Detection of prostate cancer with multiparametric MRI (mpMRI): effect of dedicated reader education on accuracy and confidence of index and anterior cancer diagnosis

PURPOSE

To evaluate the impact of dedicated reader education on accuracy/confidence of peripheral zone index cancer and anterior prostate cancer (PCa) diagnosis with mpMRI; secondary aim was to assess the ability of readers to differentiate low-grade cancer (Gleason 6 or below) from high-grade cancer (Gleason 7+).

MATERIALS AND METHODS

Five blinded radiology fellows evaluated 31 total prostate mpMRIs in this IRB-approved, HIPAA-compliant, retrospective study for index lesion detection, confidence in lesion diagnosis (1-5 scale), and Gleason grade (Gleason 6 or lower vs. Gleason 7+). Following a dedicated education program, readers reinterpreted cases after a memory extinction period, blinded to initial reads. Reference standard was established combining whole mount histopathology with mpMRI findings by a board-certified radiologist with 5 years of prostate mpMRI experience.

RESULTS

Index cancer detection: pre-education accuracy 74.2%; post-education accuracy 87.7% (p = 0.003). Confidence in index lesion diagnosis: pre-education 4.22 ± 1.04; post-education 3.75 ± 1.41 (p = 0.0004). Anterior PCa detection: pre-education accuracy 54.3%; post-education accuracy 94.3% (p = 0.001). Confidence in anterior PCa diagnosis: pre-education 3.22 ± 1.54; post-education 4.29 ± 0.83 (p = 0.0003). Gleason score accuracy: pre-education 54.8%; post-education 73.5% (p = 0.0005).

CONCLUSIONS

A dedicated reader education program on PCa detection with mpMRI was associated with a statistically significant increase in diagnostic accuracy of index cancer and anterior cancer detection as well as Gleason grade identification as compared to pre-education values. This was also associated with a significant increase in reader diagnostic confidence. This suggests that substantial interobserver variability in mpMRI interpretation can potentially be reduced with a focus on education and that this can occur over a fellowship training year.

Comparison of Outcomes Between Preoperatively Potent Men Treated with Focal Versus Whole Gland Cryotherapy in a Matched Population

BACKGROUND AND PURPOSE

The refinement in the localization of prostate cancer tumor foci through transperineal template-mapping biopsies and MRI has led to an increased interest in lesion-directed focal prostatic cryoablation. Data are lacking, however, that compare the outcomes of whole-gland (WG) to focal ablation therapy (FT). The aim of our study was to assess both oncologic and functional outcomes between WG and FT cryoablation of the prostate after having matched patients for preoperative characteristics.

PATIENTS AND METHODS

We matched with a 1:1 ratio 317 men who underwent FT with 317 who underwent WG treatment in the Cryo Online Data (COLD) registry between 2007 and 2013. All patients were low-risk according to the D'Amico risk groups and were matched according to age at surgery. We only included preoperatively potent men. Oncologic outcomes were biochemical recurrence (BCR) free-survival defined according to the American Society for Radiation Oncology (ASTRO) and Phoenix criteria and assessed by Kaplan-Meier curves. Only patients with prostate-specific antigen (PSA) nadir data were included in oncologic outcome analysis. Functional outcomes were assessed at 6, 12, and 24 months after the procedure for erectile function (defined as ability to have intercourse with or without erectile aids), urinary continence, urinary retention, and rates of fistula formation.

RESULTS

Median age at the time of the procedure was 66.5 years (standard deviation [SD] 6.6 y), and median follow-up time was 58.3 months. After surgery, 30% (n=95) and 17% (n=55) of the men who received WG and FT, respectively, underwent biopsy, with positive biopsy rates of 11.6% and 14.5%, respectively. BCR-free survival rates at 60 months according to the Phoenix definition were 80.1% and 71.3% in the WG and FT cohorts, respectively, with a hazard ratio of 0.827; according to the ASTRO definition, they were 82.1% and 73%, respectively (all P ≥ 0.1). Erectile function data at 24 months was available for 172 WG and 160 FT treated men. Recovery of erection was achieved in 46.8% and 68.8% of patients in the WG and FT cohorts, respectively (P=0.001). Urinary function data at 24 months was available for 307 WG and 313 FT patients. Continence rates were 98.7% and 100% for WG and FT groups, respectively (P=0.02). Urinary retention at 6, 12, and 24 months was reported in 7.3%, 1.9%, and 0.6%, respectively, in the WG arm, and in 5%, 1.3%, and 0.9%, respectively, in the FT arm. Finally, only one fistula was reported in each group.

CONCLUSIONS

Men with low-risk prostate cancer who underwent FT cryoablation had comparable BCR-survival rates at 60 months to patients treated with WG. However, FT patients had higher erectile function preservation rates at 24 months post-procedure. Urinary continence, retention and fistula rates were similar between the two treatment groups.

