Optimizing Nodal Staging in Intermediate and High-Risk Prostate Cancer: An Examination of Sentinel Lymph Node Dissection Using ICG/NIR

Abstract

This study evaluated the use of sentinel lymph node (SLN) dissection with indocyanine green/near-infrared (ICG/NIR) technology in laparoscopic radical prostatectomy for clinically localized prostate cancer (PCa). Conducted from 2020 to 2023, the study included 60 patients: 45 at intermediate or high risk underwent both SLN dissection and extended pelvic lymph node dissection (ePLND), while 15 low-risk patients had SLN dissection only. Sentinel nodes were identified in over 90% of cases. Body mass index (BMI) was found to influence the time taken to locate SLNs. Among intermediate and high-risk patients, 22% showed metastatic involvement. The procedure demonstrated a specificity of 90%, sensitivity of 80%, and positive predictive value of 95,7%. The study concludes that SLN dissection is a feasible and effective method for preoperative nodal staging in PCa, although further research is needed for optimization.

1. Introduction

Introduced in the late twentieth century, sentinel lymph node biopsy (SLNB) has become a pivotal diagnostic and therapeutic instrument in oncology. It aims to pinpoint the first lymph nodes potentially affected by tumor metastasis, assisting in disease staging and shaping treatment choices. The principle behind SLNB is that if the sentinel node, being the first to encounter migrating cancer cells, test negative, a more invasive standard lymph node dissection may not be required. Currently, there is increasing evidence supporting the utility of SLNB as a predictive and therapeutic tool, with varying outcomes depending on the tumor location [1, 2].

One of the earliest studies focusing on sentinel lymph nodes was conducted in 1977 when Cabanas R.M. hypothesized that the sentinel lymph node could be the initial node affected during the progression of penile cancer (PeCa). Given its unique lymphatic spread patterns—where distant metastases rarely manifest without preceding involvement of the inguinal LNs—PeCa has subsequently been recognized as a promising candidate for extended SLNB investigation [3]. As a result, the EAU-ASCO Penile Cancer Guidelines recommend SLNB for T1b or higher PeCa patients [4].

Like in PeCa, SLNB’s application in melanoma and breast cancer has shown promising results in clinical practice. In 1992, Morton et al. introduced SLNB for early-stage melanoma, later validating its accuracy in predicting regional node metastasis and establishing its prognostic significance for primary skin melanoma, stage T2–T3 [5, 6]. Similarly, in 1993, Krag et al. utilized radiolabeled colloid to identify sentinel nodes in breast cancer, marking a transformative shift in breast cancer management where sentinel lymph node biopsy (SLNB) gradually replaced routine axillary lymph node dissection due to its lower morbidity [7, 8].

Encouraging evidence for the potential use of the sentinel lymph node concept in the treatment of PeCa, melanoma, and breast cancer has led to intensive research in other areas of oncological surgery. In gynecologic cancers such as endometrial, cervical, and vulvar, emerging research suggests the potential of sentinel lymph node staging as an alternative to traditional lymphadenectomy [9, 10, 11, 12, 13]. SLNB shows promise for early-stage oropharyngeal squamous cell carcinoma for head and neck cancers but is less established for melanoma due to complex lymphatic drainage patterns [14, 15]. The role of SLNB in other cancers, including gastric, colorectal, and lung, is still being assessed, but preliminary findings suggest potential clinical benefits [16, 17, 18].

In urological malignancies such as kidney and bladder cancers, the significance of SLNB remains ambiguous. The EAU-ASCO Guidelines underscore SLNB as a promising avenue, particularly in the imaging context for muscle-invasive bladder cancer [2, 19]. For prostate cancer (PCa), SLNB is referenced in the guidelines as a research-focused staging method, but it currently lacks robust evidence confirming its efficacy [20].

As with many cancers, the decision to undertake lymph node dissection in the treatment of intermediate and high-risk patients is often met with uncertainty, and this holds true for PCa as well. Despite the widespread use of extended pelvic lymph node dissection (ePLND), a significant proportion of patients undergo this procedure unnecessarily, as evidenced by the absence of metastatic lymph nodes in the final pathology reports [21]. In this context, sentinel lymph node (SLN) dissection could serve as a valuable screening tool to distinguish patients who would benefit from ePLND from those who could safely avoid it. While SLNB in PCa shows promise, the evidence supporting its use is not as robust as for penile, breast cancer, or melanoma. More clinical data need to be collected to solidify its role in prostate cancer management.

