Tumour Volume of the Index Lesion in Prostate Cancer: Correlation between Results of Multiparametric Magnetic Resonance Imaging and the Histophatology

Abstract

Introduction
Prostate cancer is generally multifocal, presenting a lesion with a dominant focus (index lesion) that is characterized by being the
lesion with the greatest volume and the biological capacity of invasion to adjacent tissues and distant metastases. With the advent
of focal therapy and organ preservation in prostate cancer, it is essential to know the real tumour volume and thus, avoid the per
sistence of disease after treatments with curative intent. The aim of this study is to correlate the results of the dominant tumour
volume obtained from the multiparametric magnetic resonance imaging (MRI) of the prostate and the histopathology.
Material and Methods
A retrospective study was performed which included all radical prostatectomies (RP) with previous MRI. A comparative analysis
was performed between the tumour volume obtained from the MRI and the histopathology.
Results
A total of 46 patients were included in the study. The sensibility of the MRI in diagnosing the index lesion was 82.6%, highlight
ing that all tumours with a Gleason score ≥ 4+3 were diagnosed. The mean tumour volume in the MRI was 14.3 mm and in the
histological result was 18.82 mm (p<0.05). The estimation tumour volume concordance was greatest in higher risk (International
Society of Urological Pathology (ISUP)).
Conclusion
The MRI underestimates the real tumour volume of the prostate cancer index lesion when compared to the histological result of
the surgical piece, being significantly lower in high-risk lesions.