Re-purposing cryoablation: a combinatorial 'therapy' for the destruction of tissue

It is now recognized that the tumor microenvironment creates a protective neo-tissue that isolates the tumor from the various defense strategies of the body. Evidence demonstrates that, with successive therapeutic attempts, cancer cells acquire resistance to individual treatment modalities. For example, exposure to cytotoxic drugs results in the survival of approximately 20-30% of the cancer cells as only dividing cells succumb to each toxic exposure. With follow-up treatments, each additional dose results in tumor-associated fibroblasts secreting surface-protective proteins, which enhance cancer cell resistance. Similar outcomes are reported following radiotherapy. These defensive strategies are indicative of evolved capabilities of cancer to assure successful tumor growth through well-established anti-tumor-protective adaptations. As such, successful cancer management requires the activation of multiple cellular 'kill switches' to prevent initiation of diverse protective adaptations. Thermal therapies are unique treatment modalities typically applied as monotherapies (without repetition) thereby denying cancer cells the opportunity to express defensive mutations. Further, the destructive mechanisms of action involved with cryoablation (CA) include both physical and molecular insults resulting in the disruption of multiple defensive strategies that are not cell cycle dependent and adds a damaging structural (physical) element. This review discusses the application and clinical outcomes of CA with an emphasis on the mechanisms of cell death induced by structural, metabolic, vascular and immune processes. The induction of diverse cell death cascades, resulting in the activation of apoptosis and necrosis, allows CA to be characterized as a combinatorial treatment modality. Our understanding of these mechanisms now supports adjunctive therapies that can augment cell death pathways.

Focal therapy: patients, interventions, and outcomes--a report from a consensus meeting

BACKGROUND

Focal therapy as a treatment option for localized prostate cancer (PCa) is an increasingly popular and rapidly evolving field.

OBJECTIVE

To gather expert opinion on patient selection, interventions, and meaningful outcome measures for focal therapy in clinical practice and trial design.

DESIGN, SETTING, AND PARTICIPANTS

Fifteen experts in focal therapy followed a modified two-stage RAND/University of California, Los Angeles (UCLA) Appropriateness Methodology process. All participants independently scored 246 statements prior to rescoring at a face-to-face meeting. The meeting occurred in June 2013 at the Royal Society of Medicine, London, supported by the Wellcome Trust and the UK Department of Health.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Agreement, disagreement, or uncertainty were calculated as the median panel score. Consensus was derived from the interpercentile range adjusted for symmetry level.

RESULTS AND LIMITATIONS

Of 246 statements, 154 (63%) reached consensus. Items of agreement included the following: patients with intermediate risk and patients with unifocal and multifocal PCa are eligible for focal treatment; magnetic resonance imaging-targeted or template-mapping biopsy should be used to plan treatment; planned treatment margins should be 5mm from the known tumor; prostate volume or age should not be a primary determinant of eligibility; foci of indolent cancer can be left untreated when treating the dominant index lesion; histologic outcomes should be defined by targeted biopsy at 1 yr; residual disease in the treated area of ≤3 mm of Gleason 3+3 did not need further treatment; and focal retreatment rates of ≤20% should be considered clinically acceptable but subsequent whole-gland therapy deemed a failure of focal therapy. All statements are expert opinion and therefore constitute level 5 evidence and may not reflect wider clinical consensus.

CONCLUSIONS

The landscape of PCa treatment is rapidly evolving with new treatment technologies. This consensus meeting provides guidance to clinicians on current expert thinking in the field of focal therapy.

PATIENT SUMMARY

In this report we present expert opinion on patient selection, interventions, and meaningful outcomes for clinicians working in focal therapy for prostate cancer.

B-mode and acoustic radiation force impulse (ARFI) imaging of prostate zonal anatomy: comparison with 3T T2-weighted MR imaging

