Impact of biopsy perineural invasion on the outcomes of patients who underwent radical prostatectomy: a systematic review and meta-analysis

Clinical significance of location of perineural cancer invasion detected on prostate needle core biopsy

The clinical impact of site-specific perineural invasion (PNI) in prostate cancer remains poorly understood. We compared radical prostatectomy findings and oncologic outcomes in 434 patients with single-site PNI on systematic sextant biopsy. PNI was present in the right apex (n = 62; 14%), right mid (n = 70; 16%), right base (n = 89; 21%), left apex (n = 64; 15%), left mid (n = 58; 13%), and left base (n = 91; 21%). There were no significant differences in biopsy or prostatectomy findings, when comparing apex vs. mid vs. base PNI. Univariate analysis revealed that apex-localized PNI was associated with a significantly higher risk of progression, compared with base (P = 0.037) or mid/base (P = 0.024) PNI. Multivariable analysis showed that apex-localized PNI was an independent risk factor for progression (hazard ratio 2.049, P = 0.002). Among biopsies demonstrating PNI at one sextant site, apex-localized PNI is independently associated with poorer prognosis, though not worse histopathologic features on prostatectomy, compared with mid or base PNI.

Clinical impact of perineural invasion encircled completely vs. incompletely by prostate cancer on needle core biopsy

The clinical significance of the pattern or degree of perineural invasion (PNI) by prostate cancer remains largely unknown. We herein assessed radical prostatectomy findings and postoperative oncologic outcomes in 125 patients who had undergone systematic sextant prostate biopsy exhibiting only a single focus of PNI encircled completely (n = 57; 46 %) vs. incompletely (n = 68; 54 %) by cancer. Between these two cohorts, there were no significant differences in clinicopathological features on biopsy or prostatectomy, including tumor grade, stage, and length or volume, and surgical margin status, as well as the need for adjuvant therapy immediately after prostatectomy. Similarly, survival analysis demonstrated no significant difference in the risk of disease progression following prostatectomy in patients with encircled vs. non-encircled PNI on biopsy (P = 0.679). When the non-encircled cases were further divided into four groups [i.e. 1-25 % enclosed (n = 12; 18 %), 26-50 % enclosed (n = 18; 26 %), 51-75 % enclosed (n = 10; 15 %), 76-99 % enclosed (n = 28; 41 %)], the rates of progression-free survival were comparable among the five groups (P = 0.954). In prostate biopsy specimens exhibiting PNI at only one focus, the degree of nerve involvement thus appears to have little clinical impact. Accordingly, PNI detected on prostate biopsy may need to be similarly taken into consideration irrespective of the degree of nerve involvement.

Clinical Significance of Perineural Invasion by Prostate Cancer Detected on Needle Core Biopsy

OBJECTIVES

The clinical impact of the laterality of perineural invasion (PNI) by prostate cancer remains poorly understood. We herein compared radical prostatectomy (RP) findings and long-term oncologic outcomes in patients with prostate cancer with PNI in two prostate biopsy (PBx) sites.

METHODS

We retrospectively assessed 170 consecutive patients undergoing systematic sextant PBx where PNI had been detected in two of six PBx sites, followed by RP.

RESULTS

PNI occurred unilaterally in 140 (82.4%) cases and bilaterally in 30 (17.6%) cases. Compared with unilateral PNI, bilateral PNI was significantly associated with a higher number of cancer-positive sites and longer total tumor length on PBx. However, there were no significant differences in RP findings, including tumor grade/stage and tumor volume, between unilateral and bilateral PNI cohorts. Kaplan-Meier analysis revealed that patients with bilateral PNI had a significantly higher risk of disease progression after RP than those with unilateral PNI (P = .038). In multivariate analysis, bilateral PNI (vs unilateral PNI) showed significance for progression (hazard ratio, 2.281; P = .023).

