Impact of primary Gleason grade 4 on biochemical recurrence after permanent interstitial brachytherapy in Japanese patients with low- or intermediate-risk prostate cancer

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Background: To reveal a predictive factor for biochemical recurrence (BCR) after permanent prostate brachytherapy (PPB) using iodine-125 (125I) seed implantation in patients with localized prostate cancer classified as low or intermediate risk based on the National Comprehensive Cancer Network (NCCN) guidelines.

Methods: From January 2004 to December 2009, consecutive 418 Japanese patients with clinically localized prostate cancer classified as low or intermediate risk based on the National Comprehensive Cancer Network (NCCN) guidelines were treated by PPB. The clinical factors including pathological data reviewed by central pathologist and follow-up data were prospectively collected. Kaplan-Meier and Cox regression analyses were used to assess the factors associated with BCR.

Results: Median follow-up was 36.0 months. The 2, 3, 4 and 5-year BCR free rates using Phoenix definition were 98.3%, 96.0%, 91.6% and 87.0% respectively. On univariate analysis, primary Gleason grade 4 in biopsy specimen was strong predicting factor (p<0.0001), while Gleason sum, age, initial PSA, initial PSA density, T stage and D90 were insignificant factors. Multivariate analysis indicated that primary Gleason grade 4 was most powerful prognostic factor associated with BCR (hazard ratio=10.101, 95% IC 3.080-33.126, p=0.0001).

Conclusions: The primary Gleason grade 4 carried a worse BCR than the primary grade 3 in Gleason score 7 prostate cancer. Therefore, the indication for PPB in patients with Gleason sum 4+3 should deserve careful and thoughtful consideration.

No significant financial relationships to disclose.

[A comparative study of a thick and standard loop in transurethral resection of the prostate]

We compared the safety and efficacy of transurethral resection of the prostate (TURP) with a thick loop and with a standard loop. We compared 36 consecutive men (median age, 70 years) with symptomatic benign prostatic hyperlasia (BPH) treated by TURP with a thick loop to a cohort of 36 men (median age, 72 years) treated by TURP with a standard loop. The safety parameters of evaluation included the operative time, blood loss, chronological changes in serum sodium, and complications. The efficacy parameters of evaluation included International Prostate Symptom Score, quality of life assessment, peak urinary flow rate, and post-void residual urine volume. The operative time (median, 49.5 versus 43.5 minutes), blood loss (median, 179 versus 127 ml), and change in serum sodium (median, -4.0 versus -6.0 mEq/L) were not significantly greater in the thick loop group than in the standard loop group, respectively. There were no major complications in either group. Clinically significant improvement was observed in all efficacy parameters in both groups, with no difference between the two groups. These results suggest that TURP with a thick loop is not necessarily superior to TURP with a standard loop in terms of decreasing the blood loss and decreasing the operative time.

[Combination chemotherapy with cis-platinum and ifosfamide for hormone unresponsive prostate cancer]

PURPOSE

There is no effective therapy against hormone refractory prostate cancer. This led us to evaluate the effectiveness and toxicity of cis-platinum (CDDP) and ifosfamide (IFM) combination chemotherapy in the patients with hormone-unresponsive carcinoma of the prostate.

METHODS

Patients with hormone-unresponsive prostate cancer were scheduled to receive CDDP 70 mg/m2 intravenously on day 1 and IFM 1.2 g/m2/day intravenously on day 1 through day 5 of 28-day cycle.

RESULTS

Twenty seven patients with hormone unresponsive prostate cancer were enrolled onto this trial. Of these patients, seven (26%) demonstrated a partial objective response (PR), and ten (37%) a stable disease (ST). The response duration of PR cases lasted from 6 to 49 months with a median of 16 months and the response duration of PR + ST cases lasted from 3 to 36 months with a median of 10 months. Subjective improvement was obtained in 11 patients (41%). Survival duration of all cases were 4 to 89 months with a median of 23 months and probabilities of survival at 3 years and 5 years were 36% and 24%, respectively. The toxicity of this treatment was mostly mild to moderate, anemia (96%), leukocytopenia (89%), anorexia (81%), alopecia (67%), thrombocytopenia (44%), hematuria (38%), renal dysfunction (19%) and liver dysfunction (7%) were noticed. Severe toxicity was observed in two cases, one acute renal failure and one endotoxin shock.

CONCLUSION

We conclude that CDDP and IFM combination chemotherapy was active regimen for hormone unresponsive prostate cancer.

Crystal structure of Streptomyces erythraeus trypsin at 2.7 A resolution

The crystal structure of Streptomyces erythraeus trypsin (abbreviated as SET) has been determined in order to clarify the precise structure of the vicinity of the active site of serine protease and to understand its structure-function relationship. Crystals of SET were prepared at its active pH range (pH 5-10) without any inhibitors which might have affected the circumstances around the active sites. The structure model of SET was made based on the electron density map obtained by the multiple isomorphous replacement method at 3.5 A resolution, and refined by the restrained least-squares method. The current model yields a crystallographic R-factor of 0.272 for 4,968 reflections between 8 and 2.7 A resolution. Though the sequence homology among SET, Streptomyces griseus trypsin and bovine trypsin, 32-37%, is not so high, their overall structures are similar to each other. Comparison of the three molecular structures shows that: 1) the folding of the main chains of the three proteins is essentially the same though there are significant differences on the molecular surface; 2) the spatial arrangements of the catalytic triads in the three proteins are similar to each other; 3) in SET and S. griseus trypsin a short stretch of 3(10)-helix is found through Ala56 to Thr59; His57 in this segment is one important amino acid residue involved in the active sites.