Prostate cancer (PCa) is the most common non-cutaneous malignancy among men in the United States and the second leading cause of cancer-related death. Multi-parametric magnetic resonance imaging (mpMRI) has gained recent popularity to characterize PCa. Acoustic Radiation Force Impulse (ARFI) imaging has the potential to aid PCa diagnosis and management by using tissue stiffness to evaluate prostate zonal anatomy and lesions. MR and B-mode/ARFI in vivo imaging datasets were compared with one another and with gross pathology measurements made immediately after radical prostatectomy. Images were manually segmented in 3D Slicer to delineate the central gland (CG) and prostate capsule, and 3D models were rendered to evaluate zonal anatomy dimensions and volumes. Both imaging modalities showed good correlation between estimated organ volume and gross pathologic weights. Ultrasound and MR total prostate volumes were well correlated (R(2) = 0.77), but B-mode images yielded prostate volumes that were larger (16.82% ± 22.45%) than MR images, due to overestimation of the lateral dimension (18.4% ± 13.9%), with less significant differences in the other dimensions (7.4% ± 17.6%, anterior-to-posterior, and -10.8% ± 13.9%, apex-to-base). ARFI and MR CG volumes were also well correlated (R(2) = 0.85). CG volume differences were attributed to ARFI underestimation of the apex-to-base axis (-28.8% ± 9.4%) and ARFI overestimation of the lateral dimension (21.5% ± 14.3%). B-mode/ARFI imaging yielded prostate volumes and dimensions that were well correlated with MR T2-weighted image (T2WI) estimates, with biases in the lateral dimension due to poor contrast caused by extraprostatic fat. B-mode combined with ARFI imaging is a promising low-cost, portable, real-time modality that can complement mpMRI for PCa diagnosis, treatment planning, and management.

Disparate results between proliferation rates of surgically excised prostate tumors and an in vitro bioassay using sera from a positive randomized controlled trial

In vitro bioassay has been used extensively to test the effects of culturing cancer cells in sera from humans participating in dietary interventions, i.e, studies of modified intake of nutrients for the purpose of reducing cancer risk or progression. It has been hypothesized that cell proliferation rates determined by the in vitro bioassay indicate whether modification of dietary intake could decrease cancer cell growth in vivo. It has been suggested, however, that the in vitro bioassay may not correlate with tumor cell proliferation rates in prostate cancer. We investigated the concordance of cell proliferation rates from surgically excised prostate tumor tissue with the in vitro bioassay using sera from matched patients. We used samples from an earlier randomized clinical trial that showed that supplementation with flaxseed significantly inhibited prostate cancer cell proliferation rates in vivo as indicated by Ki67 staining in tumor specimens. Proliferation rates of LNCaP, DU145 and PC3 cell lines cultured in 10% human sera from participants in the flaxseed trial were determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Spearman's Rho correlation coefficients (ρ) indicated no association between Ki67 staining in prostate tumors and the in vitro bioassay for the three cell lines. These disparate findings suggest that the in vitro bioassay may not provide an accurate assessment of the environment in vivo.

Modernizing the diagnostic and decision-making pathway for prostate cancer

PSA has led to a drastic increase in the detection of prostate cancer, rendering this biomarker the gateway for the diagnostic pathway of prostatic neoplasms. However, the increase in incidence has not been mirrored by a similar reduction in mortality. Widespread PSA testing has facilitated the overdiagnosis and overtreatment of indolent disease. To reduce this phenomenon and avoid negative repercussions on the quality of life of men undergoing unnecessary therapies, the diagnostic pathway of prostate cancer needs to be improved. Multiparametric MRI (mp-MRI) can enhance the sensitivity and specificity of PSA, as well as the shortcomings of random biopsy sampling. This novel imaging technique has been proven to identify larger and more aggressive cancer foci, which should be targeted for treatment. New technological developments now allow for fusion of mp-MRI images with real-time ultrasound, opening the way to lesion-targeted biopsies. Furthermore, mp-MRI and targeted biopsies can also improve active surveillance protocols and permit more conservative focal therapy strategies. By implementing targeted biopsies, the diagnostic pathway will focus on clinically significant disease, consequently reducing overdiagnosis and overtreatment. Before this novel protocol becomes the new gold standard, mp-MRI acquisition and interpretation need to be standardized and targeted-biopsy strategies need to be further validated prior to abandoning random-sampling ones. Several multidisciplinary consortiums are already working on the standardization of prostate MRI, and there are ongoing prospective trials on targeted biopsies and MRI. Soon, imaging of prostatic lesions and selected biopsies will modify the diagnostic evaluation of prostate cancer, reducing overtreatment and therapy-derived complications that negatively affect quality of life.

Metastatic ampullary adenocarcinoma presenting as a hydrocele: a case report

CONTEXT

Metastases from ampullary malignancies are common, but spread to the testicle and paratesticular tissue is exceedingly rare with only 2 reported cases in the literature.

CASE REPORT

We report a case of a 70 year-old male with a history of ampullary adenocarcinoma status post pancreaticoduodenectomy who presented with a symptomatic right-sided hydrocele. Subsequent pathology revealed metastatic ampullary adenocarcinoma.

CONCLUSIONS

Metastasis to the testicle and paratesticular tissue from ampullary malignancies is rare, but must be considered in the evaluation of scrotal masses in patients with a history of ampullary malignancy.