CONCLUSIONS

In PBx specimens exhibiting PNI in two sextant sites, bilateral PNI was found to be associated with poorer prognosis as an independent predictor but not worse histopathologic features in RP specimens compared with unilateral PNI.

Single-cell RNA sequencing reveals intratumoral heterogeneity and potential mechanisms of malignant progression in prostate cancer with perineural invasion

Background: Prostate cancer (PCa) is the second most common cancer among men worldwide. Perineural invasion (PNI) was a prominent characteristic of PCa, which was recognized as a key factor in promoting PCa progression. As a complex and heterogeneous disease, its true condition is difficult to explain thoroughly with conventional bulk RNA sequencing. Thus, an improved understanding of PNI-PCa progression at the single-cell level is needed. Methods: In this study, we performed scRNAseq on tumor tissues of three PNI-PCa patients. Principal component analysis (PCA) and Uniform manifold approximation and projection (UMAP) were used to reduce dimensionality and visualize the cellular composition of tumor tissues. The differently expressed genes among each cluster were identified by EdgeR. GO enrichment analysis was used to understand the roles of genes within the clusters. Pseudotime cell trajectory was used to reveal the molecular pathways underlying cell fate decisions and identify genes whose expression changed as the cells underwent transition. We applied CellPhoneDB to identify cell-cell interactions among the epithelial and neural cells in PNI-PCa. Results: Analysis of the ∼17,000 single-cell transcriptomes in three PNI prostate cancer tissues, we identified 12 major cell clusters, including neural cells and two epithelial subtypes with different expression profiles. We found that basal/intermediate epithelial cell subtypes highly expressed PCa progression-related genes, including PIGR, MMP7, and AGR2. Pseudotime trajectory analysis showed that luminal epithelial cells could be the initiating cells and transition to based/intermediate cells. Gene ontology (GO) enrichment analysis showed that pathways related to cancer progressions, such as lipid catabolic and fatty acid metabolic processes, were significantly enriched in basal/intermediate cells. Our analysis also suggested that basal/intermediate cells communicate closely with neural cells played a potential role in PNI-PCa progression. Conclusion: These results provide our understanding of PNI-PCa cellular heterogeneity and characterize the potential role of basal/intermediate cells in the PNI-PCa progression.

The Role of Perineural Invasion in Prostate Cancer and Its Prognostic Significance

Simple Summary

Prostate cancer is one of the most frequently diagnosed cancers in men worldwide. Perineural invasion (PNI), the movement of cancer cells along nerves, is a commonly observed approach to tumor spread and is important in both research and clinical practice of prostate cancer. However, despite many studies reporting on molecules and pathways involved in PNI, understanding its clinical relevance remains insufficient. In this review, we aim to summarize the current knowledge of mechanisms and prognostic significance of PNI in prostate cancer, which may provide new perspectives for future studies and improved treatment.

Abstract

Perineural invasion (PNI) is a common indication of tumor metastasis that can be detected in multiple malignancies, including prostate cancer. In the development of PNI, tumor cells closely interact with the nerve components in the tumor microenvironment and create the perineural niche, which provides a supportive surrounding for their survival and invasion and benefits the nerve cells. Various transcription factors, cytokines, chemokines, and their related signaling pathways have been reported to be important in the progress of PNI. Nevertheless, the current understanding of the molecular mechanism of PNI is still very limited. Clinically, PNI is commonly associated with adverse clinicopathological parameters and poor outcomes for prostate cancer patients. However, whether PNI could act as an independent prognostic predictor remains controversial among studies due to inconsistent research aim and endpoint, sample type, statistical methods, and, most importantly, the definition and inclusion criteria. In this review, we provide a summary and comparison of the prognostic significance of PNI in prostate cancer based on existing literature and propose that a more standardized description of PNI would be helpful for a better understanding of its clinical relevance.

