Gleason Scores of Localized Prostate Cancer Predict the Risk of Dying From Prostate Cancer
Abstract & Commentary
Synopsis: This study was designed to estimate survival based on competitive risk analyses for men 55-74 years of age who did not receive surgery, external beam radiation, or brachytherapy.
Source: Albertsen PC, et al. JAMA 1998;280:975.
According to albertsen and colleagues, approximately 200,000 men who will be diagnosed with prostate cancer in 1998 will be offered treatments designed to cure or control the progression of their disease. However, the absence of data from large, randomized trials "compromises the ability of these patients and their physicians to assess the relative efficacy of aggressive treatment alternatives compared to more conservative approaches," such as watchful waiting followed by androgen suppression.
This study was designed to estimate survival based on competitive risk analyses for men 55-74 years of age who did not receive surgery, external beam radiation, or brachytherapy. It was a retrospective study of a total of 767 men with localized prostate cancer diagnosed between 1971 and 1984 in Connecticut from files of the Connecticut Tumor Registry. The patients were followed for a period of 10-20 years after diagnosis.
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| Estimates of Dying From Localized Prostate CancerBased on Gleason Scores at Time of Diagnosis* | |
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| *Adapted from JAMA 1998;280:975.
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Men whose prostate biopsy specimens show a Gleason score of 2-4 face a minimal risk of death from prostate cancer within 15 years of diagnoses. Conversely, men whose specimens show a Gleason score of 7-10 face a high risk of death from prostate cancer even when diagnosis is as late as 74 years. Men with Gleason scores of 5 or 6 face a moderate risk of death that increases slowly over at least 15 years of follow-up.
Comment by Ralph R. Hall, MD
This is an interesting and useful study that compares patients from both community and tertiary medical centers. Albertsen et al note that much of our information about prostate cancer is derived from studies at tertiary medical centers that "suffer from known and unknown selection biases that prevent direct comparison" with each other or with our own institutions. I agree with the editorial by Chodak that one of the surprising aspects of this study is the excellent outcome of patients with Gleason scores of 2-4 since many of the patients’ Gleason scores are upgraded to higher Gleason scores when the gland is removed and is subjected to more detailed histological examination.1 It is also apparent that a large number of patients with high Gleason scores died of their disease and that one should consider a more aggressive approach for these patients.
An additional study appearing in the same issue of JAMA comparing the "Biochemical outcome after radical prostatectomy, external beam radiation therapy, or interstitial radiation therapy for clinically localized prostate cancer" may be of value in designing future studies, but their small numbers of moderate- and high-risk patients (based on Gleason scores) invalidates any decision making from these data.2 Their study from tertiary institutions showed "that low-risk patients had estimates of five years PSA outcome after treatment with radical prostatectomy, external beam radiation, or implant radiation with or without neoadjuvant androgen deprivation were not statistically different, whereas intermediate- and high-risk patients treated with radical prostatectomy or external beam radiation did better than those treated with radiation implant therapy. Since the numbers were so small in those patients with Gleason score 8-10 (6 patients), the value of this study must be questioned.
In the study by D’Amico and associates, brachytherapy was carried out with permanent implants. The new temporary implants carry a higher radiation dose and the location of the radioactive seeds is such that there is less exposure to the urethra. This results in more effective therapy with fewer complications—especially urethral obstruction. Studies from Long Beach Memorial Medical Center in California, that will soon be published with a much larger group of patients, will show that brachytherapy is at least as effective as surgery and external beam radiation3 for localized disease.
One of the perplexing issues regarding using biochemical failure (an increasing PSA level) is that, as Chodak notes, "no data exist that correlate the timing of biochemical failure with the more important outcomes of metastases or death." There has been increased enthusiasm for the use of brachytherapy because of the opinion that there are fewer complications with this therapy. However, despite the small numbers in the comparison of the high-risk patients for biochemical failure, the data on brachytherapy should be viewed with skepticism until more data are available. We still do not have the information we need to select the best or no therapy.
References
1 Chodak GW, et al. JAMA 1998;280:1008-1009.
2. D’Amico AV, et al. JAMA 1998;280:969-974.
3. Long Beach Memorial Medical Center. California. Ongoing trial.
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