Survival of patients undergoing cytoreductive surgery for metastatic renal cell carcinoma in the targeted-therapy era

BACKGROUND/AIM

In the cytokine era, cytoreductive nephrectomy (CN) improves survival for patients with metastatic renal cell carcinoma (mRCC). We analyzed the effect of CN on the survival of patients diagnosed with mRCC in the era of tyrosine kinase inhibitors (2005-present).

PATIENTS AND METHODS

The Surveillance, Epidemiology, and End Results (SEER) database was used to identify adult patients diagnosed with mRCC between 2005 and 2009. The primary outcome was overall survival, analyzed with multivariable Cox models.

RESULTS

Out of 7,143 incident mRCC cases reported to SEER between 2005-2009, 2,629 (37%) underwent CN. Patients undergoing CN were younger, and more likely to be white, male, and married. Patients with stage T3 tumors were most likely to undergo CN (64%). Patients that underwent CN had improved one-year survival (61% vs. 22%). On multivariable analysis, CN was associated with improved overall survival(hazard ratio[HR]=0.40 95% confidence interval [CI]=0.37-0.43).

CONCLUSION

In the targeted-therapy era, patients with mRCC undergoing CN have improved survival after adjusting for tumor stage and demographic characteristics.

Low central venous pressure versus acute normovolemic hemodilution versus conventional fluid management for reducing blood loss in radical retropubic prostatectomy: a randomized controlled trial

OBJECTIVE

To compare acute normovolemic hemodilution versus low central venous pressure strategy versus conventional fluid management in reducing intraoperative estimated blood loss, hematocrit drop and need for blood transfusion in patients undergoing radical retropubic prostatectomy under general anesthesia.

RESEARCH DESIGN AND METHODS

Patients undergoing radical retropubic prostatectomy under general anesthesia were randomized to conventional fluid management, acute normovolemic hemodilution or low central venous pressure (≤5 mmHg). Treatment effects on estimated blood loss and hematocrit change were tested in multivariable regression models accounting for surgeon, prostate size, and all two-way interactions.

RESULTS

Ninety-two patients completed the study. Estimated blood loss (mean ± SD) was significantly lower with low central venous pressure (706 ± 362 ml) compared to acute normovolemic hemodilution (1103 ± 635 ml) and conventional (1051 ± 714 ml) groups (p = 0.0134). There was no difference between the groups in need for blood transfusion, or hematocrit drop from preoperative values. The multivariate model predicting estimated blood loss showed a significant effect of treatment (p = 0.0028) and prostate size (p = 0.0323), accounting for surgeon (p = 0.0013). In the model predicting hematocrit change, accounting for surgeon difference (p = 0.0037), the treatment effect depended on prostate size (p = 0.0007) with the slope of low central venous pressure differing from the other two groups. Hematocrit was predicted to drop more with increased prostate size in acute normovolemic hemodilution and conventional groups but not with low central venous pressure.

KEY LIMITATIONS

Limitations include the inability to blind providers to group assignment, possible variability between providers in estimation of blood loss, and the relatively small sample size that was not powered to detect differences between the groups in need for blood transfusion.

CONCLUSIONS

Maintaining low central venous pressure reduced estimated blood loss compared to conventional fluid management and acute normovolemic hemodilution in patients undergoing radical retropubic prostatectomy but there was no difference in allogeneic blood transfusion between the groups.

Bilateral focal ablation of prostate tissue using low-energy direct current (LEDC): a preclinical canine study

OBJECTIVE

To evaluate side-effects, erectile function and capability to preserve adjacent tissues of bilateral focal prostate ablation using low-energy direct current (LEDC) in a canine model.

MATERIALS AND METHODS

In all, 12 male Beagle dogs underwent bilateral focal prostate ablation using the NanoKnife™ LEDC system. Three 19 G monopolar electrodes were transperineally placed on each side of the prostate under transrectal ultrasonographic (TRUS) guidance using a triangular probe array. Intra- and postoperative side-effects were recorded. Erectile function was evaluated at baseline and 4-5 and 26-27 days after ablation. The dogs were killed humanely at 7 (six) and 30 days (six) for gross and microscopic evaluation of the prostate and adjacent organs.

RESULTS

The median (range) prostate volume on TRUS was 12.1 (8.9-17.2) mL. The electrodes were placed at a median distance of 0.55-0.66 cm from the capsule, urethra and rectum. All procedures were completed successfully and recovery was uneventful. There were no episodes of urinary retention. All the dogs were able to achieve erections after ablation. Pathological analyses revealed inflammatory changes in the ablation zone at 7 days and replacement by fibrosis at 30 days. On microscopic examination no histological injury to the capsule, urethra, rectal wall or nervous structures was identified.

CONCLUSIONS

In this study, bilateral focal prostate ablation using LEDC was safe and had a favourable side-effects profile limited to transient minor events. LEDC ablation effectively spared adjacent structures as well as physiological functions in all the dogs.