[Prostate cancer development after transurethral resection of the prostate--histopathological studies of radical prostatectomy specimens].

PURPOSE: We investigated prostate cancer (ca.) development after transurethral resection of the prostate (TURP).

PATIENTS AND

METHODS

From 1995 to 2003, 430 patients (pts.) received TURP at Toshiba Rinkan Hospital. Of them, 23 pts. (5.3%) had incidental carcinoma (Stage A), which developed into clinically significant ca. after 1 to 5 years in 5 (22% of Stage A, 1.2% of TURP). In 13 (3.2%) of 407 Non-Stage A pts. (who had no ca. initially), prostate ca. developed after 1 to 7 yrs. A total of 21 pts. (including 3 Stage A pts. diagnosed before 1994) underwent radical prostatectomy. Stage A pts. received regular needle biopsy of prostate (Pbx). Non-Stage A pts. were followed by yearly PSA measurement and digital rectal examination (DRE). Detailed histopathological studies were done on 21 radical prostatectomy specimens.

RESULTS

Clinically significant ca. developed in 8 Stage A pts. (all A2) after 1 to 14 yrs. Long term (5 or 10 years) MAB therapy changed moderately-differentiated adenocarcinoma (AC) to poorly-differentiated AC in 2 pts. during follow-up. When ca. developed PSA increased in only 3 of them, DRE was positive just in 1 pt. Tumor invasion was observed mainly in transition zone (TZ), especially anterior to urethra. In spite of no capsular penetration, surgical margin was positive in 2 pts. PSA failure occurred in another 2 pts. Thirteen Non-Stage A pts. showed aggressive ca. (6 moderately-differentiated AC, 6 poorly-differentiated AC, and 1 ductal carcinoma which showed metastasis later), most of which invaded widely in peripheral zone (PZ). Pbx before TURP was done to reveal that there was no cancer in 11 pts. Capsular penetration was seen in 4 pts. Surgical margin was positive in 4 pts. PSA (8.6 +/- 4.0 ng/ml) decreased after TURP but was kept in high level (4.8 +/- 2.2 ng/ml) after 1 year and increased (8.7 +/- 4.5) when cancer was diagnosed in all 13 pts. DRE was positive in 38% of them. Interval between TURP and diagnosis was short in pts. who had cancer of high Gleason Score (GS) or large prostate.

CONCLUSIONS

As significant cancer developed in 22% of Stage A pts. (1.2% of TURP) in long term follow-up, regular Pbx (to get TZ tissue) is mandatory regardless of PSA value or DRE. Aggressive cancer developed in 3.2% of Non-Stage A pts. (3.0% of TURP). Pts. with high PSA or abnormal DRE after TURP must receive needle biopsy actively. Considering that more than 4% of TURP pts. eventually require radical prostatectomy, relatively younger pts. who received TURP have to be carefully followed for a long period.