Detailed analysis of patients with metastasis to the prostatic anterior fat pad lymph nodes: a multi-institutional study

Fluorescence-guided radical prostatectomy

Robotic-assisted laparoscopic radical prostatectomy represents one of the most common operations in urologic oncology and involves several critical technical steps including pelvic lymph node dissection, cavernous nerve sparing and vesicourethral anastomosis. The quality of performing these steps is linked to functional and oncological outcomes. Indocyanine green [ICG] is a non-radioactive, water-soluble compound which allows for enhanced visualization with near-infrared fluorescence of both anatomical structures and vasculature during complex abdominal operations such as prostatectomy. During the last decade, several investigators have examined the value and role of ICG fluorescence during prostatectomy. In this review, we sought to evaluate the body of evidence for fluorescence-guided robotic prostatectomy as well as assess potential future areas of investigation with this technology.

[CASE OF LOW-RISK PROSTATE CANCER WITH LYMPH NODE METASTASIS IN THE ANTERIOR PROSTATIC FAT TISSUE]

A 78-year-old man with a prostate-specific antigen level of 10 ng/mL was referred to our hospital. Magnetic resonance imaging revealed a Prostate Imaging-Reporting and Data System category of 5 in the apex transition zone. Transrectal and transperineal prostate needle biopsies were performed at a total of 20 sites. A well-differentiated adenocarcinoma with a Gleason score of 3+3 was detected on the right peripheral zone of the biopsied specimen. There were no apparent metastases, and robot-assisted radical prostatectomy was performed (Lesion 1: 30 mm lesion with a Gleason score of 4+5, EPE1, RM1, ly0, v0, pn1, sv0 in the bilateral transitional zones; Lesion 2: 4 mm lesion with a Gleason score of 3+3, EPE0, RM0, ly0, v0, pn0, sv0 in the left peripheral zone). Lymph node metastasis was found in the separately submitted anterior prostatic fat tissue. Removal of the anterior prostatic fat tissue is a simple procedure and is considered useful for evaluating the stump, and in this hospital, the tissue is routinely submitted for pathological diagnosis. It is extremely unlikely that lymph nodes will be found in the anterior prostatic fat tissue, and it is even less likely that any lymph node in the tissue will contain lymph node metastases. We therefore report a case of incidental discovery of lymph node metastasis in the anterior prostatic fat tissue at our hospital.

Anterior prostate fat resection during prostatectomy: a histopathologic review

A common practice during robot-assisted radical prostatectomy (RARP) is to dissect the anterior prostate space and send this anterior fat sample for histological analysis to assess for the presence of any malignant tissue. Theoretically, this may help with prognostication and oncological control, however, is this a futile process? To determine the incidence of malignant tissue found in the anterior prostate (APF) samples sent for histological review. All RARP patients within a single urology centre over a 2-year period were included. The pathology results of these patients were reviewed and the proportion of patients with APF sent were analysed for presence of lymph nodes and malignant tissue. 657 patients were identified. 358 patients had APF samples reviewed by the histopathologists. 38 (10.6%) samples had lymph nodes identified within the sample. Malignant lymph node tissue was found in one patient (0.3%). Given the yield of malignancy found in APF samples is so small and the financial and time burden on pathology services, this process is not worthwhile.

The impact of histopathological analysis of anterior peri-prostatic fat in radical prostatectomy patients

Objective:

To determine the usefulness of histopathological analysis of peri-prostatic fat in a cohort of prostate cancer patients undergoing radical prostatectomy (RP) in an Australian regional centre. During RP, removal of the anterior peri-prostatic fat (APPF) is commonly undertaken; some surgeons routinely request histopathological analysis of this specimen. Previously published data show positive cancer detection in peri-prostatic fat in 0–2.5% of specimens and positive yields are mostly detected in patients with adverse pathological features.

Subjects and methods:

All patients undergoing RP in a regional urology unit in Queensland were identified. Pathology results were examined retrospectively to determine the rate of cancer involvement in APPF specimens and medical records were reviewed to assess any clinical impact.

Results:

APPF was sent for pathological analysis in 270/298 (90%) of patients undergoing RP. Prostate cancer was detected in one sample containing a single involved lymph node in a patient with Gleason 5 + 4 = 9 prostate cancer and pathological stage pT3bN1R1Mx. The presence of the cancer in the APPF did not affect the decision to offer adjuvant radiotherapy.

