Lymph node ratio determines the benefit of adjuvant radiotherapy in pathologically 3 or less lymph node-positive prostate cancer after radical prostatectomy: a population-based analysis with propensity-score matching

Semiautomated pelvic lymph node treatment response evaluation for patients with advanced prostate cancer: based on MET-RADS-P guidelines

BACKGROUND

The evaluation of treatment response according to METastasis Reporting and Data System for Prostate Cancer (MET-RADS-P) criteria is an important but time-consuming task for patients with advanced prostate cancer (APC). A deep learning-based algorithm has the potential to assist with this assessment.

OBJECTIVE

To develop and evaluate a deep learning-based algorithm for semiautomated treatment response assessment of pelvic lymph nodes.

METHODS

A total of 162 patients who had undergone at least two scans for follow-up assessment after APC metastasis treatment were enrolled. A previously reported deep learning model was used to perform automated segmentation of pelvic lymph nodes. The performance of the deep learning algorithm was evaluated using the Dice similarity coefficient (DSC) and volumetric similarity (VS). The consistency of the short diameter measurement with the radiologist was evaluated using Bland-Altman plotting. Based on the segmentation of lymph nodes, the treatment response was assessed automatically with a rule-based program according to the MET-RADS-P criteria. Kappa statistics were used to assess the accuracy and consistency of the treatment response assessment by the deep learning model and two radiologists [attending radiologist (R1) and fellow radiologist (R2)].

RESULTS

The mean DSC and VS of the pelvic lymph node segmentation were 0.82 ± 0.09 and 0.88 ± 0.12, respectively. Bland-Altman plotting showed that most of the lymph node measurements were within the upper and lower limits of agreement (LOA). The accuracies of automated segmentation-based assessment were 0.92 (95% CI: 0.85-0.96), 0.91 (95% CI: 0.86-0.95) and 75% (95% CI: 0.46-0.92) for target lesions, nontarget lesions and nonpathological lesions, respectively. The consistency of treatment response assessment based on automated segmentation and manual segmentation was excellent for target lesions [K value: 0.92 (0.86-0.98)], good for nontarget lesions [0.82 (0.74-0.90)] and moderate for nonpathological lesions [0.71 (0.50-0.92)].

CONCLUSION

The deep learning-based semiautomated algorithm showed high accuracy for the treatment response assessment of pelvic lymph nodes and demonstrated comparable performance with radiologists.

Current Status and Future Perspective on the Management of Lymph Node-Positive Prostate Cancer after Radical Prostatectomy

Pathological lymph node involvement (pN1) after a pelvic lymph node dissection represents one of the most unfavorable prognostic factors for disease recurrence and cancer-specific mortality in prostate cancer. However, optimal management for pN1 patients remains unclear. Thus, the guideline from the European Association of Urology recommends discussing three following management options with pN1 patients after an extended pelvic lymph node dissection, based on nodal involvement characteristics: (i) offer adjuvant androgen-deprivation therapy, (ii) offer adjuvant androgen-deprivation therapy with additional radiotherapy and (iii) offer observation (expectant management) to a patient with ≤2 nodes and a prostate-specific antigen <0.1 ng/mL. Treatment intensification may reduce risks of recurrence and cancer-specific mortality, but it may increase adverse events and impair quality of life. Few randomized control trials for pN1 are under investigation. In addition, there are limited reports on the quality of life and patient-reported outcomes in patients with pN1. Therefore, more research is needed to establish an optimal therapeutic strategy for patients with pN1. This review summarizes current evidence on the treatments available for men with pN1, summarizes randomized control trials that included pN1 prostate cancer, and discusses future perspectives.

Acceptance and efficacy of recommended adjuvant radiotherapy in patients with positive lymph nodes at radical prostatectomy: a preference-based study

PURPOSE

To investigate acceptance and efficacy of recommended adjuvant radiotherapy in patients with positive lymph nodes at radical prostatectomy.

METHODS

Among 495 patients with positive lymph nodes who consecutively underwent radical prostatectomy between 2007 and 2017, we investigated 347 patients who were recommended to undergo adjuvant radiotherapy by a multidisciplinary post-therapeutic tumor board and in whom information whether such treatment was eventually given was available. The median follow-up for censored patients was 5.4 years. Univariate analyses were performed using Kaplan-Meier curves, Mantel-Haenszel hazard ratios and log rank tests. Proportional hazard models for competing risks were used for multivariable analyses.

