RADICAL PROSTATECTOMY FOR IMPALPABLE PROSTATE-CANCER - THE JOHNS-HOPKINS EXPERIENCE WITH TUMORS FOUND ON TRANSURETHRAL RESECTION (STAGES T1A AND T1B) AND ON NEEDLE-BIOPSY (STAGE T1C)

We review the pathological findings of impalpable prostate cancer dete cted by transurethral resection (stages T1a and T1b) and needle biopsy (stage T1c). The short-term (4 years) and long-term (8 to 10 years) n atural histories of untreated stage Tla prostate cancer are examined, as are options to follow patients expectantly. The findings on radical prostatectomy for stages T1a and T1b disease are reviewed and compare d. Of the 64 cases of stage T1a disease 13 (20%) showed substantial tu mor, including 7 with more than 1 cc of tumor, 5 with capsular penetra tion and 1 with a Gleason grade 4 + 5 = 9 tumor. Based on preoperative pathological parameters, one could not predict which cases had minima l versus substantial tumor. In a study from our institution that under took complete histological examination of 39 radical prostatectomy spe cimens of stage T1b carcinoma, we found that all prostates contained r esidual carcinoma, 26% had capsular penetration and 10% had invasion o f the seminal vesicles. When comparing morphometrically determined vol umes of carcinoma with similar data from 56 patients with stage T2 car cinoma, stage T1b tumors were much more heterogeneous in grade, locati on and volume than were stage T2 lesions. Unless all 3 variables (grad e, volume and location) were known, the final pathological stage of T1 b cancers could not be predicted with confidence. Finally, we examined preoperative clinical and pathological parameters in 157 men with cli nical stage T1c disease undergoing radical prostatectomy, and correlat ed these findings with pathological extent of disease in the surgical specimen in an attempt to identify a subset of patients with potential ly biologically insignificant tumor who might be followed conservative ly. Of the tumors 16% were insignificant (less than 0.2 cc, organ conf ined and Gleason grade less than 7), 10% were minimal (0.2 to 0.5 cc, organ confined and Gleason grade less than 7), 37% were moderate (more than 0.5 cc or capsular penetration with Gleason sum less than 7) and 37% were advanced (capsular penetration with Gleason sum 7 or more, o r positive margins, positive seminal vesicles or positive lymph nodes) . These findings are intermediate between those found in clinical stag es T1a and T2 disease. The best model predicting insignificant tumor w as a prostate specific antigen (PSA) density of less than 0.1 and no a dverse pathological finding on needle biopsy or a PSA density of 0.1 t o 0.15 with less than 3 mm. low to intermediate grade cancer on only 1 needle biopsy core. The positive predictive value of the model was 95 % with a negative predictive value of 66%. Using this model, we accura tely predicted 73% of cases with insignificant tumor. Although most im palpable prostate cancers diagnosed by needle biopsy are significant t umors that warrant definitive therapy, it may be reasonable to follow some patients whose tumors are most likely insignificant with serial P SA measurements and repeat biopsies.