Prediction of prostate cancer recurrence after radiation therapy using multiparametric magnetic resonance imaging and spectroscopy: assessment of prognostic factors on pretreatment imaging

Abstract

Background: To assess whether data from pre-therapeutic multiparametric magnetic resonance imaging (mpMRI) combined with three-dimensional magnetic resonance spectroscopy (3D MRS) provide prognostic factors of biochemical relapse in patients with localized prostate cancer treated by external radiotherapy or brachytherapy. Methods: In our single institution observational retrospective study we included a cohort of 230 patients treated by external radiotherapy or brachytherapy who had an initial mpMRI with 3D MRS from January 2008 to December 2015 for newly diagnosed localized prostatic cancer, proven histologically. Three trained radiologists recorded tumor characteristics, MRI T-stage and metabolic abnormalities from 3D MRS data. Univariate and multivariate Cox analyzes explored the relationship between clinical and imaging variables to highlight prognostic factors for recurrence, using biochemical relapse as the primary endpoint. Results: mpMRI data analysis allowed to reclassify 21.7% of the patients in a MRI National Comprehensive Cancer Network (NCCN) group higher than their initial clinical T-stage, but also to detect a lesion in 78% of the patients considered as clinically T1c. After a median of follow-up of 8.7 years (IQR, 6.6-10.1) following cancer diagnosis, 36 (16%) patients developed a biochemical relapse. The multivariate Cox analysis demonstrated the existence of 3 independent factors for prediction of biochemical recurrence: extracapsular extension (ECE) (HR =3.33; 95% CI: 1.93-5.73; P<0.01), choline/citrate ratio in healthy tissue in the transition zone (TZ) (HR =2.96; 95% CI: 1.06-8.28; P=0.04) and the NCCN Magnetic Resonance Imaging classification (intermediate versus low-risk, HR =3.06; 95% CI: 1.13-8.30; P<0.01).

Tale of two zones: investigating the clinical outcomes and research gaps in peripheral and transition zone prostate cancer through a systematic review and meta-analysis

“…In a more recent study, Asuscion et al investigated the use of mpMRI (multiparametric MRI) and 3D magnetic resonance spectroscopy to evaluate the prognostic stratification of localised PCa treated by radiotherapy, including external beam with or without brachytherapy. 39 The authors reported biochemical recurrence rates at 5 years of 8% for TZ tumours and 18% for PZ tumours. However, confounding factors of other prognostic factors were not taken into consideration.…”

The prognostic value of zonal origin in clinically localized prostate cancer: a systematic review and meta-analysis

“…Sensitivity analysis was conducted by omitting one study at a time, generating the pooled estimates, and comparing them with the original estimates. Funnel plots, Begg's test, and Egger's test were performed to assess publication bias (19,20). All analysis was performed using STATA/SE 12.0 (STATA, College Station, TX).…”

Emerging Role of Nuclear Medicine in Prostate Cancer: Current State and Future Perspectives

“…Some metabolites such as choline citrate or choline creatine are increased in PC cells [55] and their levels can be evaluated by MR spectroscopy. The multiparametric techniques have been increasingly used in the assessment of prostate malignancy with MR but some issues have emerged with the use of powerful magnets, such as radiofrequency field dis-homogeneity and high local specific absorption rates, that may increase local heating into the body tissues and give rise to safety concerns [56,57]. While T1-weighted images can better describe lymphadenopathy, MR spectroscopy associated with fast T2-weighted imaging is a promising technology for the detection of primary disease [57].…”