Intravesical suramin in the prevention of transitional cell carcinoma

OBJECTIVES

To examine the effects of intravesical suramin on N-methyl-N-nitrosurea (MNU)-induced bladder tumors in Fischer 344 rats.

METHODS

Multiple cohorts of female rats received four biweekly intravesical instillations of MNU. A control group received no other treatment, the experimental group received 25 mg/kg intravesical suramin twice a week beginning at week 6.

RESULTS

After 18 weeks from the first instillation of MNU, 60% to 65% of control animals developed papillary transitional cell carcinoma, compared with only 0% to 10% of the suramin-treated animals (P = 0.01 to P = 0.0007). There was no local or systemic toxicity observed.

CONCLUSIONS

Intravesical suramin is an effective chemopreventative therapy for transitional cell carcinoma in vivo with minimal toxicity.

Salvage radical prostatectomy: outcome measured by serum prostate specific antigen levels

We reviewed our experience with salvage radical prostatectomy for locally recurrent cancer in 40 patients to assess the current complication rate and the results using prostate specific antigen (PSA) as an indicator of treatment outcome and to identify better criteria for the selection of appropriate candidates for this operation. Most recurrent cancers were detected by digital rectal examination (26 patients) or increasing serum PSA levels (10). The operation was technically challenging, with 6 rectal injuries (15%), 2 requiring temporary colostomy. Serious technical complications were more common (31%) among the 29 patients who underwent pelvic lymphadenectomy at the time of initial radiotherapy than among the 11 treated with external irradiation alone (9%). Urinary incontinence persisted in 18 of 31 evaluable patients (58%) and was successfully corrected with an artificial urinary sphincter in 9. A total of 21 patients (54%) had pathologically advanced disease (seminal vesicle invasion and/or lymph node metastases). Preoperative PSA levels but not clinical stage or biopsy grade correlated with pathological stage (p < 0.03). If the PSA was less than 10 ng./ml. only 15% of the patients had an advanced pathological stage, compared to 86% if the PSA was 10 or more. After 2 to 97 months (mean 39) 2 patients died of metastatic prostatic cancer, 5 had distant metastases and none had symptomatic local recurrence. At 5 years the actuarial nonprogression rate measured by PSA was 55 +/- 20%. The only pretreatment factor predictive of progression was the serum PSA level. If the PSA was less than 10 ng./ml. the actuarial rate of progression was significantly lower than if the PSA was greater than 10 (p < 0.05). The best results were in the subset of 18 patients with cancer confined to the prostate or immediate periprostatic tissue: 82% had no progression at 5 years. Within each of these pathological stages the results of salvage prostatectomy were similar to those for standard radical prostatectomy in patients with no prior irradiation. Although technically challenging, salvage prostatectomy provides excellent control of radio-recurrent cancer confined to the prostate or immediate periprostatic tissue and is best performed before the preoperative PSA level increases to greater than 10 to 20 ng./ml.

Possible mechanism for seeding of tumor during radical prostatectomy

Prostatic adenocarcinoma sometimes recurs locally in the operative bed after radical prostatectomy. Having observed local recurrence in several patients who had a small tumor confined to the prostate on whole mount serial sections, we postulated that some instances of local recurrence could arise from malignant cells shed in prostatic secretions expressed during surgery. To evaluate whether prostatic secretions contain malignant cells and to estimate the frequency of this phenomenon, we collected fresh prostatic secretions from radical prostatectomy specimens immediately after removal. The secretions were analyzed by cytology for the presence of malignant cells. Of 76 samples collected from consecutive patients with clinical stages T1 and T2 prostate cancer at 3 institutions 11 (14%) contained malignant cells. Positive cytology results were most frequent in patients with poorly differentiated tumors. Of 11 cancers with a Gleason sum of 8 to 10 in the prostatectomy specimen 6 (55%) had a positive cytology result. However, of 63 tumors with a Gleason sum of 5 to 7 only 4 (6%) were positive (p < 0.0001). There was no significant correlation with either clinical or pathological stage of the tumor in this small series. Our findings suggest that malignant cells shed during prostatectomy may seed the surgical bed and could be responsible for some instances of local tumor recurrence. The rate of positive cytology results in our study is similar to the local recurrence rates reported in the literature. Surgeons should make prudent attempts to avoid seeding from this source.