PURPOSEProstate multiparametric magnetic resonance imaging (mpMRI) has utility in detecting post-radiotherapy local recurrence. We conducted a multireader study to evaluate the diagnostic performance of mpMRI for local recurrence after low dose rate (LDR) brachytherapy. METHODSA total of 19 patients with biochemical recurrence after LDR brachytherapy underwent 3T endorectal coil mpMRI with T2-weighted imaging, dynamic contrast-enhanced imaging (DCE) and diffusion-weighted imaging (DWI) with pathologic confirmation. Prospective reads by an experienced prostate radiologist were compared with reads from 4 radiologists of varying experience. Readers identified suspicious lesions and rated each MRI detection parameter. MRI-detected lesions were considered true-positive with ipsilateral pathologic confirmation. Inferences for sensitivity, specificity, positive predictive value (PPV), kappa, and index of specific agreement were made with the use of bootstrap resampling. RESULTSPathologically confirmed recurrence was found in 15 of 19 patients. True positive recurrences identified by mpMRI were frequently located in the transition zone (46.7%) and seminal vesicles (30%). On patient-based analysis, average sensitivity of mpMRI was 88% (standard error [SE], 3.5%). For highly suspicious lesions, specificity of mpMRI was 75% (SE, 16.5%). On lesion-based analysis, the average PPV was 62% (SE, 6.7%) for all lesions and 78.7% (SE, 10.3%) for highly suspicious lesions. The average PPV for lesions invading the seminal vesicles was 88.8% (n=13). The average PPV was 66.6% (SE, 5.8%) for lesions identified with T2-weighted imaging, 64.9% (SE, 7.3%) for DCE, and 70% (SE, 7.3%) for DWI. CONCLUSIONThis series provides evidence that mpMRI after LDR brachytherapy is feasible with a high patient-based cancer detection rate. Radiologists of varying experience demonstrated moderate agreement in detecting recurrence.You may cite this article as: Valle LF, Greer MD, Shih JH, et al. Multiparametric MRI for the detection of local recurrence of prostate cancer in the setting of biochemical recurrence after low dose rate brachytherapy. Diagn Interv Radiol 2018; 24: 46-53.

Background: Breast conservation therapy (BCT) has become an accepted treatment in women with early stage breast cancer due to multiple randomized trials showing equivalent mortality rates when compared to modified radical mastectomy (MRM). Results of the National Cancer Institute's prospective randomized trial comparing MRM to BCT are now reported at a median follow up of 25.4 years. Methods: Between 1979 and 1987, 237 evaluable patients with biopsy proven clinical Stage I or Stage II primary breast cancer were randomized to receive a MRM or a lumpectomy followed by definitive radiation to the entire breast followed by a boost to the tumor bed. An axillary dissection was performed in both arms. Negative margins were not required. Patients with node positive disease in either arm were treated with adriamycin and cytoxan. The primary endpoints were overall survival and disease-free survival. Results: At a median follow-up of 25.4 years, there was no statistical difference in overall survival between either arm, with 45.7% of patients alive in the MRM group and 38.0% alive in the BCT group (p=0.43). Although disease-free survival was significantly worse in patients randomized to BCT (57% vs 82%, P<0.001), the additional treatment failures in the BCT group were primarily isolated ipsilateral breast tumor recurrences (IBTR's) which were salvaged by MRM. 22.3% of BCT patients experienced an IBTR but those patients had no significant decrease in overall survival. There were no differences in distant metastasis between the groups. Clinical factors associated with a worse prognosis include the presence of nodal disease (HR 2.46, 95% CI 1.71-2.71, P<0.05) and tumor size (HR 1.91, 95% CI 1.346-2.711, P<0.05). Conclusion: The 25 year survival rate among women receiving BCT vs MRM in the National Cancer Institute randomized trial appears to be equivalent and is consistent with findings across multiple trials. In patients receiving BCT there is an increased incidence of IBTR's. Despite a higher risk of local failure in the BCT group, there is no increased risk of distant failure or mortality. The risk of local failure however, should be discussed when counseling patients regarding their treatment options. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-10-01.