SEARCH

SEARCH BY CITATION

Keywords:

  • TRUS biopsy;
  • early prostate cancer;
  • cancer detection rate

Abstract

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. CONFLICT OF INTEREST
  8. REFERENCES

OBJECTIVE

To assess the cancer detection rate per individual core biopsy in a 12-core protocol and develop an optimal biopsy regimen for detecting early prostate cancer.

PATIENTS AND METHODS

The study included 445 new patients who had a 12-core transrectal ultrasonography (TRUS)-guided prostatic biopsy over a 40-month period. The 12- core biopsy protocol included parasagittal sextant and six peripheral biopsies. The cancer detection rate per individual core was evaluated to give an optimal biopsy protocol.

RESULTS

Prostate cancer was detected in 142 patients (31.9%). Parasagittal sextant biopsy would have failed to detect 40 (28.2%) of the cancers. Among the various possible biopsy protocols, the optimum 10-core biopsy strategy excluding the parasagittal mid-zone biopsies from the 12-core protocol achieved a cancer detection rate of 98.6%.

CONCLUSION

The cancer detection rate increased from 71.8% for parasagittal sextant biopsies to 88.7% by adding peripheral basal biopsies (8-biopsy protocol); 98.6% of cancers in the series would have been detected with a 10-biopsy strategy omitting the parasagittal mid-zone biopsies. Thus we recommend a 10-core protocol incorporating six peripheral biopsies in patients with elevated age- specific prostate-specific antigen levels (2.6–10.0 ng/mL) for maximising cancer detection.


INTRODUCTION

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. CONFLICT OF INTEREST
  8. REFERENCES

Prostate cancer is the second most common cancer in men, accounting for > 24 000 new cancer cases in the UK in 1999 and nearly 9900 deaths in 2001 [1]. In England and Wales the incidence of prostate cancer in the population has been increasing steadily and has more than doubled in the last two decades [2]. Although screening tests such as a DRE, TRUS and PSA levels help in prostate cancer detection, the lack of specificity and sensitivity confound the diagnosis [3,4]. TRUS-guided systematic prostate biopsy remains the standard test for diagnosing early prostate cancer. The systematic parasagittal sextant biopsy technique has become standard and been shown to outperform directed biopsies [5]. However, even this technique under-diagnoses prostate cancer [6,7]. Protocols using 8–10-core biopsy protocols increases cancer detection rates by 8–15% compared with parasagittal sextant biopsies [6,8].

Eskew et al.[7] reported a 35% increase in cancer detection rate using a protocol of 13–18 TRUS-guided prostate biopsies. They suggested that taking more lateral biopsies was the reason for the increased detection rate. Our recent studies [9,10] confirmed a higher cancer yield from peripheral biopsies than from parasagittal biopsies. Poor sampling of the lateral areas in which many cancers are located could be the reason for a lower cancer detection rate in standard biopsy regimens [11].

The 12-core biopsy protocol was intended to overcome this shortfall with the additional six peripheral biopsies. Although this extended systematic prostate biopsy is used in some centres, the optimum protocol has not been defined. This variance in biopsy protocol may be a result of lack of validation of the most suitable biopsy technique. Thus in the present study we aimed to evaluate the cancer detection rates of both the standard and peripheral core biopsies in a 12-core biopsy protocol, to establish an optimum biopsy strategy.

PATIENTS AND METHODS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. CONFLICT OF INTEREST
  8. REFERENCES

Between January 2000 and April 2003, 445 new consecutive patients (mean age 64.5 years, range 43–84) who were referred to the prostate-assessment clinic with an elevated age-specific PSA level of 2.6–10.0 ng/mL had a systematic 12-core TRUS-guided biopsy. Patients with lesions detected on DRE or TRUS also had the same systematic 12-core protocol in a single outpatient visit. Standard antibiotic prophylaxis of 500 mg ciprofloxacin was given orally to the patient on the morning of the procedure and continued for two further days. For TRUS the Falcon® (Bruel and Kjaer Medical, Denmark) ultrasound machine with a 7.5 MHz transrectal probe was used, which allowed simultaneous scanning in two planes (transverse and sagittal) on the same screen, enabling accurate location of the relevant zones of the prostate. Biopsies were obtained using a disposable 18 G spring-loaded core biopsy needle, according to a standard protocol by an experienced urologist. The 12-core biopsy technique incorporates six laterally targeted biopsies in addition to the conventional parasagittal sextant biopsies. The peripheral biopsies were obtained by directing the needle just medial to the lateral edge of the prostate for cores A–F and from the base, mid-zone and apices. Biopsy core specimens were placed in separate containers of 10% neutral buffered formalin and designated as either right or left apical, mid-zone or basal peripheral or para-sagittal biopsy cores (Fig. 1). Before sampling, 10–20 mL of 1% lignocaine was infiltrated into the periprostatic tissue on the right and left base for pain control; the procedure was well tolerated. Individual cores were analysed histopathologically.