Detection of perineural invasion in prostate needle biopsies with deep neural networks

The presence of perineural invasion (PNI) by carcinoma in prostate biopsies has been shown to be associated with poor prognosis. The assessment and quantification of PNI are, however, labor intensive. To aid pathologists in this task, we developed an artificial intelligence (AI) algorithm based on deep neural networks. We collected, digitized, and pixel-wise annotated the PNI findings in each of the approximately 80,000 biopsy cores from the 7406 men who underwent biopsy in a screening trial between 2012 and 2014. In total, 485 biopsy cores showed PNI. We also digitized more than 10% (n = 8318) of the PNI negative biopsy cores. Digitized biopsies from a random selection of 80% of the men were used to build the AI algorithm, while 20% were used to evaluate its performance. For detecting PNI in prostate biopsy cores, the AI had an estimated area under the receiver operating characteristics curve of 0.98 (95% CI 0.97-0.99) based on 106 PNI positive cores and 1652 PNI negative cores in the independent test set. For a pre-specified operating point, this translates to sensitivity of 0.87 and specificity of 0.97. The corresponding positive and negative predictive values were 0.67 and 0.99, respectively. The concordance of the AI with pathologists, measured by mean pairwise Cohen's kappa (0.74), was comparable to inter-pathologist concordance (0.68 to 0.75). The proposed algorithm detects PNI in prostate biopsies with acceptable performance. This could aid pathologists by reducing the number of biopsies that need to be assessed for PNI and by highlighting regions of diagnostic interest.

The Clinical Significance of Perineural Invasion by Prostate Cancer on Needle Core Biopsy

CONTEXT.—

Perineural invasion (PNI) by prostate cancer has been associated with adverse pathology, including extraprostatic extension. However, the significance of PNI quantification on prostate biopsy (PBx) remains unclear.

OBJECTIVE.—

To compare radical prostatectomy (RP) findings and long-term outcomes in patients whose PBx had exhibited PNI.

DESIGN.—

We assessed 497 consecutive patients undergoing sextant (6-site/≥12-core) PBx showing conventional adenocarcinoma followed by RP.

RESULTS.—

PNI was found in 1 (n = 290)/2 (n = 132)/3 (n = 47)/4 (n = 19)/5 (n = 5)/6 (n = 4) of the sites/regions of PBx. Compared with a single PNI site, multiple PNIs were significantly associated with higher preoperative prostate-specific antigen, higher Grade Group (GG) on PBx or RP, higher pT or pN category, positive surgical margin, and larger estimated tumor volume. When compared in subgroups of patients based on PBx GG, significant differences in RP GG (GG1-3), pT (GG1-2/GG1-3/GG2/GG3), surgical margin status (GG1-3/GG3/GG5), or tumor volume (GG1-2/GG1-3/GG2/GG3) between 1 versus multiple PNIs were observed. Moreover, there were significant differences in prostate-specific antigen (PNI sites: 1-2 versus 3-6/1-3 versus 4-6/1-4 versus 5-6), RP GG (1-3 versus 4-6/1-4 versus 5-6), pT (1-2 versus 3-6/1-3 versus 4-6), pN (1-3 versus 4-6), or tumor volume (1-2 versus 3-6/1-4 versus 5-6). Outcome analysis revealed significantly higher risks of disease progression in the entire cohort or PBx GG1-2/GG1-3/GG2/GG3/GG5 cases showing 2 to 6 PNIs, compared with respective controls with 1-site PNI. In multivariate analysis, multisite PNI was an independent predictor for progression (hazard ratio = 1.556, P = .03).

CONCLUSIONS.—

Multiple sites of PNI on PBx were associated with worse histopathologic features in RP specimens and poorer prognosis. PNI may thus need to be specified, if present, in every sextant site on PBx, especially those showing GG1-3 cancer.

Combined Longitudinal Clinical and Autopsy Phenomic Assessment in Lethal Metastatic Prostate Cancer: Recommendations for Advancing Precision Medicine

BACKGROUND

Systematic identification of data essential for outcome prediction in metastatic prostate cancer (mPC) would accelerate development of precision oncology.

