded by prostate massage. It is a test with higher specificity than PSA but does require the services of a urologist to collect the test specimen. It is eleven years since it was first reported and only now is getting used by the physician community.
It is a gene that is highly over-expressed in PC. Bostwick reported that PCA3, when positive, predicted a positive biopsy result in 75% of cases. If a man is scheduled for a PSA test, he should ask his Dr. to have the PSA3 test run. Since it has not yet been FDA approved, Medicare will not pay for it but in our opinion it is worth paying for out of one’s own pocket.
It’s the same old mantra applied to this: THE EARLIER THE DETECTION, THE GREATER THE LIKELYHOOD OF CURE!
He also discussed the use of a triple staining technique by the pathologist to increase the certainty of his/her tissue analysis.
THE ANDROGEN RECEPTOR….
Much talk during the lectures centered on the critical role of the androgen receptors on prostate cells. These are the proteins that accept and admit into the cell, the male hormones that promote PC development and growth. The impact of the androgen receptors is:
-AR activity confers risk for PCa
-AR is essential for PCa in genetically engineered mice
-AR controls PC growth and susceptibility of apoptosis
-AR activity is essential at all stages and phases of PC
(this summary was presented by Prof. E. Gellman, Columbia Univ.)
He referred to the AR as “the oncogene of prostate cancer. It follows therefore that much research is being directed at this target by the pharmaceutical industry. Professor Gellman was identified as a major holder of Genentech and GSK stock.
|7th International Prostate Cancer Congress Part II|
July 2007, reported by David S. Most, Ph.D.
|7th Intl Prostate Congress - Part III|
Trachtenberg,Clinical Trials Review,Klein,
|7th Intl Prostate Congress - Part IV|
Febbo, D'Amico, Sandler, Oh, Roach, Steele
|Remember we are NOT Doctors and have NO medical training.|
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