image

Figure 1. Prostate and seminal vesicles showing core biopsy sites in a 12-core biopsy protocol. Key: A, right base periphery; B, right mid-zone periphery; C, right apex periphery; D, left base periphery; E, left mid-zone periphery; F, left apex periphery; G, right base; H, right mid-zone; I, right apex; J, left base; K, left mid-zone; L, left apex.

Download figure to PowerPoint

RESULTS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. CONFLICT OF INTEREST
  8. REFERENCES

Cancer was detected in 142 patients (31.9%); men with cancer were older (mean 65.6 vs 64.0 years) and had a higher median PSA level (7.1 vs 6.3 ng/mL). Of the 142 cancers diagnosed, peripheral biopsies were positive in 124 and para-sagittal biopsies in 102. Among the 12 cores the maximum diagnostic yield was from the basal and mid-zone peripheral biopsies (36.3%) (Fig. 2). The mean yield per peripheral biopsy was consistently higher than the parasagittal biopsies (35.9% vs 27.8%); 40 cancers (22.9%) were detected only from peripheral biopsies and would have been missed by parasagittal sextant biopsies. Furthermore, all but five of these cancers were positive in peripheral basal or apical biopsies. Interestingly, 18 cancers were diagnosed only in parasagittal biopsies.

image

Figure 2. Cancer detection rate per individual core.

Download figure to PowerPoint

The detection rates for each potential biopsy regimen that combined 8- or 10-core protocols are shown in Fig. 3. Analysis of individual cores showed the best 8-core biopsy protocol included biopsies from the peripheral basal region and the parasagittal sextant regimen, detecting 88.7% of the cancers; 98.6% of the cancers would have been detected by a 10-core biopsy, excluding parasagittal mid-zone biopsies from the 12-core protocol.

image

Figure 3. a, Optimum 8-core protocol detecting 88.7% of cancers; and b, optimum 10-core protocol detecting 98.6% of cancers.

Download figure to PowerPoint

DISCUSSION

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. CONFLICT OF INTEREST
  8. REFERENCES

The detection of prostate cancer depends on histological analysis of tissue samples obtained from core biopsies. Numerous studies have indicated that taking more cores will increase the cancer detection rate [6,7,12–17]. It is still unclear whether the higher cancer detection rate is a reflection of wider sampling or taking more cores. Most agree that parasagittal sextant biopsies per se are inadequate in prostatic biopsy protocols. In the present study parasagittal sextant biopsies missed 28.2% of the cancers. Investigators have attempted to modify this suboptimal prostate sampling technique either by increasing the number of cores [13,17] or by multizonal sampling. Eskew et al.[7] reported better detection rates with a systematic five-region biopsy method than with the standard sextant biopsy.

In the present study we examined the efficacy of the ‘single-visit’ 12-core biopsy protocol for detecting early prostate cancer. We attempted to address the findings by using systematic 12-core region-directed biopsies, which included six cores directed peripherally. Individual core-based analysis showed the highest cancer detection rate from the peripheral apex and base. The surprisingly high detection rate from lateral biopsies than from standard biopsies emphasizes the importance of sampling cores from these regions. This is probably because most cancers originate peripherally [16]. We suspect that the broad base is under-sampled by just two parasagittal basal biopsies, explaining the high cancer detection rate with peripheral basal biopsies.

We assessed different permutations and combinations to suggest an optimum core biopsy protocol. A 10-core biopsy protocol excluding the peripheral mid-zones would detect 96.5% of the cancers. However, 98.6% of cancers would be detected if a 10-core cost-effective strategy excluding the parasagittal mid-zone biopsies was used.