The study aims to evaluate the technical details and efficacy of sentinel lymph node (SLN) dissection during laparoscopic radical prostatectomy in patients with clinically localized PCa, using indocyanine green/near-infrared (ICG/NIR) technology.

2. Material and methods

Between 2020 and 2023, a prospective study was conducted on 60 patients diagnosed with PCa, as confirmed by prostate biopsy, contrast-enhanced computerized tomography (CT) scans, bone scans. Verification of the affected areas of prostate was conducted using multiparametric magnetic resonance imaging (mpMRI) of the prostate gland prior to biopsy. Inclusion criteria for the study were clinically diagnosed and histologically confirmed localized prostate cancer, subjected to radical prostatectomy (Table 1). Patients with imaging confirmed lymphadenopathy, history of prostatitis, transurethral resection of prostate (TURP) due to benign prostatic hyperplasia (BPH), previous hormonal treatment were excluded from the study. Written informed consent was obtained from all patients in accordance with the Declaration of Helsinki. The local ethics committee was informed of this investigation.

Index	Overall (n = 60)	pN0 (n = 47)	pN1 (n = 13)
Age at diagnosis, years, median (IQR)	65.0 (60.75;69.0)	67.0 (62.0;69.0)	62 (59.0;65.0)
PSA, ng/ml, median (IQR)	12.05 (8.04;19.25)	10.6 (7.42;16.36)	15.33 (11.7;32.0)
BMI, kg/m^2 median (IQR)	27.34 (25.43;29.56)	26.89 (25.26; 29.26)	28.73 (26.12; 30.89)
Prostate volume, cm^3, median (IQR)	41.0 (34.0; 57.4)	38.0 (33.0;57.0)	52.0(40.0;57.0)
Risk group (No. pts., %):
Low	15 (25%)	15 (32%)	0 (0%)
Intermediate	29 (49%)	25 (52%)	5 (38%)
High	16 (26%)	8 (16%)	8 (62%)
No. removed SLNs/ Mean ± SD
Overall	160	151	39
Left side	81/1.3 ± 0.8	63/1.3 ± 0.7	18/1.2 ± 0.6
Right side	79/1.3 ± 0.7	58/1.3 ± 1.0	21/1.6 ± 0.6
No. removed LNs/ Mean ± SD
Left side	223/9.7 ± 2.6	149/4.7 ± 2.7	74/4.9 ± 1.9
Right side	243/10.6 ± 2.3	158/5.7 ± 2.3	85/6.5 ± 2.4
%ISUP grade(No. pts):
1	9 (15%)	9 (19%)	-
2	28 (47%)	24 (51%)	4 (31%)
3	10 (17%)	6 (13%)	4 (31%)
4–5	13 (21%)	8 (17%)	5 (38%)
% T stage (No. pts):
2	18 (30%)	13 (34%)	6 (55%)
3a	15 (25%)	22 (56%)	4 (36%)
3b	27 (45%)	4 (10%)	1 (9%)

Table 1.

Patient parameters and pathological outcomes.

All patients underwent laparoscopic radical prostatectomy supplemented with SLNs dissection, followed by standard ePLND in 45 patients with intermediate and high-risk PCa. The remaining 15 patients, who had clinically localized low-risk PCa, underwent only sentinel lymph node dissection.

To achieve ICG/NIR technology, we used Verdye (25 mg) Indocyanine green, Diagnostic Green, IMAGE1 S™ 4 K Rubina™ KARL STORZ equipment. The procedure of intraprostatic ICG injection was performed in the operating room just before the surgery began.

The patient was positioned in the lithotomy position. ICG was reconstituted immediately prior to use. To prepare the solution, 10 ml of sterile water was injected into the vial containing 25 mg of ICG powder, resulting in a concentration of 2.5 mg/ml. The vial was gently swirled until the ICG was completely dissolved, which typically takes 3–4 min. After the induction of general anesthesia, intraprostatic injection of indocyanine green (ICG) solution 2.5 mg/mL was performed using a Chiba needle 22 g under the guidance of a transrectal ultrasound, utilizing MRI-guided cognitive fusion of the lesions.

