Serial Magnetic Resonance Imaging in Active Surveillance of Prostate Cancer: Incremental Value - Beyond the Abstract

Current 12-core transrectal biopsy is nonspecific and can miss malignancies (18801515). There is an unmet need for noninvasive monitoring of PCA. mpMRI has been shown to be a significant predictor of biopsy results1.

This study was a retrospective review. 1048 men were screened, and there were 108 men with mpMRI exams 6 months apart, of these 102 were eligible. The final cohort included 49 men. The PSA measurement and prostate value were recorded. Multi parametric MRIs were performed and radiologists were blind to the clinic-pathologic findings. The radiologists were asked to give a suspicious score 1-5 to each of the tumors. 12 site biopsies and target biopsies of suspicious lesions were performed. Progression was indicated by increase in tumor suspicion, doubling of volume, and decrease in lesion ADX of 150 mm2 per second or greater. Any one of these criteria indicates progression.

The 49 patients had a median age of 65 and median PSA of 5ng/ml. 48 index lesions were found. The initial group suspicious ratings of the tumors: 9 were ranked low (2), 26 ranked moderate (3), 11 ranked high (4), and 2 were ranked extremely suspicious (5). For the follow up, 33 had the same index lesion. 19 had been pathologically determined as progressing. 9 were found by targeted biopsy, 7 found by systematic biopsy, and 3 found by both targeted and systematic biopsy. 10 showed mpMRI progression. Of the 10, 7 showed pathological progression. Sensitivity, Specificity, PPV, and NPV of mpMRI were 37%, 90%, 69%, and 70% respectively (AUC .63). Serial mpMRI added to logistic regression (AUC .91).

mpMRI may be a good alternative for noninvasive monitoring. It has low sensitivity and high specificity. Combined serial mpMRI, PSAD, and MCCL are the best option.

Limitations for this study include its retrospective nature. There is also a small sample size, and the inclusion criteria limited the study to men with gleason 6PCA. 

Authors: Ely Felker, Jason Wu, Shyam Natarajan, Daniel Margolis, Steven Raman, Jiaoti Huang, Fred Dorrey, and Leonard Marks

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Reference:

Pinto PA, Chung PH, Rastinehad AR, et al. Magnetic resonance imaging/ultrasound fusion guided prostate biopsy improves cancer detection following transrectal ultrasound biopsy and correlates with multiparametric magnetic resonance imaging. The Journal of urology 2011;186:1281-5.