OBJECTIVE

To identify novel phenotypes and features associated with mPC outcome, and to identify biomarker and data requirements to be tested in future precision oncology trials.

DESIGN SETTING AND PARTICIPANTS

We analyzed deep longitudinal clinical, neuroendocrine expression, and autopsy data of 33 men who died from mPC between 1995 and 2004 (PELICAN33), and related findings to mPC biomarkers reported in the literature.

INTERVENTION

Thirty-three men prospectively consented to participate in an integrated clinical-molecular rapid autopsy study of mPC.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Data exploration with correction for multiple testing and survival analysis from the time of diagnosis to time to death and time to first occurrence of severe pain as outcomes were carried out. The effect of seven complications on the modeled probability of dying within 2 yr after presenting with the complication was evaluated using logistic regression.

RESULTS AND LIMITATIONS

Feature exploration revealed novel phenotypes related to mPC outcome. Four complications (pleural effusion, severe anemia, severe or controlled pain, and bone fracture) predict the likelihood of death within 2 yr. Men with Gleason grade group 5 cancers developed severe pain sooner than those with lower-grade tumors. Surprisingly, neuroendocrine (NE) differentiation was frequently observed in the setting of high serum prostate-specific antigen (PSA) levels (≥30 ng/ml). In 4/33 patients, no controlled (requiring analgesics) or severe pain was detected, and strikingly, 14/15 metastatic sites studied in these men did not express NE markers, suggesting an inverse relationship between NE differentiation and pain in mPC. Intracranial subdural metastasis is common (36%) and is usually clinically undetected. Categorization of "skeletal-related events" complications used in recent studies likely obscures the understanding of spinal cord compression and fracture. Early death from prostate cancer was identified in a subgroup of men with a low longitudinal PSA bandwidth. Cachexia is common (body mass index <0.89 in 24/31 patients) but limited to the last year of life. Biomarker review identified 30 categories of mPC biomarkers in need of winnowing in future trials. All findings require validation in larger cohorts, preferably alongside data from this study.

CONCLUSIONS

The study identified novel outcome subgroups for future validation and provides "vision for mPC precision oncology 2020-2050" draft recommendations for future data collection and biomarker studies.

PATIENT SUMMARY

To better understand variation in metastatic prostate cancer behavior, we assembled and analyzed longitudinal clinical and autopsy records in 33 men. We identified novel outcomes, phenotypes, and aspects of disease burden to be tested and refined in future trials.

Investigation of Neural Microenvironment in Prostate Cancer in Context of Neural Density, Perineural Invasion, and Neuroendocrine Profile of Tumors

Background

Cancer stroma contains the neural compartment with specific components and action. Neural microenvironment processing includes among others axonogenesis, perineural invasion (PNI), neurosignaling, and tumor cell neural/neuroendocrine differentiation. Growing data suggest that tumor-neural crosstalk plays an important function in prostate cancer (PCa) biology. However, the mechanisms involved in PNI and axonogenesis, as well as their patho-clinical correlations in this tumor are unclear.

Methods

The present study was carried out on FFPE samples of 73 PCa and 15 benign prostate (BP) cases. Immunohistochemistry with neural markers PGP9.5, TH, and NFP was performed on constructed TMAs and selected tissue sections. The analyzed parameters of tumor innervation included small nerve density (ND) measured on pan-neural marker (PGP9.5) and TH s4tained slides, as well assessment of PNI presence and morphology. The qualitative and topographic aspects were studied. In addition, the expression of neuroendocrine marker chromogranin and NPY was assessed with dedicated indexes. The correlations of the above parameters with basic patho-clinical data such as patients’ age, tumor stage, grade, angioinvasion, and ERG status were examined.

