68Ga-PSMA PET/CT compared with MRI/CT and diffusion-weighted MRI for primary lymph node staging prior to definitive radiotherapy in prostate cancer: a prospective diagnostic test accuracy study

Lars J. Petersen, Julie B. Nielsen, Niels C. Langkilde, Astrid Petersen, Ali Afshar-Oromieh, Nandita M. De Souza, Katja De Paepe, Rune V. Fisker, Dennis T. Arp, Jesper Carl, Uwe Haberkorn, Helle D. Zacho

    Research output: Contribution to journalArticlepeer-review

    7 Scopus citations

    Abstract

    Background: The aim was to compare the diagnostic accuracy of 68Ga-PSMA PET/CT with conventional cross-sectional imaging and diffusion-weighted MRI (DW-MRI) for detecting lymph node metastasis (LNM) to stage prostate cancer patients. Twenty consecutive, newly- diagnosed prostate cancer patients were prospectively enrolled and underwent 68Ga-PSMA-11 PET/CT, anatomical MRI or contrast-enhanced CT, and DW-MRI prior to laparoscopic, template-based, extended lymph node dissection. Histopathological findings served as the reference test. Results: Histopathology showed LNM in 13 of 20 patients (19 high-risk, 1 intermediate risk). Five patients had metastasis-suspected lymph nodes on 68Ga-PSMA PET/CT. Patient-based analysis showed that the sensitivity and specificity for detecting LNM were 39% and 100% with 68Ga-PSMA PET/CT, 8% and 100% with MRI/CT, and 36% and 83% with DW-MRI, respectively. The positive and negative predictive values were 100% and 49% with 68Ga-PSMA PET/C, 100% and 37% with MRI/CT, and 80% and 42% with DW-MRI. Of 573 dissected lymph nodes, 33 were LNM from 26 regions. True-positive LNM on 68Ga-PSMA PET/CT was 9–11 mm in diameter, whereas false-negative LNM had a median diameter of 4 mm, with only 3 of 30 lymph nodes being larger than 10 mm. LNM were positive for PSMA by immunostaining. Conclusions: The sensitivity of 68Ga-PSMA PET/CT was notably better than that of MRI/CT and comparable to that of DW-MRI. Some false positive findings with DW-MRI reduced its specificity and positive predictive value compared with those of 68Ga-PSMA PET/CT and MRI/CT.

    Original languageEnglish (US)
    Pages (from-to)939-948
    Number of pages10
    JournalWorld journal of urology
    Volume38
    Issue number4
    DOIs
    StatePublished - Apr 1 2020

    Keywords

    • Anatomical cross-sectional imaging
    • Diagnostic accuracy
    • PSMA PET/CT
    • Prostatic neoplasm
    • Staging

    ASJC Scopus subject areas

    • Urology

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