In conclusion, the cancer detection rate increased from 71.8% for parasagittal sextant biopsies to 88.7% by adding peripheral basal biopsies (8-biopsy protocol); 98.6% of cancers in this series would have been detected with an effective 10-biopsy strategy omitting the parasagittal mid-zone biopsies. We suggest an optimum 10-core strategy incorporating at least six peripheral biopsies in patients with an age-specific PSA level of 2.6–10.0 ng/mL.

REFERENCES

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. CONFLICT OF INTEREST
  8. REFERENCES
  • 1
    Cancer research UK. ‘Statistics – prostate cancer’ Last updated 18072003. At http://cancerresearchuk.org/ aboutcancer/statistics/prostatecancer. Accessed 20/07/2003
  • 2
    Foster CS, Cornford P, Forsyth L, Djamgoz MBA, Ke Y. The cellular and molecular basis of prostate cancer. BJU Int 1999; 83: 17194
  • 3
    Vo T, Riftkin MD, Peters TL. Should ultrasound criteria of the prostate be redefined to better evaluate when and where to biopsy. Ultrasound Q 2001; 17: 1716
  • 4
    Clements R. The role of transrectal ultrasound in diagnosing prostate cancer. Curr Urol Report 2002; 3: 194200
  • 5
    Hodge KK, McNeil JE, Terris MK, Stamey TA. Random systematic versus directed ultrasound guided transrectal core biopsies of the prostate. J Urol 1989; 142: 715
  • 6
    Norberg M, Egevad L, Holmberg L, Sparen P, Norlen BJ, Busch C. The sextant protocol for ultrasound-guided core biopsy cores of the prostate under-estimates the presence of cancer. Urology 1997; 50: 5626
  • 7
    Eskew LA, Bare RL, McCullough DL. Systematic 5 region prostate biopsy is superior to sextant method for diagnosing carcinoma of the prostate. J Urol 1997; 157: 199203
  • 8
    Garber SJ, Goldenberg SL, Cooperberg PL, Wong AD, Bilby JH, Mathieson JR. Systematic transrectal ultrasound- guided biopsy of the prostate. Can Assoc Rad J 1994; 45: 38790
  • 9
    Philip J, DeSouza J, Hough C, Javlé P. Role of peripheral basal biopsies in prostate cancer detection. BJU Int 2003; 91 (Suppl 2): 49
  • 10
    Philip J, Hough C, DeSouza J, Javlé P. Importance of peripheral basal biopsies in maximising prostate cancer detection in 8, 10 or 12 core biopsy regimes. Eur Urol 2003; 2 (Suppl 1): 108
  • 11
    McNeal JE. Origin and development of carcinoma in the prostate. Cancer 1969; 23: 2434
  • 12
    Naughton CK, Smith DS, Humphrey PA, Catalona WJ, Keetch DW. Clinical and pathologic tumour characteristics of prostate cancer as a function of the number of biopsy cores: a retrospective study. Urology 1998; 52: 80813
  • 13
    Levine MA, Ittman M, Melamed J, Lepor H. Two consecutive sets of transrectal ultrasound guided sextant biopsies of the prostate for the detection of prostate cancer. J Urol 1998; 159: 4715
  • 14
    Chang JJ, Shinohara K, Bhargava V, Presti JC Jr. Prospective evaluation of lateral biopsy cores of the peripheral zone for prostate cancer detection. J Urol 1998; 160: 21114
  • 15
    Ravery V, Goldblatt L, Royer B, Blanc E, Toublanc M, Boccon-Gibod L. Extensive biopsy protocol improves the detection rate of prostate cancer. J Urol 2000; 164: 3936
  • 16
    Presti JC Jr, Chang JJ, Bhargava V, Shinohara K. The optimal systematic prostate biopsy scheme should include 8 rather than 6 biopsy cores. Results of a prospective clinical trial. J Urol 2000; 163: 1637
  • 17
    Presti JC Jr, O'Dowd GJ, Miller MC, Mattu R, Veltri RW. Extended peripheral biopsy scheme increase cancer detection rates and minimize variance in prostate specific antigen and age related cancer rates: Results of a community multi-practice study. J Urol 2003; 169: 1259