Prostate cancer: is inapparent tumor at endorectal MR and MR spectroscopic imaging a favorable prognostic finding in patients who select active surveillance?

Department of Radiology, University of California, San Francisco, CA 94143-0628, USA.

PURPOSE

To retrospectively determine whether inapparent tumor at endorectal magnetic resonance (MR) imaging and MR spectroscopic imaging is a favorable prognostic finding in prostate cancer patients who select active surveillance for management.

MATERIALS AND METHODS

Committee on Human Research approval was obtained and compliance with HIPAA regulations was observed, with waiver of requirement for written consent. 92 men (mean age, 64 years; range, 43-85 years) were retrospectively identified

• who had biopsy-proved prostate cancer,
• who had undergone baseline endorectal MR imaging and MR spectroscopic imaging, and
• who had selected active surveillance for management.

Two readers with 10 and 3 years of experience independently reviewed all MR images and determined whether tumor was apparent on the basis of evaluation of established morphologic and metabolic findings. Another investigator compiled data about baseline clinical stage, biopsy findings, and serum PSA measurements.

Multiple logistic regression analysis was used to investigate the relationship between the clinical parameters and tumor apparency at MR imaging and the biochemical outcome.

RESULTS

1. At baseline MR imaging, readers 1 and 2 considered 54 and 26 patients, respectively, to have inapparent tumor (fair interobserver agreement; kappa = 0.30).
2. During a mean follow-up of 4.8 years, 52 patients had a stable PSA level and 40 had an increasing PSA level.
3. In multivariate analysis, no significant association was found between
   • the baseline clinical stage,
   • [baseline] Gleason score,
   • [baseline] serum PSA level, or
   • the [baseline] presence of apparent tumor at endorectal MR imaging and MR spectroscopic imaging for either reader

   and the biochemical outcome (P > .05 for all).

CONCLUSION

[Baseline] Endorectal MR imaging and MR spectroscopic imaging findings of tumor apparency or inapparency in prostate cancer patients who select active surveillance for management do not appear to be of prognostic value [prognosis being based solely on serial PSA levels increasing slowlier or faster than by a threshold time gradient (also called "PSA velocity") = 0.3 ng/(ml year)].

(c) RSNA, 2008.

PMID: 18430877 [PubMed - indexed for MEDLINE]