Preoperative magnetic resonance imaging for detecting uni- and bilateral extraprostatic disease in patients with prostate cancer

Abstract

Objective: The objective of the study was to evaluate the diagnostic accuracy of preoperative magnetic resonance imaging (MRI) for detecting uni- and bilateral extraprostatic disease (T3) in patients with prostate cancer (PCa).

Materials and methods: This prospective study included 199 patients with biopsy-proven PCa who underwent MRI prior to radical prostatectomy from December 2009 to July 2012. Extraprostatic extension and seminal vesicle invasion represented T3 disease, and was classified as uni- (right or left) or bilateral. MRI detection of T3 disease was assessed by descriptive statistics and odds ratio (OR). Whole-mount histopathology was used as the reference standard.

Results: The overall prevalence of pT3 was 105/199 (53 %), unilateral in 81/105 (77 %) and bilateral in 24/105 (23 %). The sensitivity of MRI for predicting pT3 was 76/105 (72 %), specificity 61/94 (65 %), accuracy 137/199 (69 %), and OR 4.8 (95 % CI 2.7-8.8). A complete match with respect to the laterality of pT3 was found in 52/105 (50 %), and the side-specific accuracy was 113/199 (57 %). When unilateral pT3 was found, MRI falsely suggested contralateral T3 in 4/81 (5 %) and bilateral in 8/81 (10 %). When bilateral pT3 was found, MRI falsely suggested unilateral T3 in 12/24 (50 %).

Conclusion: Magnetic resonance imaging (MRI) detected 72 % of all patients with T3 disease, and the accuracy dropped from 69 to 57 % when considering the laterality of T3. Thus far, the MRI technique is not yet adequate to meet the increasing demands of accurate diagnosis of locally advanced disease, and the contemporary MRI staging should be careful.

Trial registration: ClinicalTrials.gov NCT01347320.

Fig. 1

Illustrates the correlation between clinical, radiological, and pathological T classification. In patients with cT1, the sensitivity for predicting T3 disease was 55 %, specificity 70 %, and accuracy 64 %. Moreover, in patients with cT2, the sensitivity was 86 %, specificity 58 %, and accuracy 76 %. cT, rT, and pT: clinical, radiological, and pathological T classification

Fig. 2

A 63-year-old patient with PSA 14.0 ng/mL, cT1c, and biopsy GS 7a. Axial T2-weighted images (a, c, d, f) and axial ADC color overlays (b, e) demonstrate tumors on both sides (green arrowheads). MRI suggested right-sided EPE. Whole-mount histopathology (c, f) verified the existence of both tumors, although pEPE was present on the left side. The surgical margins were negative

Fig. 3

A 62-year-old patient with PSA 5.8 ng/mL, cT2, and biopsy GS 8. Axial T2-weighted image (a) demonstrates a large tumor affecting both lobes, although dominating the right side. Right-sided EPE and bilateral SVI (green arrowheads in c and d) were suggested at MRI, e.g., bilateral T3. Histopathology confirmed right-sided pEPE (b) (blue arrows), although no pSVI was present. The surgical margins were positive on the right side