RESULTS

Adjuvant radiotherapy was independently associated with lower overall mortality and in high-risk patients (Gleason score 8-10 or three or more involved lymph nodes) also with lower prostate cancer-specific mortality. In patients with a Gleason score of 8-10 or three or more involved lymph nodes, the hazard ratio for adjuvant radiotherapy was 0.455 (95% confidence interval 0.257-0.806, p = 0.0069) for overall and 0.426 (95% confidence interval 0.201-0.902, p = 0.0259) for prostate cancer-specific mortality. Among patients receiving adjuvant radiotherapy, there was a trend to lower mortality when such treatment was combined with adjuvant androgen deprivation.

CONCLUSION

Adjuvant radiotherapy decreased mortality in patients with positive lymph nodes at radical prostatectomy with further disease factors but not in patients with low-risk disease. Simultaneous androgen deprivation might increase efficacy. Multidisciplinary recommendations may possibly increase the use of adjuvant radiotherapy in this setting.

Features and management of men with pN1 cM0 prostate cancer after radical prostatectomy and lymphadenectomy: a systematic review of population-based evidence

PURPOSE OF REVIEW

To investigate the features and optimal management of pN+ cM0 prostate cancer (PCa) according to registry-based studies.

RECENT FINDINGS

Up to 15% of PCa patients harbor lymph node invasion (pN+) at radical prostatectomy plus lymph node dissection. Nonetheless, the optimal management strategy in this setting is not well characterized.

SUMMARY

We performed a systematic review including n = 13 studies. Management strategies comprised 13 536 men undergoing observation, 11 149 adjuvant androgen deprivation therapy (aADT), 7,075 adjuvant radiotherapy (aRT) +aADT and 705 aRT. Baseline features showed aggressive PCa in the majority of men. At a median follow-up ranging 48-134months, Cancer-related death was 5% and overall-mortality 16.6%. aADT and aRT alone had no cancer-specific survival or overall survival advantages over observation only and over not performing aRT, respectively. aADT plus aRT yielded a survival benefit compared to observation and aADT, which in one study, were limited to certain intermediate-risk categories. Age, Gleason, Charlson score, positive surgical margins, pathological stage, and positive nodes number, but not prostate specific antigen, were most relevant prognostic factors. Our work further confirmed pN+ PCa is a multifaceted disease and will help future research in defining its optimal management based on different risk categories to maximize survival and patient's quality of life.

Development and validation of the 3D U-Net algorithm for segmentation of pelvic lymph nodes on diffusion-weighted images

Background

The 3D U-Net model has been proved to perform well in the automatic organ segmentation. The aim of this study is to evaluate the feasibility of the 3D U-Net algorithm for the automated detection and segmentation of lymph nodes (LNs) on pelvic diffusion-weighted imaging (DWI) images.

Methods

A total of 393 DWI images of patients suspected of having prostate cancer (PCa) between January 2019 and December 2020 were collected for model development. Seventy-seven DWI images from another group of PCa patients imaged between January 2021 and April 2021 were collected for temporal validation. Segmentation performance was assessed using the Dice score, positive predictive value (PPV), true positive rate (TPR), and volumetric similarity (VS), Hausdorff distance (HD), the Average distance (AVD), and the Mahalanobis distance (MHD) with manual annotation of pelvic LNs as the reference. The accuracy with which the suspicious metastatic LNs (short diameter > 0.8 cm) were detected was evaluated using the area under the curve (AUC) at the patient level, and the precision, recall, and F1-score were determined at the lesion level. The consistency of LN staging on an hold-out test dataset between the model and radiologist was assessed using Cohen’s kappa coefficient.

Results

In the testing set used for model development, the Dice score, TPR, PPV, VS, HD, AVD and MHD values for the segmentation of suspicious LNs were 0.85, 0.82, 0.80, 0.86, 2.02 (mm), 2.01 (mm), and 1.54 (mm) respectively. The precision, recall, and F1-score for the detection of suspicious LNs were 0.97, 0.98 and 0.97, respectively. In the temporal validation dataset, the AUC of the model for identifying PCa patients with suspicious LNs was 0.963 (95% CI: 0.892–0.993). High consistency of LN staging (Kappa = 0.922) was achieved between the model and expert radiologist.

Conclusion

The 3D U-Net algorithm can accurately detect and segment pelvic LNs based on DWI images.

Pathologically Node-Positive Prostate Cancer: Casting for Cure When the Die Is Cast?