ICG solution was injected into the area of the MRI-identified tumor and sextant biopsy areas of the prostate (2.5 mL per lobe). Immediately following the injection, the patient was repositioned into a standard supine position for the radical prostatectomy. The positioning of the patient and trocar set-up were standard for a transperitoneal laparoscopic prostatectomy. Using the 25 to 30-degree Trendelenburg position, intestinal loops are moved cranially to expose the field of the common iliac vessels where lymph node luminescence is supposed to be determined [22]. An incision of the peritoneum along the iliac vessels is performed. After excision of fluorescent lymph nodes on the right and left side, the ePLND was performed in the patient with indications, followed by radical prostatectomy. All surgical procedures were performed by the same expert senior surgeon.

Patient demographic data, body mass index (BMI), pre-operative prostate-specific antigen (PSA) were collected for all participants. Decision for radical prostatectomy and ePLND was based on PSA, MRI, CT, and bone scan data. Tumor characteristics and staging were assessed through routine postoperative histopathological examination.

2.1 Data analysis

Descriptive statistics were calculated for all clinical characteristics. Continuous variables were reported as medians (interquartile range), and categorical variables as frequencies (percentage). Multiple linear regression was employed to model the relationship between characteristics of interest. Two-sided p-values were reported for all statistical tests. The likelihood of differences in categorical data was assessed using Pearson’s Chi-square test (χ2), while quantitative and ordinal data were evaluated using the Mann-Whitney U test. The critical value for the level of statistical significance (p) was set at less than 5% (p < 0.05) for all types of analyses. Statistical analysis was performed using R version 3.5.1.

3. Results

3.1 Identification of sentinel lymph nodes

Upon completion of the ICG injection, patients were positioned in a standard supine position, and the surgical field and instruments were subsequently prepared. The incision and insertion of the first trocar took place, on average, 8–10 minutes following the ICG injection. After inserting the trocars and instruments, the abdominal cavity was examined using a near-infrared filter (Figure 1).

Figure 1.

Visualization of lymph node luminescence. 1 – Fluorescent lymph node, 2 – Right external iliac artery, 3 – Intestinal loop.

It was observed that the fluorescence of the lymph nodes was most commonly situated in the area of the bifurcation of the common iliac artery. This could be clearly seen after cranial displacement of the iliac and sigmoid colon loops. A cut is made in the peritoneum along the iliac vessels, followed by meticulous “en bloc” removal of the fluorescence lymph nodes. To inhibit further ICG dissemination within the lymphatic system, surgical intervention commences at the cranial boundary of the dissection area and proceeds in a caudal direction. Adjacent lymphatic channels surrounding the node are sealed off, either through bipolar coagulation or using an ultrasonic scalpel (Figure 2). The dissection is finalized while avoiding direct handling or damage to the node tissue. Employing this approach mitigates the risk of ICG leakage, thereby preventing indiscriminate luminescence in the nearby tissue (Figure 3).

Figure 2.

Dissection of ICG+ lymph node. 1 – Fluorescent lymph node, 2 – Right external iliac artery, 3 – Lymphatic vessels.

Figure 3.

Dissection of fluorescent lymph node is finished. 1 – ICG leakage in surrounding tissue.

In 54 cases (90%) and 57 cases (95%), SLN fluorescence was identified in the area of the iliac vessels’ bifurcation, with minor variations of 1–1.5 cm in the medial and lateral directions for the right and left sides, respectively. In 4 cases (7%) for the right side and 2 cases (3%) for the left side, the SLNs were localized in the obturator fossa. In one case for both sides, the SLNs fluorescence was found in the area near the upper vesical artery and vein of the internal iliac vessels. In one case, fluorescence was not identified on the right side.

3.2 Time characteristics for lymphadenectomy in prostate cancer patients

The time characteristics for lymphadenectomy in patients with prostate cancer are outlined in Table 2. In all cases, lymphadenectomy was initiated on the right side and then transitioned to the left. On average, lymphadenectomy on the right side commenced 14.5 (8.0; 21) minutes after the start of the surgery, and on the left side, it commenced after 40.0 (31.0; 52.0) minutes. The mean time to locate sentinel nodes on the right side was 27.5 (23.5; 30.0) minutes; on the left, it was 46.5 (34.5; 52.5) minutes. The total duration for node removal based on extended lymph node dissection was 22.0 (15.0; 35.0) minutes on the right and 15.5 (13.0; 23.0) minutes on the left. The time specifically for SLNs was 6.0 (3.0; 9.0) minutes on the right and 4.0 (2.0; 6.0) minutes on the left. The minimum duration for sentinel node excision was 1 minute, and the maximum was 18 minutes.

