Kazuho Suyama

Improved predictability of extracapsular extension and seminal vesicle involvement based on clinical and biopsy findings in prostate cancer in Japanese men

OBJECTIVES The accurate preoperative prediction of the extent of cancer by pathologic examination is essential for choosing the optimal treatment for patients with prostate cancer. Currently available clinical staging methods are not adequate and more precise staging is required. METHODS Using the log likelihood ratio test and receiver operating characteristic (ROC) curve analysis, preoperative variables, including biopsy pathologic findings, were assessed for predicting final pathologic stage in prostate cancer. A multivariate model for predicting disease organ confinement status was established for easy clinical use. RESULTS The use of the number of cores with cancer and maximum cancer length in conjunction with the three variables (prostate-specific antigen, clinical stage, and biopsy Gleason score) was found to significantly improve predictability of extracapsular extension and seminal vesicle involvement in clinically resectable (n = 96) and localized prostate cancers (n = 81) (P < 0.05). Areas under ROC curves for the above two parameter sets (five- versus three-variable model) were 0.8395 and 0.7109, respectively, for capacity for extracapsular extension prediction in clinically localized cancer. These values for seminal vesicle involvement were 0.7861 and 0.6927, respectively. The logistic model gave positive and negative predictive values of 73% and 78%, and 64% and 83%, respectively, for extracapsular extension and seminal vesicle involvement in clinically localized cancer at a predicted probability of 0.5 or greater. CONCLUSIONS The present method may be used to predict non-organ-confined prostate cancer with greater accuracy than the previously reported model using three variables.

Delayed recovery of urinary continence after laparoscopic radical prostatectomy

Aim: To study the rate at which patients regained urinary continence during our institutions early experience with laparoscopic radical prostatectomy.

Limited suppression of prostate-specific antigen after salvage radiotherapy for its isolated elevation after radical prostatectomy

OBJECTIVES To investigate the clinical outcome and degree of prostate-specific antigen (PSA) suppression after salvage radiotherapy performed because of isolated PSA elevation after radical prostatectomy. METHODS We examined the outcomes of 32 patients who underwent radiotherapy after radical prostatectomy. Hypersensitive, as well as conventional, PSA assays were used to measure PSA levels after irradiation. RESULTS Of 125 patients who underwent radical prostatectomy for clinically resectable prostate cancer, 42 (33.6%) developed detectable PSA an average of 13.5 months postoperatively. Thirty-two patients underwent salvage radiotherapy. In 13 patients (40.6%), PSA became undetectable (less than 0.1 ng/mL) at a mean of 1.2 months. Two of these patients later developed detectable PSA within 1 2 months. Of 22 patients who had at least 12 months of follow-up, 8 had a durable PSA response. Of 13 patients who attained an undetectable PSA postoperatively and then showed a delayed progressive increase, 7 exhibited a durable response lasting for more than the 12 months after irradiation. By contrast, only 1 of 9 patients with persistently elevated postoperative PSA showed undetectable levels after irradiation. Frozen sera from the 8 patients with a durable response to irradiation were available to measure levels less than 0.1 ng/mL by hypersensitive assay. The mean value was 0.035 ng/mL at an average of 26.9 months after irradiation. Only 3 patients had levels less than 0.01 ng/mL. CONCLUSIONS Although radiotherapy may be beneficial in a small number of patients, many patients continue to have measurable levels of PSA (more than 0.01 ng/mL) after irradiation. Our results suggest that this treatment in its current form is inadequate to eradicate residual carcinoma.

PROSPECTIVE EVALUATION OF PROSTATE CANCER DETECTION BY PROSTATE SPECIFIC ANTIGEN RELATED PARAMETERS: COMPARISON IN SERUM AND PLASMA SAMPLES