Conclusion:

In our population, we have identified a positive cancer yield of 0.3% in APPF specimens. When combined with all previously published series, we found positive cancer detection in 72/7391 (1%) specimens, and most patients with positive fat involvement had adverse pre-operative and final pathological features. Surgeons may consider omitting sending APPF specimens for analysis based on the low yield with little additional staging information. If surgeons continue this practice, they should consider selectively requesting analysis in intermediate- and high-risk patients.

Level of evidence:

2b

Impact of prostatic anterior fat pads with lymph node staging in prostate cancer

Background: Several reports have revealed the presence of lymph nodes in the prostatic anterior fat pad (PAFP). To date, no study has described the characteristics of Taiwanese patients harboring PAFP lymph nodes with metastatic prostate cancer involvement.

Method: Between December 2006 and May 2015, a total of 849 consecutive patients underwent robot-assisted laparoscopic radical prostatectomy with PAFP dissection. Pathological examination of the dissected PAFP was conducted to assess the presence of lymphoid tissue and prostate cancer involvement.

Results: Of the 849 patients, 76 (9.0%) had 1-3 PAFP lymph nodes. Moreover, 11 (1.3%) of the 76 patients had positive lymph node metastases of prostate cancer in the PAFP; 5 (0.6%) of the 11 patients, who had negative pelvic lymph node involvement, were upstaged because of positive metastases in PAFP lymph nodes. Among the 76 patients having PAFP lymph nodes, metastatic lymph nodes were associated with the clinical T stage, preoperative Gleason score, pathological T stage, and pathological N stage (p < 0.001). Patients with pathological seminal vesicle invasion and a higher surgical Gleason score also exhibited PAFP lymph node metastases (p < 0.005).

Conclusion: Our data show that 9.0% of patients had PAFP lymph nodes and that 1.3% had prostate cancer metastases. Additionally, 0.6% of patients were upstaged because of positive metastases in PAFP lymph nodes. Because of the pathological analysis of the PAFP, a few patients were upstaged. Thus, routine pathological analysis of the PAFP should only be conducted for those with higher preoperative prostate-specific antigen, higher Gleason score, and advanced T stage observations.

Metastatic Involvement of the Prostatic Anterior Fat Pad: Implications for the Pathologist

OBJECTIVES

There is little information regarding the utility of pathologic evaluation of the prostatic anterior fat pad (PAFP) in patients with a low preoperative probability of recurrence. Our study aimed to determine the utility of PAFP pathologic examination, especially for this group of patients.

METHODS

We analyzed a tertiary care academic center's radical prostatectomy (RP) specimens from 2009 to 2017.

RESULTS

Of 602 RP specimens, 420(70%) included the PAFP; four of 420 (1%) had lymph node involvement (LNI) in the PAFP. In two of four cases with LNI in the PAFP, this was the only site of LNI. Of these two cases, one occurred in a patient with low probability of recurrence and involved a nonpalpable PAFP lymph node.

CONCLUSIONS

Pathologic evaluation of the PAFP may be useful even in patients with low probability of recurrence because it may change staging by detecting metastatic involvement of small PAFP lymph nodes.

Can Anterior Prostatic Fat Harbor Prostate Cancer Metastasis? A Prospective Cohort Study

OBJECTIVES

Traditionally anterior prostatic fat (APF) hasn't been included in pelvic lymph node (LN) dissection templates following radical prostatectomy. In this study we evaluate the incidence of lymphoid tissue in the APF and the incidence of LN metastasis in APF in patients who have undergone robotic-assisted laparoscopic radical prostatectomy (RALP).

METHODS

A prospective database of RALP has been maintained between January 2010 and September 2015. APF is routinely excised and sent separately for histopathological evaluation to identify lymphoid tissue and metastatic prostate cancer.

RESULTS

A total of 629 underwent RALP. Forty-six (7.3%) of the patients had lymphoid tissue on histopathological evaluation. Two patients had meta-static disease. Both patients with positive LNs were intermediate risk on pre-operative evolution (A-PSA 16.6 ng/ml, Gleason 3 + 4; B PSA 7.3 ng/ml, Gleason 4 + 3) and upgraded on final prostate pathological evaluation to high risk disease (A-Gleason 4 + 5, pT3b, B-Gleason 4 + 3, pT4).