Results

The study showed that innervation parameters differed between cancer and BP. The neural network in PCa revealed heterogeneity, and ND PGP9.5 in tumor was significantly lower than in its periphery. The density of sympathetic TH-positive fibers and its proportion to all fibers was lower in cancer than in the periphery and BP samples. Perineural invasion was confirmed in 76% of cases, usually multifocally, occurring more commonly in tumors with a higher grade. NPY expression in PCa cells was common with its intensity often rising towards PNI. ERG+ tumors showed higher ND, more frequent PNI, and a higher stage. Moreover, chromogranin-positive cells were more pronounced in PCa with higher NPY expression.

Conclusions

The analysis showed an irregular axonal network in prostate cancer with higher neural density (panneural and adrenergic) in the surroundings and the invasive front. ND and PNI interrelated with NPY expression, neuroendocrine differentiation, and ERG status. The above findings support new evidence for the presence of autocrine and paracrine interactions in prostate cancer neural microenvironment.

Interobserver reproducibility of perineural invasion of prostatic adenocarcinoma in needle biopsies

Numerous studies have shown a correlation between perineural invasion (PNI) in prostate biopsies and outcome. The reporting of PNI varies widely in the literature. While the interobserver variability of prostate cancer grading has been studied extensively, less is known regarding the reproducibility of PNI. A total of 212 biopsy cores from a population-based screening trial were included in this study (106 with and 106 without PNI according to the original pathology reports). The glass slides were scanned and circulated among four pathologists with a special interest in urological pathology for assessment of PNI. Discordant cases were stained by immunohistochemistry for S-100 protein. PNI was diagnosed by all four observers in 34.0% of cases, while 41.5% were considered to be negative for PNI. In 24.5% of cases, there was a disagreement between the observers. The kappa for interobserver variability was 0.67–0.75 (mean 0.73). The observations from one participant were compared with data from the original reports, and a kappa for intraobserver variability of 0.87 was achieved. Based on immunohistochemical findings among discordant cases, 88.6% had PNI while 11.4% did not. The most common diagnostic pitfall was the presence of bundles of stroma or smooth muscle. It was noted in a few cases that collagenous micronodules could be mistaken for a nerve. The distance between cancer and nerve was another cause of disagreement. Although the results suggest that the reproducibility of PNI may be greater than that of prostate cancer grading, there is still a need for improvement and standardization.

Perineural invasion in prostate needle biopsy: Prognostic value on radical prostatectomy and active surveillance

PURPOSE

The aim of this study was to evaluate the clinical impact of perineural invasion (PNI) in prostate biopsy in patients submitted to radical prostatectomy and on active surveillance (AS).

MATERIALS AND METHODS

We performed a single center, retrospective, cohort study on patients diagnosed with clinically localized prostate cancer and submitted to radical prostatectomy between January 2010 and December 2016. We evaluated clinical and anatomopathological characteristics from the biopsy and radical prostatectomy specimen and correlated with biochemical recurrence (BCR) using a survival analysis. We also evaluated the impact of PNI in patients with criteria for active surveillance.

RESULTS

The cohort analyzed consists of 107 patients, with a mean age of 63.1 years and a mean PSA prior to biopsy of 7.8 ng/ml. In prostate biopsy, 66.4% of the patients had a Gleason score of 6, 30.9% had a Gleason score of 7, and 2.7% had a Gleason score of 8 or higher, with PNI being detected in 57 (53.3%) of the patients. Regarding the anatomopathological characteristics of the surgical specimen, invasion of the seminal vesicles was observed in 6.5%, lymph nodes involvement in 9.3% and positive surgical margins in 27.1% of the cases. During follow-up, BCR was recorded in 24.3% of cases. Clinicopathological features were stratified according to the presence or absence of PNI, with statistical significance in relation to the Gleason Score (p = 0.001), pathologic T stage (p = 0.001), D'Amico risk (p = 0.002) and upstaging of the Gleason score (p = 0.045). The survival analysis revealed a relationship between PNI and BCR (hazard ratio = 2.98; 95% CI: 1.36-6.58; p = 0.007). Regarding the men potentially eligible for AS, the presence of PNI on the biopsy presented a significant relation with Gleason upgrade (p = 0.004) and extraprostatic extension (p = 0.017).

