Five-point Likert scaling on MRI predicts clinically significant prostate carcinoma

BACKGROUND To clarify the relationship between the probability of prostate cancer scaled using a 5-point Likert system and the biological characteristics of corresponding tumor foci. METHODS The present study involved 44 patients undergoing 3.0-Tesla multiparametric MRI before laparoscopic radical prostatectomy. Tracing based on pathological and MRI findings was performed. The relationship between the probability of cancer scaled using the 5-point Likert system and the biological characteristics of corresponding tumor foci was evaluated. RESULTS A total of 102 tumor foci were identified histologically from the 44 specimens. Of the 102 tumors, 55 were assigned a score based on MRI findings (score 1: n = 3; score 2: n = 3; score 3: n = 16; score 4: n = 11 score 5: n = 22), while 47 were not pointed out on MRI. The tracing study revealed that the proportion of >0.5 cm(3) tumors increased according to the upgrade of Likert scores (score 1 or 2: 33%; score 3: 68.8%; score 4 or 5: 90.9%, χ(2) test, p < 0.0001). The proportion with a Gleason score >7 also increased from scale 2 to scale 5 (scale 2: 0%; scale 3: 56.3%; scale 4: 72.7%; 5: 90.9%, χ(2) test, p = 0.0001). On using score 3 or higher as the threshold of cancer detection on MRI, the detection rate markedly improved if the tumor volume exceeded 0.5 cm(3) (<0.2 cm(3): 10.3%; 0.2-0.5 cm(3): 25%; 0.5-1.0 cm(3): 66.7%; 1.0 < cm(3): 92.1%). CONCLUSIONS Each Likert scale favobably reflected the corresponding tumor's volume and Gleason score. Our observations show that "score 3 or higher" could be a useful threshold to predict clinically significant carcinoma when considering treatment options.