The postoperative management of men with lymph node involved prostate cancer (pN+) remains a challenge as there is a general lack of randomized trial data and a range of management strategies. Retrospective studies suggest a variable clinic course for patients with pN+ prostate cancer. Some men progress rapidly to metastatic disease despite further therapies, whereas other men can have a period of prolonged quiescence without adjuvant androgen deprivation therapy (ADT) or radiation therapy (RT). For men who have undergone radical prostatectomy, randomized trial data indicate that the addition of ADT in pN+ disease extends metastasis-free, prostate cancer-specific, and overall survival. Additional retrospective studies suggest that adding RT is potentially beneficial in this setting, improving overall and cancer-specific survival especially in men with certain pathologic parameters. Conversely, men with lower disease burden in their lymph nodes have longer times to progression and may be candidates for observation and salvage therapy as opposed to adjuvant ADT/RT.

Examined and Positive Lymph Node Counts Are Associated with Mortality in Prostate Cancer: A Population-Based Analysis

BACKGROUND

Prostate cancer (PCa) is the third leading cause of death from cancer in the United States. We aimed to disclose the prognostic values of examined (dissected) lymph node (ELN), negative lymph node (NLN), and positive (metastatic) lymph node (PLN) counts and lymph node (LNs) ratio in PCa patients.

METHODS

We extracted data of PCa patients diagnosed between 2004 and 2015 from the Surveillance, Epidemiology, and End Results (SEER) program. We included patients with a histologically confirmed diagnosis having at least one ELN and with the PCa as the primary tumor only.

RESULTS

We have included 96,064 patients. Multivariable Cox proportional hazards regression modelsdisclosed that patients having more ELNs were associated with better survival. However, we demonstrated that patients having more PLNs were associated with worse survival. Additionally, older age, unmarried patients, with Gleason's score of 8-10, T4 and M1 stages and those who received chemotherapy and/or radiation but did not receive surgery were significantly associated with worse PCa survival.

CONCLUSIONS

We have disclosed several independent predictors affecting PCa patients including age, marital status, Gleason's score, T and N stages, having received therapy, surgery, and ELN and PLN counts. Moreover, we demonstrated that patients with lower ELN and higher PLN counts were a high-risk group. We strongly recommend adding the ELN and/or PLN counts into consideration during patient staging/treatment.

Direct comparison of choline PET/CT and MRI in the diagnosis of lymph node metastases in patients with prostate cancer

BACKGROUND

Lymph node detection in prostate cancer is challenging and critical to determine treatment policy. Choline PET/CT (positron emission tomography/computed tomography) and magnetic resonance imaging (MRI) have been used for the evaluation of lymph node metastasis in patients with prostate cancer for the past decade. However, only limited patients underwent direct comparison studies.

PURPOSE

To evaluate the diagnostic performance of choline PET/CT compared with MRI imaging for detecting lymph node metastases in prostate cancer patients.

MATERIAL AND METHODS

Relevant English-language articles published before February 2018 were searched in PubMed database, Embase database, and Cochrane Library databases search using the keywords: (Prostate Neoplasm OR Prostate Cancer OR prostate carcinoma) and (Lymph Node) and (PET/CT OR positron emission tomography/computed tomography) and (choline or 2-hydroxy-N,N,N-trimethylethanaminium) and (magnetic resonance imaging OR MRI). Articles were included that directly compare the diagnostic performance and clinical utility of choline PET/CT and MRI for detecting lymph node metastases in prostate cancer patients. Study quality was assessed with QUADAS criteria. Analyses were performed on a per patient and a per node basis. The pooled sensitivity, specificity, diagnostic odds ratio (DOR), positive likelihood ratio (LR+), and negative likelihood ratio (LR-) were calculated using Meta-Disc 1.4 software. Summary receiver-operating characteristic (SROC) curves constructed.

RESULTS

A total of 362 patients from 8 studies involving fulfilled the inclusion criteria. On patient-based analysis, the pooled sensitivity, specificity, and DOR with a 95% confidence interval (CI) for choline PET/CT imaging were 0.59 (95%CI, 0.50-0.67), 0.92 (95%CI, 0.87-0.96), 17.37 (95%CI, 4.42-68.33), and for MRI imaging, they were 0.52 (95%CI, 0.44-0.61), 0.87 (95%CI, 0.81-0.92), 6.05 (95%CI, 3.09-11.85), respectively. On node-based, the corresponding values for choline PET/CT imaging were 0.51 (95%CI, 0.46-0.57), 0.99 (95%CI, 0.98-0.99), 65.55 (95%CI, 23.55-182.45), and for MRI imaging, they were 0.39 (95%CI, 0.34-0.44), 0.97 (95%CI, 0.96-0.97), 15.86 (95%CI, 8.96-28.05), respectively.

CONCLUSION

Choline PET/CT performed better than MRI imaging in evaluating the lymph nodes metastasis of prostate cancer patients and had the potential to be broadly applied in clinical practice.