CONCLUSIONS

The presence of PNI in prostate biopsy is related to adverse anatomopathological factors, being a potential predictor of BCR and have a possible role in the selection of patients for AS.

Long-term Oncologic Impact of Positive Anterior and Posterior Surgical Margins After Radical Prostatectomy

OBJECTIVE

The objective of this study was to evaluate the impact of the anterior/posterior status of positive surgical margin (PSM) on long-term outcomes after radical prostatectomy for prostate cancer.

PATIENTS AND METHODS

We included 391 consecutive PSM patients after radical prostatectomy between 1993 and 2007 excluding cases with multiple location PSM or lack of anterior/posterior status data. The oncologic impact of anterior-PSM and posterior-PSM were examined by Kaplan-Meier analysis and the Cox proportional hazards model.

RESULTS

There were 115 cases (29.4%) with apex-PSM, 257 cases (65.7%) with peripheral PSM, and 19 cases (4.9%) with bladder neck PSM. Among the 257 peripheral PSM cases, 58 cases (22.6%) were with anterior-PSM, 174 cases (67.7%) were with posterior-PSM, and 25 cases (9.7%) were with both anterior and posterior PSM. Over a median follow-up of 12.6 years, patients with anterior-PSM, especially those with low to intermediate Gleason score (≤7), showed a biochemical recurrence (BCR) prognosis similar to those with apex-PSM. In contrast, patients with posterior-PSM showed significantly higher BCR risk on both univariate and multivariate analyses when compared with those with apex-PSM. No impact on metastasis-free survival or overall survival was observed.

CONCLUSIONS

In our study, we found that prostate cancer patients with anterior-PSM showed a more favorable BCR prognosis similar to those with apex-PSM when comparing to patients with posterior-PSM. Our study results may help physicians to choose different treatment options for patients diagnosed with different PSM status including considering further adjuvant treatment for patients with posterior-PSM.

Investigating association of perineural invasion on prostate biopsy with Gleason score upgrading at prostatectomy: A multi-institutional analysis

Background

The significance of perineural invasion (PNI) in prostate cancer (PC) is unclear. A recent report of patients with pT2N0R0 PC found that PNI at prostatectomy was independently associated with higher Gleason score and more diffuse prostatic disease. We aimed to test our hypothesis that PNI on prostate biopsy in pT2N0R0 patients is associated with increased Gleason score upgrading at prostatectomy.

Methods

We identified 2892 patients status post prostatectomy with pT2N0R0 PC from three institutions, diagnosed between 1 January 2008 and 31 December 2014. Multivariable logistic regression (MVA) was used to evaluate the association between prostate biopsy PNI status and surgical Gleason upgrading, while controlling for potential confounders.

Results

Of the 2892 patients identified, 14% had PNI on biopsy, of whom 21% had surgical Gleason upgrading, while 28% without PNI on biopsy had such upgrading (P < .01). On MVA, the odds ratio (OR) of surgical Gleason upgrading for patients with biopsy PNI relative to patients without biopsy PNI was 0.69 (P < .01). The variables associated with surgical Gleason upgrading were age ≤60 years (OR 1.22, P = .02) and preoperative PSA >4 ng/mL (OR 1.26, P = .02).

Conclusions

In post‐prostatectomy patients with favorable‐risk PC, PNI on prostate biopsy was not associated with surgical Gleason score upgrading. This may be due to the association of PNI with more diffuse disease, leading to increased biopsy tumor yield and grading accuracy. These findings suggest that in this setting, biopsy PNI alone should not be a concern for more aggressive disease requiring pathologic confirmation or intervention. This may help guide treatment decision‐making for men debating active surveillance, radiation, and surgery.