Expected impact of MRI-related interreader variability on ProScreen prostate cancer screening trial: a pre-trial validation study.

BACKGROUND: The aim of this study is to investigate the potential impact of prostate magnetic resonance imaging (MRI) -related interreader variability on a population-based randomized prostate cancer screening trial (ProScreen). METHODS: From January 2014 to January 2018, 100 men aged 50-63 years with clinical suspicion of prostate cancer (PCa) in Helsinki University Hospital underwent MRI. Nine radiologists individually reviewed the pseudonymized MRI scans of all 100 men in two ProScreen trial centers. All 100 men were biopsied according to a histological composite variable comprising radical prostatectomy histology (N = 38) or biopsy result within 1 year from the imaging (N = 62). Fleiss' kappa (κ) was used to estimate the combined agreement between all individual radiologists. Sample data were subsequently extrapolated to 1000-men subgroups of the ProScreen cohort. RESULTS: Altogether 89% men of the 100-men sample were diagnosed with PCa within a median of 2.4 years of follow-up. Clinically significant PCa (csPCa) was identified in 76% men. For all PCa, mean sensitivity was 79% (SD ±10%, range 62-96%), and mean specificity 60% (SD ±22%, range 27-82%). For csPCa (Gleason Grade 2-5) MRI was equally sensitive (mean 82%, SD ±9%, range 67-97%) but less specific (mean 47%, SD ±20%, range 21-75%). Interreader agreement for any lesion was fair (κ 0.40) and for PI-RADS 4-5 lesions it was moderate (κ 0.60). Upon extrapolating these data, the average sensitivity and specificity to a screening positive subgroup of 1000 men from ProScreen with a 30% prevalence of csPCa, 639 would be biopsied. Of these, 244 men would be true positive, and 395 false positive. Moreover, 361 men would not be referred to biopsy and among these, 56 csPCas would be missed. The variation among the radiologists was broad as the least sensitive radiologist would have twice as many men biopsied and almost three times more men would undergo unnecessary biopsies. Although the most sensitive radiologist would miss only 2.6% of csPCa (false negatives), the least sensitive radiologist would miss every third. CONCLUSIONS: Interreader agreement was fair to moderate. The role of MRI in the ongoing ProScreen trial is crucial and has a substantial impact on the screening process.

Intra-Abdominal Adhesions Make the Interpretation of Magnetic Resonance Enterography in Crohn's Disease More Difficult.

AIMS: The present study compares preoperative magnetic resonance enterography (MRE) accuracy in diagnosing stenoses, abscesses and fistulas to intraoperative findings in Crohn's disease patients, and determines whether discordance between these methods alter surgical plans. METHODS: Our study included 55 consecutive patients scheduled for elective surgery due to Crohn's disease in a single institution between January 2011 and May 2015, whose surgical findings were also compared to preoperative MREs. Data were retrospectively analyzed. RESULTS: Among these 55 patients, we found 80 stenoses, 5 abscesses and 18 fistulas during surgery. The MRE sensitivity, specificity and accuracy, respectively, reached 100, 77.8 and 96.4% for stenoses; 80.0, 90.0 and 89.1% for abscesses; and 77.8, 83.8 and 81.8% for fistulas. The operative plan was modified for 7 patients (12.7%) due to erroneous MRE diagnoses. No patient needed conversion or an unplanned stoma placement due to an incorrect diagnosis using MRE. The MRE diagnosis did not agree with the surgical findings for 36 lesions, 16 of which resulted from adhesions that explained the incorrect MRE diagnoses. CONCLUSIONS: Hence, while MRE is a useful diagnostic tool preoperatively in Crohn's disease patients, the presence of intra-abdominal adhesions may cause erroneous diagnosis through MRE.

[Imaging of rectal cancer--key to treatment decisions]. / Peräsuolisyövän kuvantaminen--hoitopäätösten avain.

The current guidelines (EURECCA consensus statement 2013) for preoperative imaging of rectal cancer recommend MRI for local staging and CT of the chest, abdomen and pelvis for detection of distant metastases. High resolution MR enables preoperative identification of poor prognostic features. These poor prognostic features are correlated with an increased risk of local recurrence and/or metastatic disease. MRI enables the preoperative multidisciplinary team to decide whether a patient benefits from adjuvant therapy and which surgical technique should be used. A radiological structured report helps clinicians get the most out of the report and increases the number of optimal reports.

[What will determine the first-line treatment of a patient with rectal cancer?]. / Mikä määrää peräsuolisyöpälpotilaan primaarihoidon?

Treatment of a rectal cancer patient is devised by a multidisciplinary expert team. The first thing to be solved is whether a curative treatment, one slowing the progression of the disease, or a symptomatic treatment is aimed at. The extent of the disease is assessed by using whole body CT scan and MR imaging of the rectum. When aiming at curative treatment, the need for preoperative radiation therapy and the surgical technique is assessed on the basis of MRI and clinical examination. The patient's physical condition, associated diseases or pelvic radiotherapy previously applied due to other diseases may restrict the choice of treatment. In an advanced disease, cytostatic chemotherapy is usually the first-line therapy, unless the tumor is obstructing the bowel.

Diffusion-weighted magnetic resonance imaging in prostate cancer patients on active surveillance one year after diagnosis and before repeat biopsy.

OBJECTIVE: The aim of this study was to evaluate prospectively whether diffusion-weighted magnetic resonance imaging (DW-MRI), interpreted in a routine clinical setting, can serve as a diagnostic and prognostic tool for prostate carcinoma patients on active surveillance (AS). MATERIAL AND METHODS: Eighty men enrolled in the Finnish arm of the PRIAS (Prostate Cancer Research International: Active Surveillance) study were followed for at least 1 year and had DW-MRI scans taken in addition to repeat biopsy. Spearman's correlations were analysed between tumour appearance on DW-MRI and clinical variables [age, prostate-specific antigen (PSA), free PSA, PSA doubling time, prostate volume, percentage of cancer at diagnostic biopsy]. The Pearson chi-squared test clarified associations between outcome factors (number of positive cores and Gleason score on repeat biopsy, treatment change) and DW-MRI results. Assumed predictors of deferred radical treatment were examined with logistic regression analysis. Accuracy of tumour localization by DW-MRI compared to repeat biopsy findings was analysed by the chi-squared test. RESULTS: DW-MRI revealed an anatomical lesion suggestive of cancer in 40 patients (50%). MRI positivity showed no significant correlation with clinical variables. No associations existed between tumour appearance on DW-MRI and biopsy findings or discontinuation of AS. The only variable predicting treatment change was higher PSA at discontinuation (p = 0.002). Appearance of tumour, either on T2-weighted MRI (p = 0.273) or on apparent diffusion coefficient maps (p = 0.691), was not a significant predictor of treatment change. CONCLUSIONS: Localized low-grade prostate cancer is challenging to visualize in DW-MRI, and this imaging technique provides no additional prognostic benefit compared to PSA and repeat biopsies.