Indicators	Node location	Right side	Left side	p-value
Time of initiation, min	Sentinel lymph nodes	14.5 (8.0; 21.0)	40.0 (31.0; 52.0)	NA
	Other lymph nodes	27.5 (23.5; 30.0)	46.5 (34.5; 52.5)	NA
Duration of lymph node removal procedure, min	Sentinel lymph nodes	6.0 (3.0; 9.0)	4.0 (2.0; 6.0)	0.161
	Other lymph nodes	14.0 (11.0; 25.0)	12.0 (9.0; 17.0)	0.300
Total, min		22.0 (15.0; 35.0)	15.5 (13.0; 23.0)	0.259

Table 2.

Average characteristics of time taken for lymphadenectomy in patients with prostate cancer, Me (25%; 75%).

The difference in duration for this stage of the operation based on the side of the node location was not statistically significant (p > 0.05), although there was a trend toward increased time for procedures on the right side due to anatomical complexities and concomitant pathological processes (adhesive process) in operated patients.

It was noted that the rate of SLN detection depended on several factors. The most significant factor was the presence of excess adipose tissue. In this patient group, initial visualization of the SLNs was not possible. These lymph nodes could only be identified after incision of the parietal peritoneum and dissection of the surrounding adipose tissue. When sentinel nodes were located in atypical areas (not in the area of the bifurcation of the common iliac artery), the time required for their identification increased.

We evaluate the impact of BMI on the process of localizing SLNs. It was found that the time taken to locate these nodes directly correlates with BMI: right side (r = 0.49, p = 0.029); left side (r = 0.47, p = 0.035) (Figure 4).

Figure 4.

Correlation between time to identify SLNs on the right (A) and left (B) sides and the patient’s BMI.

The average time to locate sentinel nodes on the right side from the start of the operation was 27.5 (23.5; 30.0) minutes. Specifically, with a normal BMI (up to 25 kg/m²), the time is 26.0 (16.0; 28.0); for overweight BMI (up to 30 kg/m²) - 29.0 (23.0; 33.0); and for obesity stage I (up to 35 kg/m²) - 29.0 (24.0; 39.0) minutes. The average time to locate nodes on the left side was 46.5 (32.5; 52.5) minutes. In terms of BMI: normal - 35.0 (26.0; 51.0), overweight - 47.0 (34.0; 52.0), and obesity stage I -54.0 (40.0; 69.0) minutes (Table 3).

BMI, kg/m^2	Time, min
	Right side	Left side
Normal (18.5–24.9)	26.0 (16.0; 28.0)	35.0 (26.0; 51.0)
Overweight (25–29.9)	29.0 (23.0; 33.0)*	47.0 (34.0; 52.0)*
Obesity Stage I (30–34.9)	29.0 (24.0; 39.0)*	54.0 (40.0; 69.0)*

Table 3.

Average time to locate SLNs from the start of surgery based on BMI, Me (25%; 75%).

*p < 0.05 compared to the normal range.

Unquestionably, BMI is a factor that technically complicates both open and laparoscopic surgical interventions. However, the influence of BMI on the process of SLN removal was statistically significant based on the collected data. Excessive body weight technically complicates and likely increases the time required to perform ePLND. Adhesion formation in the area adjacent to the aortic vessels led to the need for adhesiolysis, which also increased the time to visualize sentinel nodes. However, this factor is less significant than obesity, as it was infrequent—in 7 (11%) patients.

3.3 Pathohistological assessment

Identification and removal of SLNs were conducted in 60 patients. In 45 patients categorized as intermediate and high-risk according to the EAU risk group classification, extended lymphadenectomy was performed. A total of 160 SLNs were identified in these 60 patients, with 81 located on the left side and 79 on the right. In the 45 patients who underwent extended lymphadenectomy, 466 lymph nodes were removed: 223 on the left side and 243 on the right, with averages of 9.69 ± 2.61 and 10.56 ± 2.3, respectively.

Regional lymph node metastases were observed among the patients studied in 12 cases (12%), predominantly in those with pT3 stage disease. On the left side, the number of identified SLNs ranged from 0 to 3, averaging 1.35 ± 0.78. On the right, the range was from 0 (in 3 cases) to 3, with an average of 1.32 ± 0.65. There was no statistical difference between the two sides (p = 0.683).

