RISK OF NON SIGNIFICANT PROSTATE CANCER IN PROSTATE CANCER PATIENTS DIAGNOSED BY AN EXTENDED PROSTATE NEEDLE BIOPSY

PROCEDURE AND TREATED BY RADICAL PROSTATECTOMYA. de la Taille(1), L. Salomon(1), G. Guichard(1), S. Beley(1), H. Faucon(1), Y. Allory(2), R. Yiou(1)

JJ. Patard(3), D. Vordos(1), A. Hoznek(1), C. Abbou(1) Departments of Urology (1) and Pathology (2) - CHU Henri Mondor - Créteil, France

Department of Uorlogy (3) - CHU Pontchaillou - Rennes, France

Extended prostate biopsy protocol is associated with an increased prostate cancer (PC) detection rate. However, the risk of detecting non significant cancer (defined by tumor volume <0.5cc and Gleason score 6) could be also increased. Preoperatively, non significant PC can be suspected when patient has PSA <10ng/ml, T1c, Gleason <6 and one positive biopsy with less than 3mm of cancer on the core. We reviewed our PC patients treated by radical prostatectomy who had these criteria with an extended prostate needle biopsy protocol. Out of 819 patients included in our prospective clinical database of radical prostatectomy, 239 patients were diagnosed by using an extended 21-sample needle biopsy protocol (including sextant biopsies, 3 additional biopsies in each lateral peripheral zone (lateral), 3 biopsies in each transitional zone (TZ) and 3 biopsies in the midline peripheral zone). We selected patients with all criteria of non significant PC and with 1 positive biopsy out of the sextant biopsy (6 biopsies), out of the sextant and lateral biopsies (12 biopsies), out of the sextant, lateral and TZ biopsies (18biopsies) and out of all biopsies (21biopsies). Tumor volume was calculated. Mean age was 62 years, mean serum PSA 6.3ng/ml (2.6-9.9) and prostate volume 61.4cc (34-110). Table shows the number of pT3, Gleason>7 or tumor volume >0.5cc and the number of undiagnosed PC patients (i.e. PC diagnosed on the additional biopsies).

Selection of patients by using preoperative criteria of non significant prostate cancer (T1c, PSA<10, Gleason score <6, 1 positive biopsy out of 21, cancer less than 3mm), underestimates tumor aggressiveness (pT3, Gleason >7 and/or tumor volume>0.5cc) in more than half of the patients. Surprisingly, increasing the selection by the number of total biopsies leads to the same underestimation. These preoperative parameters are not enough to predict a non significant prostate Source of Funding: None

Mondor protocol : 21 biopsies including sextant + 6 PB far lateral + 6 PB in TZ and 3 in median peripheral zone.

Risk of overdiagnosis of non significant prostate cancer ?

Preoperative criteria of non significant prostate cancer- T1c

- PSA < 10ng/ml - Gleason score 6 or less - A single positive biopsy with less than 3mm of cancer

[Terris 2003]

GOAL OF THE STUDY

To assess the risk of non significant prostate cancer on one positive needle prostate biopsy Gleason 6, PSA < 10ng/ml and less than 3 mm of cancer

Abstract

Introduction

Methods

Conclusion

Selection using biopsy parameters (T1c, PSA<10, Gleason=<6, 1 positive biopsy and less than 3mm of cancer) underestimates the risk of non significant prostate cancer

Even with 21 biopsies, more than two third of patients had a significant prostate cancer

819 patients included in our prospective clinical database of radical prostatectomy

239 patients diagnosed by using an extended 21-sample needle biopsy protocol

Mean age: 62 yearsMean serum PSA 6.3ng/ml (2.6-9.9) Prostate volume 61.4cc (34-110)

Evaluation of significant prostate cancer: pT3, Gleason>=7, prostate cancer volume >0.5cc

Results according to the number of biopsies

1+ out of 6 biopsies (sextant) n= 23 patients But: 29 patients were missed by this selection because of

additional positive biopsies

1+ out of 12 PZ biopsies (sextant + far lateral PZ biopsies) n= 24 patients 9 patients were missed by this selection because of

additional positive biopsies

1+ out of 12 PZ biopsies + 6 TZ biopsies n= 24 patients 1 patient was missed by this selection because of

additional positive biopsies)

1+ out of 21 n= 16 patients Mean Gleason score: 6,5 (6 cancer with Gleason 7 and 1

with Gleason 8) Stage: 1 pT0, 3 pT2a, 6 pT2c, 5 pT3a, 1 pT3b

1+ / 6 (n=23)

1+ / 12 (n=24)

1+ / 18 (n=24)

1+ / 21 (n=16)

pT3, Gleason>7 and/or PC volume >0.5cc

12 (52%)

14 (58%)

16 (66%)

7 (44%)

Non diagnosed PC with % of signficiant PC

29 pts with 62%

9 pts with 55%

0 pt

de la Taille A, unpublished data

425 (42.5%)

415 (41.5%)

387 (38.7%)

317 (31.7%)

No. of PCaPatients(%)

Sextant + Lat + TZ +Midline

(21 cores)

Sextant+Lat+TZ

(18 cores)

Sextant+Lat(12 cores)

Sextant(6 cores)

425 (42.5%)

415 (41.5%)

387 (38.7%)

317 (31.7%)

No. of PCaPatients(%)

Sextant + Lat + TZ +Midline

(21 cores)

Sextant+Lat+TZ

(18 cores)

Sextant+Lat(12 cores)

Sextant(6 cores)

1,000 consecutive patients with 21 PB as a first procedure

+ 18%p<0.001

McMenar test

+ 6.7%p<0.02

+ 2%p=0.4

Results

Transrectal ultrasound-guided sextant biopsies (Hodge 1989)Gold standardMinimizing morbidity Detection of clinically insignificant cancerMaximizing the detection of large tumors

However,Sensitivity may be suboptimal, especially for larger and

eccentrically shaped prostatesFalse-negative rates: between 13% to 41% on repeat biopsy

Increasing the number of biopsies?In the transitional zoneModifying the angle of the needle to target the peripheral zone

more efficientlyUse of these approaches = increasing the detection rate from

20.4% to 41%

Tumor Volume>0.5cc

pT3 >0.5ccor Gleason>7

1 / 6(n=23)

10 (43%)

12 (52%)

1 / 12(n=24)

8 (33%)

14 (58%)

1 / 18(n=24)

12 (50%)

16 (66%)

1 / 21(n=16)

5 (33%)

7 (44%)

Significant cancer diagnosed or non diagnosed due to the selection

pT3, Gleason>7 and/or PC volume >0.5cc

Non diagnosed PC with % of signficiant PC

1 / 6(n=23)

12 (52%)

29 ptswith 62%

1 / 12(n=24)

14 (58%)

9 pts with 55%

1 / 18(n=24)

16 (66%)

0 pt

1 / 21(n=16)

7 (44%)

>0.5cc

pT3 >0.5ccor Gleason>7

1 / 6(n=17)

5 (29%)

11 (64%)

1 / 12(n=14)

3 (21%)

7 (50%)

1 / 18(n=15)

3 (20%)

7 (46%)

1 / 24(n=7)

2 (28%)

4 (57%)

Only patients with first positive procedure