Multiparametric MRI-based 5-year Risk Prediction Model for Biochemical Recurrence of Prostate Cancer after Radical Prostatectomy

Background Current predictive tools to estimate the risk of biochemical recurrence (BCR) after treatment of prostate cancer do not consider multiparametric MRI (mpMRI) information. Purpose To develop a risk prediction tool that considers mpMRI findings to assess the risk of 5-year BCR after radical prostatectomy. Materials and Methods In this retrospective single-center analysis in 1459 patients with prostate cancer who underwent mpMRI before radical prostatectomy (in 2012-2015), the outcome of interest was 5-year BCR (two consecutive prostate-specific antigen [PSA] levels > 0.2 ng/mL [0.2 µg/L]). Patients were randomly divided into training (70%) and test (30%) sets. Kaplan-Meier plots were applied to the training set to estimate survival probabilities. Multivariable Cox regression models were used to test the relationship between BCR and different sets of exploratory variables. The C-index of the final model was calculated for the training and test sets and was compared with European Association of Urology, University of California San Francisco Cancer of the Prostate Risk Assessment, Memorial Sloan-Kettering Cancer Center, and Partin risk tools using the partial likelihood ratio test. Five risk categories were created. Results The median duration of follow-up in the whole cohort was 59 months (IQR, 32-81 months); 376 of 1459 (25.8%) patients had BCR. A multivariable Cox regression model (referred to as PIPEN, and composed of PSA density, International Society of Urological Pathology grade group, Prostate Imaging Reporting and Data System category, European Society of Urogenital Radiology extraprostatic extension score, nodes) fitted to the training data yielded a C-index of 0.74, superior to that of other predictive tools (C-index 0.70 for all models; P ≤ .01) and a median higher C-index on 500 test set replications (C-index, 0.73). Five PIPEN risk categories were identified with 5-year BCR-free survival rates of 92%, 84%, 71%, 56%, and 26% in very low-, low-, intermediate-, high-, and very high-risk patients, respectively (all P < .001). Conclusion A five-item model for predicting the risk of 5-year BCR after radical prostatectomy for prostate cancer was developed and internally verified, and five risk categories were identified. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Aguirre and Ortegón in this issue.

Apparent Diffusion Coefficient and Other Preoperative Magnetic Resonance Imaging Features for the Prediction of Positive Surgical Margins in Prostate Cancer Patients Undergoing Radical Prostatectomy

PURPOSE

To investigate the use of apparent diffusion coefficient (ADC) values and other MRI features for predicting positive surgical margins (PSMs) in patients undergoing radical prostatectomy.

MATERIALS AND METHODS

We retrospectively identified 400 consecutive patients who underwent surgery for prostate cancer between January 2015 and June 2016. ADC values of the index lesion and other preoperative magnetic resonance imaging features, including tumor site, laterality, level, Prostate Imaging Reporting and Data System category, European Society of Urogenital Radiology extracapsular extension score, and prostate volume, were assessed. Univariate and multivariable logistic regression were performed. Performance in predicting the occurrence of PSMs was measured using the area under the curve (AUC). AUC differences were evaluated with the DeLong method. The Youden index was calculated to identify the ADC threshold to best discriminate patients with PSMs.

RESULTS

Of the 400 patients, 105 (26.2%) had PSMs after radical prostatectomy. ADC values, Prostate Imaging Reporting and Data System category, extracapsular extension score, tumor site, and laterality were significantly associated with PSMs (P < .001) in univariate analysis. The AUC of the predictive model based on ADC alone was 68.2% (95% confidence interval, 62.2-74.2%) and did not significantly differ from the best multivariable predictive model which combined laterality, and site with ADC to attain an AUC of 70.0% (95% confidence interval, 64.2-75.8%; DeLong P = .318). The ADC threshold that maximized the Youden index was 960.3 µm²/s.

CONCLUSION

ADC values and preoperative magnetic resonance imaging features can help estimate the risk of PSMs after radical prostatectomy.

In-bore MRI targeted biopsy

Clinical suspicion of Prostate Cancer (PCa) is largely based on increased prostate specific antigen (PSA) level and/or abnormal digital rectal examination (DRE) and/or positive imaging and, up today, biopsy is mandatory to confirm the diagnosis. The old model consisted of Standard Biopsy (SBx), that is random sampling of the prostate gland under ultrasound guidance (TRUS), in subjects with clinical suspicion of PCa. This involves the risk of not diagnosing a high percentage of tumors (up to 30%) and of an incorrect risk stratification. Multiparametric Magnetic Resonance Imaging (mpMRI) has transformed the diagnostic pathway of PCa, not only as an imaging method for detecting suspicious lesions, but also as an intraprocedural guidance for Target Biopsy (MRI-TBx), thus bridging the diagnostic gap. Several single and multicenter randomized trials, such as PROMIS, MRI first, PRECISION and that reported by Van der Leest et al. have confirmed the superiority of the "MRI pathway", consisting of mpMRI and MRI-TBx of suspicious lesions, over the "standard pathway" of SBx in all patients with elevated PSA and/or positive DRE. MRI-TBx appears to be advantageous in reducing the overall number of biopsies performed, as well as in reducing the diagnosis of clinically insignificant disease while maintaining or improving the diagnosis of clinically significant PCa (cs-PCa). Moreover, it shows a reduction in the diagnosis of ins-PCa, and therefore, of overdiagnosis, when using MRI-TBx without sacrificing performance in the diagnosis of cs-PCa.