Histological examination revealed no metastatic lymph node involvement in patients from the low-risk group where only SLNs were removed. In the remaining 45 patients, SLN involvement was found in 12 cases (22%) or in 17 out of the 160 removed SLNs (11%). Of these, 10 cases showed unilateral SLN involvement, while 2 exhibited bilateral involvement. In 4 of these 12 specific cases, isolated SLN involvement was observed, whereas in 8 cases, metastatic involvement had spread to other lymph nodes removed during extended lymphadenectomy. In one patient, a non-SLN showed involvement, but SLN involvement was not observed.

To evaluate the predictive capability of sentinel metastases for anticipating regional lymph node metastases, a chi-square test was conducted. The test revealed a specificity (Sp) of 90%, sensitivity (Se) of 80%, positive predictive value (PPV) of 61.5%, and negative predictive value (NPV) of 95.7%.

In our study, 5 patients (11%) experienced complications categorized as Clavien-Dindo Grade II. Specifically, these patients exhibited prolonged lymphorrhoea, necessitating an extended drainage duration without the need for additional procedures. Notably, these complications were observed exclusively in patients who underwent ePLND. Given these findings, the potential to reduce ePLND-associated complications by assessing SLN presents an appealing surgical option for patients with prostate cancer.

A concise overview of the study design and the results obtained is illustrated in Figure 5.

Figure 5.

Study design and obtained results.

4. Discussion

Our study focuses on exploring the capabilities of SLN biopsy exclusively using ICG technology. Currently, many studies for SLN verification employ magnetic and radioactive markers, each with its advantages and disadvantages, as well as their combined use with ICG [23]. Jeschke S. et al. found that ICG performed as well as 99mTc, and combining the two substances did not yield significantly better results than ICG alone. Utilizing the outlined fluorescence navigation method allows for real-time visualization of both lymph nodes and lymphatic vessels. This technique appears to offer comparable effectiveness to SLN dissection while being simpler to implement [22].

The procedure for injecting ICG into the prostate gland to identify SLNs is not standardized. Various methods for ICG injection have been described, including transrectal, transperineal, percutaneous intraoperative, and cystoscopic approaches. A study by Manny et al. compared these methods and found that robot-guided percutaneous ICG injection into the prostate was the most cost- and time-effective option [24]. Previously noted limitations of ultrasound in visualizing prostate lesions [25, 26, 27] have been overcome by combining it with MRI data. The use of MRI capability to visualize the zonal anatomy of the prostate and tumor foci, as described by the Prostate Imaging Reporting and Data System (PIRADS) version 2, has led to the fusion of MR images with real-time transrectal ultrasound to improve biopsy accuracy in diagnosing prostate cancer [28]. This technique has provided a more accurate solution for tracer injection into the affected zone of the prostate, thereby reducing the value of percutaneous ICG injection, which does not offer this capability. According to the FUTURE study, the existing three techniques—MRI-transrectal ultrasound (TRUS) fusion, cognitive registration, or in-bore MRI—have roughly equivalent diagnostic capabilities [29]. For preoperative use, the most cost- and time-effective option is the cognitive method, which we employed in our study.

In our study, we successfully employed transrectal injection of ICG, which was not accompanied by adverse side effects. By utilizing exclusion criteria such as a history of chronic prostatitis, which leads to prostate gland sclerosis, and prior transurethral resection of the prostate (TURP), the likelihood of ICG extravasation and inadequate distribution within the prostate tissue was reduced. Transrectal and transperineal tracer injections are currently being used [30, 31]. However, the preference is increasingly leaning toward the transperineal method under ultrasound guidance. This is because the needle is introduced parallel to the axis of the peripheral zone, allowing for the complete application of the tracer within this area without risk of extravasation. Additionally, this approach substantially reduces the risk of infection [32].

In the scientific literature, various methods of tracer injection into the prostate gland are described, primarily targeting the peripheral zone and focusing on the basal and apical portions, including the transitional zone. Buckle T et al. found that injecting ICG into the peripheral zone led to the visualization of a greater number of SLNs than injecting into the prostate’s central zone. This suggests that the location of intraprostatic tracer deposition may influence the preoperatively visualized lymphatic drainage [27].