CONCLUSION

There appears to be lymphatic drainage to the APF from the prostate. Hence APF should be included in pelvic LN dissection templates when lymphadenectomy is contemplated in patients undergoing radical prostatectomy.

Lymph node staging in prostate cancer: perspective for the pathologist

Pelvic lymph node dissection (PLND) currently represents the gold standard method for nodal staging in the setting of localised prostate cancer and may also have a therapeutic benefit in certain patients. The histopathological evaluation of PLND specimens plays a critical role in accurate lymph node staging, however there is currently a lack of consensus regarding the optimum approach and no quality parameters are in place. In addition, there are no guidelines as to the handling of less commonly encountered nodal specimens such as those identified within the anterior fat pad. This summary provides an overview of pertinent issues regarding lymph node staging in prostate cancer, with a focus on the histopathological evaluation of resected nodal specimens. We hope that this review will further the discussion on how to achieve a more standardised approach to the processing and reporting of PLND specimens in the setting of prostate cancer.

Update on histopathological evaluation of lymphadenectomy specimens from prostate cancer patients

BACKGROUND

Metastases to lymph nodes (LNs) represent an unfavorable prognostic factor in patients with prostate cancer (PCa). Histological examination represents the gold standard in the evaluation of the lymphadenectomy (LND) specimens for the presence of secondary deposits.

METHODS AND RESULTS

The metastatic detection rate can vary according to the approach adopted in the microscopic analysis of the LNs, which includes frozen-section examination, total inclusion of the tissue with and without whole-mount sections, serial sectioning, and the application of immunohistochemistry. The assessment of the sentinel LN, the search for micrometastases, and the evaluation of atypical LN metastatic sites further contribute to the detection of the metastatic spread.

CONCLUSION

In this review, an update on the histopathological evaluation of LND specimens in patients with PCa is given, and focus is made on their clinical and prognostic significance.

Does anterior prostatic fat tissue removed during robotic radical prostatectomy contain any lymph nodes?

INTRODUCTION

We investigated whether anterior periprostatic fat (APPF) tissue removed during robotic radical prostatectomy (RARP) contains any lymph nodes (LNs).

MATERIAL AND METHODS

APPF tissues removed during RARP in 129 patients were evaluated histopathologically. Correlation with postoperative pathologic stage was made. Patients with a history of previous prostate or bladder surgery and radiation therapy were excluded.

RESULTS

Mean patient age, serum prostate specific antigen (PSA), prostate weight and body mass index (BMI) were 62.2 ±5.5 (range 45-74), 9.3 ±6.3 ng/dl (range 0.26-30.3), 60.3 ±27.2 grams (range 11.0-180) and 26.6 ±1.9 kg/m(2) (range 20.0-30.3), respectively. Overall, LNs in APPF tissues were detected in 14 (10.9%) patients with a mean LN yield of 1.1 ±0.7 LNs (range, 1-3). Among those found, no metastatic LN was detected. Of the patients with pT2a (n = 22), pT2b (n = 15), pT2c (n = 62) and pT3a (n = 21) disease, LNs in APPF tissues were detected in 1 (4.6%), 1 (6.7%), 11 (17.7%) and 1 (4.8%) patient in each group, respectively. Among the patients, LNs in APPF tissues were detected in 0 (0%), 5 (35.7%), 8 (57.1%) and 1 (7.1%) patients of underweight, optimal weight, overweight and obese patients due to body mass index, respectively.

CONCLUSIONS

In our series, LNs were detected in around 10% of the patients. Therefore, this fat should, not be pushed back during RARP but should be removed and sent for pathologic evaluation. Although no metastatic LN was detected in our series, the presence of metastatic LNs might have an impact on the oncologic outcomes of the patients and warrants further research.

Oncologic outcomes in men with metastasis to the prostatic anterior fat pad lymph nodes: a multi-institution international study

Background

The presence of lymph nodes (LN) within the prostatic anterior fat pad (PAFP) has been reported in several recent reports. These PAFP LNs rarely harbor metastatic disease, and the characteristics of patients with PAFP LN metastasis are not well-described in the literature. Our previous study suggested that metastatic disease to the PAFP LN was associated with less severe oncologic outcomes than those that involve the pelvic lymph node (PLN). Therefore, the objective of this study is to assess the oncologic outcome of prostate cancer (PCa) patients with PAFP LN metastasis in a larger patient population.