PURPOSE We compared the usefulness of serum and plasma samples for enhancing the specificity of prostate cancer detection. MATERIALS AND METHODS We analyzed receiver operating characteristics curves to evaluate prospectively the cancer detection performance of prostate specific antigen (PSA) related parameters derived from serum and plasma samples in 248 and 249 consecutive patients, respectively. RESULTS Receiver operating characteristics curve analysis showed that PSA density and transition zone PSA density were more powerful predictors of prostate cancer than total or free PSA in the group overall at intermediate serum PSA 2.1 to 10 ng./ml. and in the subgroup with total PSA 4.1 to 10 ng./ml. regardless of digital rectal examination findings. Percent free PSA performed significantly better than total PSA in patients with serum total PSA 4.1 to 10 ng./ml. PSA density, transition zone PSA density and percent free PSA did not differ substantially in patients with serum total PSA 4.1 to 10 ng./ml. However, none of these parameters distinguished patients with prostate cancer from those with benign histology when PSA was in the lower range of 2.1 to 4 ng./ml. The performance of these parameters was worse when plasma sample data were used for calculation. CONCLUSIONS The performance of percent free PSA appears at least comparable to that of PSA density and transition zone PSA density in patients in this cohort with serum total PSA 4.1 to 10 ng./ml. without regard to digital rectal examination. The poor performance of these parameters in the lower PSA range underscores the need for other parameters to improve the specificity of cancer detection in elderly Japanese males. Continued use of serum samples is justified for measuring PSA related parameters by current assay techniques.

Treatment outcome by risk group after radical prostatectomy in Japanese men

North American investigators have suggested the usefulness of risk‐group stratification based on prostate‐specific antigen (PSA), clinical stage and biopsy Gleason score for predicting the biochemical outcome of prostate cancer after radical prostatectomy. There have been no reports of the application of this stratification to early biochemical outcome after radical surgery in Japanese men.

Prospective evaluation of prostate cancer detection by prostate-specific antigen-related parameters

Abstract Background : The diagnostic value of prostate‐specific antigen (PSA) for differentiating prostate cancer from benign prostatic conditions is limited by its lack of specificity. Several PSA‐related parameters have been suggested as enhancing the discriminatory power of total PSA values, but their clinical utility should be considered preliminary until established in a prospectively evaluated cohort.

Decision making using hybrid rough sets and neural networks.

A methodology for using rough sets theory for preference modeling in decision problem is presented in this paper. We will introduce a new method where neural network systems and rough sets theory are completely integrated into a hybrid system and are used cooperatively for decision and classification support. At the first glance, the two methods we discuss have not much in common. But, in spite of the differences between them, it is interesting to try to incorporate both into one combined system, and apply it in the building of a decision support system.

Public Awareness and Knowledge of Prostate Cancer in Japan: Results of a Survey at Short-Stay Examination Facilities

Background:

Impact of biochemical failure on long-term clinical outcome after radical prostatectomy for prostate cancer in Japan

Detailed information is needed to understand the impact of biochemical failure (bF) on long-term outcome after definitive therapy for prostate cancer. In all, 223 consecutive men treated with radical retropubic prostatectomy were followed and long-term clinical outcome was investigated. Pathological examination revealed more locally advanced tumors in this study compared with the typical cohorts seen in the Western series. The Cox proportional hazards model indicates pretreatment prostate-specific antigen levels and risk group stratification to be a significant predictors for bF (P<0.05), but not for overall survival. Seminal vesicle involvement was a significant predictor of systemic progression, cancer death and overall survival (P<0.05). Positive surgical margin and bF were also found to be independent predictors of overall survival (P<0.05). In contrast to reports from Western countries, this study found a significant correlation between bF after radical prostatectomy and overall survival. This may reflect years-later detection of prostate cancer in Japan compared with Western series. Biochemical failure may ultimately be translated into decreased overall survival after sufficient follow-up.

Risk of progression and dying of clinically localized prostate cancer in Japan

SummaryStudy was made of the conservative management of 107 men with clinically localized prostate cancer. Distant metastasis developed more frequently in patients with poorly differentiated tumors than in those with welland moderately differentiated counterparts (P<0.01). Poorly differentiated histology was strongly associated with cancer-specific death (P<0.01). The progression-free and cancer-specific survival of patients with stage T1a disease was significantly better than that of patients with stages T1b, T2a–b, and T2c tumors (P<0.05). Available data clearly demonstrate that prostate cancer is a progressive disease when managed conservatively. Long-term follow-up data indicate the natural history of prostate cancer not to differ significantly according to race, despite noteworthy differences in prevalence and mortality. Patients with localized prostate cancer would be candidates for expectant therapy if they had lower-grade tumors and a life expectancy of 10 years or less. For patients with a 10-year or greater life expectancy and any grade of disease definitive therapy should be applicable.