Given the variability in tracer deposition, there is ongoing debate about whether to employ intraprostatic or intralesional tracer injections. Prostate cancer is generally a multifocal disease, predominantly originating in the peripheral zone. A recent randomized Phase II trial by Wit et al. revealed that intralesional injections were more effective in detecting lymph node metastases in the final pathology report. However, this technique failed to identify positive lymph nodes arising from diffuse or non-index prostatic lesions. Therefore, it is concluded that an optimal tracer administration strategy would likely involve a combination of both intraprostatic and intralesional approaches [33].

According to published data, the volume of ICG injected into the prostate gland varies, ranging from 0.1 to 1 mL per injection site, with concentrations varying from 0.1 to 1 mg/mL [27, 30, 32, 34]. There is currently no information favoring one approach over the others. From this perspective, reducing the concentration of the agent and increasing its volume aligns with the concept that the agent should be introduced not only into the areas of lesions identified by MRI but also into other parts of the prostate. Consequently, we chose the method proposed by Hruby et al., which involves the injection of a 0.1 mg/mL ICG solution at a volume of 2.5 mL per lobe, divided into 3 locations [32].

The time parameters of ICG distribution within the lymphatic drainage of the prostate gland remain poorly defined. According to published literature, ICG disperses relatively quickly—within 5 to 30 minutes—through the prostate’s lymphatic system due to the small molecular size of ICG [24, 32, 35, 36]. Therefore, precise identification of SLNs appears to be challenging. We monitored the timing of lymph node detection and excision, displaying luminescence features by sequentially performing the procedure first on the left side and then on the right. The time for the completion of the procedure varied within one hour from the moment of ICG injection to the start of surgical intervention. In this context, we found no significant differences in either the localization of the removed lymph nodes or their numbers, which were largely consistent with data reported by other authors [22, 36, 37].

The most significant factor influencing the speed of detection and removal of SLNs was the presence of obesity. This aligns with data from Stoffels et al., who demonstrated in a prospective study comparing ICG to 99mTc in melanoma patients that free-ICG has a tissue penetration depth of only 10–15 mm. This limits its ability to detect lymphatic structures that extend into deeper tissues, a limitation attributed to ICG’s inherently low fluorescence and the strong attenuation of low-energy NIRF in tissue [38].

The data we obtained regarding the predictive features of SLNB align with the broader picture presented by other authors for ICG technology and its combination with 99mTc-nanocolloid, as analyzed by Rossin et al. The “per patient” Se ranged from 75 to 100%, NPV from 93.8–100%, with false negatives (FN) at 0.0%, and false positives (FP) at 0.0%. On a “per node” basis, Se ranged from 34.1–100%, Sp from 64.8–99.0%, and NPV from 98.1–98.2% [23]. It is worth noting that these metrics could be influenced by the method of tracer injection into the prostate gland.

Time parameters can also impact the identification of sentinel nodes. The longer the time elapsed since the injection of ICG, the greater the likelihood of its spreading to lymph nodes of the second and third tiers. While this allows for better identification of the lymphatic drainage pathways from the prostate, it decreases the likelihood of accurately identifying SLNs. Based on ICG lymphography data, five main potential lymphatic pathways and sites can be distinguished: an internal route, a lateral route, a presacral route, a paravesical artery site, and a pre-prostatic site [30, 39].

Hruby et al. showed that the excision of ICG-positive lymph node groups resulted in increased Se (97.7%), NPV (99%), and accuracy (71%), while decreasing the false-negative rate (2%) when compared to extended and super-extended PLND. The use of fluorescence-guided pelvic lymph node dissection enhances the reliable identification of the prostate’s lymphatic drainage. Concentrating solely on nodes directly draining the prostate reduces the number of nodes excised, yet diagnostic precision is elevated. Additionally, this technique obviates the need to distinguish between initial receiving sites (sentinel nodes) and subsequent tiers, a task that can be challenging but is crucial in traditional sentinel node concepts [32].

5. Conclusions

The study suggests that SLN dissection is an effective, safe, and feasible approach for preoperative clinical nodal staging in prostate cancer patients, offering a viable approach for those with intermediate and high-risk PCa. Factors such as BMI were found to influence the time taken to locate the SLNs, which can affect the surgical process. The issue of accurately identifying SLNs for the prostate remains controversial and requires further research to clarify anatomical and temporal parameters of lymph node dissection.

Conflict of interest

The authors declare that they have no conflicts of interest.

This research has received no external funding.