To Evaluate The Diagnostic Value Of Dynamic Contrast-enhanced MRI For Residual Or Recurrent Prostate Cancer After Cryoablation

ObjectiveConduct a meta-analysis to assess the diagnostic efficiency of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in detection of residual or recurrent prostate cancer after cryotherapy. Use DCE-MRI to discover relapse after cryotherapy as soon as possible. The early detection of prostate cancer is important for salvage treatment and improving patient survival.Materials and methods1. Studies were systematically searched in the PubMed, EMBASE, Cochrane library, SCI, CBM, CNKI, VIP, WanFang, and other databases. Additional studies were manually searched using the references of the retrieved articles. The retrieved deadline time was January1st,2014. Studies were eligible for inclusion based on the inclusion and exclusion criteria, and the qualities of the studies were reviewed based on the QUAD AS criteria. The Meta Disc1.4software was used for meta-analysis, and a summary receiver operating characteristic (SROC) curve was constructed. The pooled weighted estimates of the sensitivity, specificity, diagnostic odds radio, and95%confidence interval were calculated.2. We collected the patients who had been given cryotherapy of localized prostate cancer (T1-3N0M0) and received DCE-MRI examination because of biochemical failure from2006to2012in Tianjin cancer hospital, at the same time get time-signal intensity curve and calculate dynamic enhanced MRI parameters. And the patients underwent prostate biopsy as the reference to check for the DCE-MRI results, with complete follow-up data of medical records. As with other symptoms, it is necessary to make the whole body bone scan, abdominal ultrasound and chest X-ray. If patients without distant metastases, prostate needle biopsy were performed within two weeks after DCE-MRI examination, taking pathologic results as the gold standard to evaluate the performance of DCE-MRI in the diagnosis of prostate cancer local recurrence after cryotherapy. Results1. With the computer search and manual cross-checking of references,274abstracts were retrieved. In the end,14articles (21studies) which fulfilled all of the inclusion criteria were considered for analysis. We divided the21studies into four groups based on the definitive local therapy method (radical prostatectomy, EBRT, HIFU and brachytherapy). Ten studies examining patients after RP had a pooled sensitivity and specificity of87%(95%CI83-91%) and95%(95%CI89-98%), respectively. Six studies examining men after EBRT had a pooled sensitivity and specificity of68%(95%CI61-74%) and88%(95%CI84-90%), respectively. Three studies examining men after HIFU had a pooled sensitivity and specificity of76%(95%CI66-84%) and75%(95%CI69-81%), respectively. One article examining men after high-dose brachytherapy had a sensitivity of50%and a specificity of98%, respectively for DCE-MRI; and a sensitivity of77%and a specificity of93%, respectively for the combined use of T2WI, DWI and DCE-MRI.2. For the types of time-intensity curve, there are27cases appeared as type Ⅰ,15appeared as type Ⅱ and11appeared as type Ⅲ. The TIC curve in10cases of pathologically proven locally recurrence appeared as type Ⅰ in one case, type Ⅱ in two cases and type Ⅲ in seven cases; However, the TIC curve in43cases of pathologically proven recurrence-free appeared as type Ⅰ in26cases, type Ⅱ in13cases and type Ⅲ in4cases. Using standard B to diagnose prostate cancer relapse after cryoablation, that is to say, taking type Ⅲ to diagnose relapse, and type I and type Ⅱ curve to diagnose no relapse. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of dynamic enhanced MRI in the diagnosis of prostate cancer recurrence after cryotherapy were70.0%,90.7%,63.6%,92.8%and86.8%, respectively.3. The median dynamic enhanced MRI parameters of pathologically proven recurrence group:time to peak was7.25min, maximum enhancement ratio was1.895, and early enhancement ratio was1.21; The median dynamic enhanced MRI parameters of pathologically proven recurrence-free group:time to peak was9.15minutes, maximum enhancement ratio was96.8%and early enhancement rate was77.6%. There were statistically significant differences between two groups (P<0.05). Conclusion1. The present evidence suggested that DCE-MRI can accurately detect local recurrence after several definitive local therapies (RP, EBRT, HIFU and brachytherapy) with high sensitivity and specificity. It is of great importance in clinical diagnosis of residual or recurrence of prostate cancer.2. Type of time-intensity curve for prostate cancer recurrence after cryotherapy: type of time-intensity curve for pathologically confirmed recurrence group was most washout type (type Ⅲ); type of time-intensity curve for pathologically confirmed recurrence-free group was most type Ⅰ. With standard B (type Ⅲ as relapse, type Ⅰ and type Ⅱ as no relapse) to diagnose prostate cancer relapse after cryablation, the sensitivity, specificity and accuracy of dynamic enhanced MRI in the diagnosis of prostate cancer recurrence after cryotherapy were70.0%,90.7%and86.8%, respectively. The results confirmed that accuracy of DCE-MRI for diagnosis of prostate cancer recurrence after cryoablation is high, and it is worth of popularization and application in clinic.