Prostate cancer and prostate bed SPECT imaging with prostasint®: Semiquantitative correlation with prostatic biopsy results

D. Bruce Sodee, Rodney J. Ellis, Michael A. Samuels, J. Patrick Spirnak, Wayne F. Poole, Clifford Riester, Dawn M. Martanovic, Robert Stonecipher, Errol M. Bellon

Research output: Contribution to journalArticle

46 Scopus citations

Abstract

BACKGROUND. ProstaScint® (Cytogen Corporation, Princeton, NJ) murine monoclonal antibody imaging is FDA-approved for imaging of prostate cancer patients at high risk for metastatic disease and patients postprostatectomy with a rising serum prostate-specific antigen (PSA) level. ProstaScint® is a murine monoclonal antibody which targets prostate-specific membrane antigen (PSMA). PSMA expression is upregulated in primary and metastatic prostate cancer. FDA Cytogen (Princeton, NJ) protocol studies using 111indium- labeled ProstaScint® revealed correlation between areas of increased concentration in the prostate and biopsy-proven tumors in patients imaged pretherapy. METHODS. In our study, four transverse, single-photon emission tomography (SPECT) images were isolated and regions of interest were selected and correlated with pretherapy prostate biopsy results. Prostate cancer and normal tissue prostate/muscle background (P/M) ratios were derived, so that postprostatectomy/radiation therapy patients could be evaluated for the presence of residual prostate cancer. Twenty-three pretherapy prostate cancer patients with quadrant/sextant biopsies had SPECT 96-hr 111indium ProstaScint® pelvic images. The four transverse 1-cm slices above the midline penile blood pool were chosen, and four to six 27-30-pixel regions of interest were placed over the prostate bed. The background muscle region of interest was placed over the external obturator muscle region. The P/M ratio was calculated and compared to the quadrant/sextant prostatic biopsy result. The same procedure was applied to 17 posttherapy prostate cancer patients with rising PSA. RESULTS. In the 23 pretherapy prostate cancer patients, there was a correlation between the P/M ratio of at least 3.0 in 32 of 35 prostatic cancer biopsy regions, and there was correlation with P/M ratios less than 3.0 in 82 of 89 negative biopsy regions. Seventeen posttherapy patients underwent ProstaScint® studies. Six underwent biopsy, with typically one biopsy site per patient. All 6 had P/M ratios greater than 3.0 in the biopsied region. Five out of six biopsies revealed residual prostate cancer. CONCLUSIONS. A prostate/muscle ratio was developed from 111indium ProstaScint® regions of interest obtained on 1-cm SPECT transverse slices through the prostate bed in 23 patients preprostatic cancer therapy. A P/M ratio above 3.0 correlated in the majority of positive cases, and a P/M ratio below 3.0 was demonstrated in negative prostatic biopsy cases. The P/M ratio of above 3.0 or below 3.0 also separated those posttherapy prostate cancer patients with rising PSA who had residual prostate carcinoma in the prostate bed.

Original languageEnglish (US)
Pages (from-to)140-148
Number of pages9
JournalProstate
Volume37
Issue number3
DOIs
StatePublished - Nov 1 1998
Externally publishedYes

Keywords

  • Interstitial brachytherapy
  • ProstaScint®
  • Prostate cancer
  • Semiquantitative
  • Sextant prostatic biopsy

ASJC Scopus subject areas

  • Urology

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