Methods

Data were analyzed on 8800 patients from eleven international centers in three countries. Eighty-eight patients were found to have metastatic disease to the PAFP LNs (PAFP+) and 206 men had isolated metastasis to the pelvic LNs (PLN+). Clinicopathologic features were compared using ANOVA and Chi square tests. The Kaplan-Meier method was used to calculate the time to biochemical recurrence (BCR).

Results

Of the eighty-eight patients with PAFP LN metastasis, sixty-three (71.6 %) were up-staged based on the pathologic analysis of PAFP and eight (9.1 %) had a low-risk disease. Patients with LNs present in the PAFP had a higher incidence of biopsy Gleason score (GS) 8–10, pathologic N1 disease, and positive surgical margin in prostatectomy specimens than those with no LNs detected in the PAFP. Men who were PAFP+ with or without PLN involvement had more aggressive pathologic features than those with PLN disease only. However, there was no significant difference in BCR-free survival regardless of adjuvant therapy. In 300 patients who underwent PAFP LN mapping, 65 LNs were detected. It was also found that 44 out of 65 (67.7 %) nodes were located in the middle portion of the PAFP.

Conclusions

There was no significant difference in the rate of BCR between the PAFP LN+ and PLN+ groups. The PAFP likely represents a landing zone that is different from the PLNs for PCa metastasis. Therefore, the removal and pathologic analysis of PAFP should be adopted as a standard procedure in all patients undergoing radical prostatectomy.

Electronic supplementary material

The online version of this article (doi:10.1186/s12894-015-0070-1) contains supplementary material, which is available to authorized users.

The surgical learning curve for robotic-assisted laparoscopic radical prostatectomy: experience of a single surgeon with 500 cases in Taiwan, China

To analyze the learning curve for cancer control from an initial 250 cases (Group I) and subsequent 250 cases (Group II) of robotic-assisted laparoscopic radical prostatectomy (RALP) performed by a single surgeon. Five hundred consecutive patients with clinically localized prostate cancer received RALP and were evaluated. Surgical parameters and perioperative complications were compared between the groups. Positive surgical margin (PSM) and biochemical recurrence (BCR) were assessed as cancer control outcomes. Patients in Group II had significantly more advanced prostate cancer than those in Group I (22.2% vs 14.2%, respectively, with Gleason score 8–10, P= 0.033; 12.8% vs 5.6%, respectively, with clinical stage T3, P= 0.017). The incidence of PSM in pT3 was decreased significantly from 49% in Group I to 32.6% in Group II. A meaningful trend was noted for a decreasing PSM rate with each consecutive group of 50 cases, including pT3 and high-risk patients. Neurovascular bundle (NVB) preservation was significantly influenced by the PSM in high-risk patients (84.1% in the preservation group vs 43.9% in the nonpreservation group). The 3-year, 5-year, and 7-year BCR-free survival rates were 79.2%, 75.3%, and 70.2%, respectively. In conclusion, the incidence of PSM in pT3 was decreased significantly after 250 cases. There was a trend in the surgical learning curve for decreasing PSM with each group of 50 cases. NVB preservation during RALP for the high-risk group is not suggested due to increasing PSM.

Pathological analysis of lymph nodes in anterior prostatic fat excised at robot-assisted radical prostatectomy

Aims

To assess the lymph node content of anterior prostatic fat (APF) sent routinely at robot-assisted laparoscopic radical prostatectomy (RALP) and the incidence of positive nodes in the extended pelvic lymph node dissection.

Methods

Between September 2008 and April 2012, APF excised from 282 patients who underwent RALP was sent for pathological analysis. This tissue was completely embedded and lymph nodes counted.

Results

In total, 49/282 (17%) patients had lymph nodes in the APF, median lymph node yield in this tissue was 1 (range 1–5). In four patients, the lymph nodes contained metastatic deposits. These patients did not have positive nodes elsewhere in the extended lymph node dissection.

Conclusions

APF contains lymph nodes in 1 in 6 patients and infrequently these may be malignant. APF should always be removed at radical prostatectomy. APF should be routinely sent for pathological analysis.