Perkinsus sp. infecting the oyster Crassostrea rhizophorae from estuaries of the septentrional Northeast, Brazil

Abstract The mangrove oyster Crassostrea rhizophorae is an estuarine resource exploited by riverside communities in Northeast Brazil. Despite its socioeconomic importance, studies on the health status of this bivalve are scanty in this region. The purpose of the present study was to investigate the presence of the protozoan Perkinsus sp. in C. rhizophorae collected in August and September 2011 in three estuaries of the septentrional Northeast, Brazil: Jaguaribe (Ceará), Camurupim (Piauí) and Carnaubeiras (Maranhão) (n= 150 specimens/site). The samples were submitted to Ray’s fluid thioglycollate medium (RFTM), PCR and histology assays. The RFTM assay revealed spherical, blue or bluish-black hypnospores of the genus Perkinsus in 50 specimens (Jaguaribe= 17.3%, Camurupim= 5.3%, Carnaubeiras= 10.6%). The intensity of the infection ranged from very light (1-10 cells per slide) to severe (more than 40 cells in each of 10 fields of the slide) for Jaguaribe; very light for Camurupim and very light to moderate (at least 40 cells observed in each of 10 fields of the slide) for Carnaubeiras. When submitted to confirmatory PCR analysis, 6 cases were confirmed (Jaguaribe=3, Camurupim=1, Carnaubeiras=2). The histology confirmed 21 cases of infection in specimens from the three estuaries. Although local collectors have reported no mortality in oyster populations that might be attributed to infection by Perkinsus, health surveillance of oyster populations in the septentrional region of Northeast Brazil is advisable.

Chromosomes of Gymnothorax funebris and the karyotypical differentiation within Gymnothorax (Anguilliformes: Muraenidae)

Cytogenetic studies in Gymnothorax funebris revealed a diploid chromosome number 2n = 42 (6 metacentrics, 4 submetacentrics, and 32 acrocentrics, FN = 52). The results obtained are novel and similar to those previously described for species belonging to Muraenidae family. The conventional karyotype is also novel and divergent from other species of the genus Gymnothorax, where a higher proportion of metacentric chromosomes predominate. The data are reported and discussed considering the cytotaxonomy of the genus. These results strongly support the current view that chromosomal alterations such as centric fusion and Robertsonian's translocations have an important role in the evolution of this group.

Intraflagellar transport complex in Leishmania spp. In silico genome-wide screening and annotation of gene function

Flagella are constructed and maintained through the highly conserved process of intraflagellar transport (IFT), which is a rapid movement of particles along the axonemal microtubules of cilia/flagella. Particles that are transported by IFT are composed of several protein subunits comprising two complexes (A and B), which are conserved among green algae, nematodes, and vertebrates. To determine whether or not homologues to members of the IFT complex proteins are conserved in Leishmania spp, we scanned genomes, transcriptomes and proteomes of Leishmania species in a search for putative IFT factors, which were then identified in silico, compared, cataloged, and characterized. Since a large proportion of newly identified genes in L. major remain unclassified, with many of these being potentially Leishmania- (or kinetoplastid-) specific, there is a need for detailed analyses of homologs/orthologs that could help us understand the functional assignment of these gene products. We used a combination of integrated bioinformatics tools in a pathogenomics approach to contribute to the annotation of Leishmania genomes, particularly regarding flagellar genes and their roles in pathogenesis. This resulted in the formal in silico identification of eight of these homologs in Leishmania (IFT subunits, 20, 27, 46, 52, 57, 88, 140, and 172), along with others (IFTs 71, 74/72, and 81), as well as sequence comparisons and structural predictions. IFT, an important flagellar pathway in Leishmania, begins to be revealed through screening of trypanosomatid genomes; this information could also be used to better understand fundamental processes in Leishmania, such as motility and pathogenesis.

Population structure of Litopenaeus schmitti (Decapoda: Penaeidae) from the Brazilian coast identified using six polymorphic microsatellite loci

The population structure of the only Litopenaeus species occurring in Brazilian waters, the white shrimp L. schmitti, was surveyed by screening six microsatellite loci. High diversity (HE = 0.863; average number of alleles per locus = 37.8) was found across eight geographical locations (2 degrees S to 27 degrees S). Estimates of overall FST(0.0060) were low but significantly different from zero (P < 0.05). FST pairwise estimates and amova revealed a significant discontinuity around a major biogeographical boundary, near Cabo Frio, at 23 degrees S. This separation may have been caused either by historical or on-going hydrogeographical and/or selective factors.

Molecular phylogeny of western Atlantic Farfantepenaeus and Litopenaeus shrimp based on mitochondrial 16S partial sequences

Partial sequences for the 16S rRNA mitochondrial gene were obtained from 10 penaeid shrimp species: Farfantepenaeus paulensis, F. brasiliensis, F. subtilis, F. duorarum, F. aztecus, Litopenaeus schmitti, L. setiferus, and Xiphopenaeus kroyeri from the western Atlantic and L. vannamei and L. stylirostris from the eastern Pacific. Sequences were also obtained from an undescribed morphotype of pink shrimp (morphotype II) usually identified as F. subtilis. The phylogeny resulting from the 16S partial sequences showed that these species form two well-supported monophyletic clades consistent with the two genera proposed in a recent systematic review of the suborder Dendrobranchiata. This contrasted with conclusions drawn from recent molecular phylogenetic work on penaeid shrimps based on partial sequences of the mitochondrial COI region that failed to support recent revisions of the Dendrobranchiata based on morphological analysis. Consistent differences observed in the sequences for morphotype II, coupled with previous allozyme data, support the conclusion that this is a previously undescribed species of Farfantepenaeus.

[Parathyroid hormone levels in the aged]

PTH is tested in 36 normal subjects over 65 years. A radioimmunoassay is used, which needs a bovine antiserum produced against COOH terminal fragments of the hormone. Serum PTH level results normal in the elderly, and it doesn't show modifications also in the sub-groups, under and over 75 years. No modification is noted respect the sex, too.