UROLOGICAL
ONCOLOGY
Prostate
cancer in a large prostate is associated with a decreased prostate specific
antigen failure rate after brachytherapy
Lehrer S, Stone NN, Stock RG
Department of Radiation Oncology and Urology, Mount Sinai Medical Center,
New York, NY 10029, USA
J Urol. 2005; 173: 79-81
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Purpose:
A large prostate has been found to correlate with improved prostate
cancer survival in men undergoing radical prostatectomy. In the current
study we analyzed the relationship of prostate size and prostate specific
antigen (PSA) failure in men undergoing brachytherapy for localized
prostate cancer.
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Materials and Methods:
We studied data on 613 men who had undergone I radioactive seed implantation.
Average patient age +/- SD was 65 +/- 7.2 years. Average prostate volume
ultrasonically measured at seed insertion was 40 +/- 15 ml. All patients
had a minimum of 2 years of followup.
- Results:
Men with a large prostate had increased freedom from failure
compared to men with a small prostate. Failure time in men with an intermediate
size prostate was between that for large and small prostates. This difference
in failure rates was significant (log rank test p = 0.0002). We further
analyzed our data with Cox regression. Large prostate size significantly
correlated with increased time to PSA failure (p = 0.013) and it was
independent of the significant effects of Gleason score, PSA, disease
stage (p < 0.001), minimal radiation dose covering 90% of prostate
volume (p = 0.008) and hormone treatment, including androgen ablation
(p = 0.001).
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Conclusions:
Some investigators have postulated that paracrine signals acting to
regulate epithelial proliferation in benign prostatic hypertrophy have
beneficial influences on coexistent prostate cancer. Our finding that
the effect of prostate size is independent of Gleason score, PSA and
disease stage supports the paracrine signal mechanism. If a circulating
substance, such as a cytokine, might be responsible for improved survival,
this substance might be useful for treating prostate cancer. Moreover,
since we found that prostate size is independent of PSA, Gleason score
and tumor stage for predicting outcome, we hypothesize that patients
with a small prostate treated with brachytherapy might benefit from
hormone treatment and larger radiation doses. These measures are now
generally reserved for men with more advanced tumors, higher PSA and
increased Gleason scores.
- Editorial
Comment
On first approach the data on the treatment of prostates of different
sizes by brachytherapy are given. In a closer look this paper bears
outcome data of one of the largest cohorts of permanent interstitial
seed (LDR) brachytherapy treated patients with a long term follow up
of 140 months. Therefore, this paper should be read carefully and be
compared to the above cited on.
Again, outcomes for low, intermediate and high-risk patients are given
as PSA-progression-free survival data (defined as 3 consecutive PSA
increases, ASTRO criteria).
In low-risk patients around 95% had no progression after 140 months.
For intermediate risk patients roughly 12% and for high-risk patients
roughly 45% had biochemical progression after 140 months. Interestingly,
the curves do not show any further decrease and remain linear 75 months
after treatment. With these 2 papers in mind, brachytherapy can no longer
be considered an inferior therapeutic option to radical prostatectomy
in men with localized prostate cancer.
Dr.
Andreas Bohle
Professor of Urology
HELIOS Agnes Karll Hospital
Bad Schwartau, Germany |