Pelvic lymph node dissection (PLND) is an important component of the surgical management of prostate cancer, particularly for patients with high-risk features ( ). At the time of radical prostatectomy (RP), PLND provides accurate staging information that will guide postsurgical follow-up and the selection of either adjuvant or salvage treatment, including clinical trials. PLND may also have a therapeutic benefit by eliminating small metastatic foci, which might otherwise disseminate systemically (Heidenrich 2002, , , ).
Stage migration and decreased lymph node involvement (LNI), which is currently assessed with the aid of predictive models ( ), have also led to a declining trend in the use of concurrent PLND at the time of RP ( , , ). Nonetheless, because of the lack of adequate preoperative imaging techniques, PLND during RP remains the gold standard staging procedure to assess anatomically for the presence of early metastatic disease ( ).
The role of PLND for prostate cancer outcomes remains controversial ( ). Prostate cancer screening and the increased use of prostate-specific antigen (PSA) testing resulted in a stage migration with more patients with organ-confined disease and a corresponding decrease in lymph node involvement (LNI) ( , ). This resulted in many urologists either not performing a PLND during RP or reducing the anatomic limits of the PLND ( ). However, because of the increasing frequency of managing low-risk prostate cancer with active surveillance, most men treated surgically today are recommended to have a PLND, especially men with intermediate- or high-risk cancers. Although randomized data demonstrating a therapeutic benefit to PLND are lacking, reports showed a better biochemical recurrence (BCR)–free survival with an increasing number of lymph nodes (LNs) removed in node-negative patients and in patients with low volume of metastatic LN who underwent RP and PLND ( , , , ).
Unfortunately, standard preoperative imaging, such as computed tomography or magnetic resonance imaging (MRI), has not proven accurate in identifying men with or without nodal metastases and thus cannot be used to select which men undergoing an RP should or should not have a PLND ( , ). Emerging new imaging modalities are still experimental ( , ). As such, PLND remains the most accurate staging method to determine nodal status in prostate cancer.
The identification of the optimal candidate for PLND is performed using preoperative nomograms designed to assess the risk of positive pelvic lymph nodes according to prostate cancer features. To prevent the risk of underestimating the presence of nodal metastases, nomograms based on standard or extended PLND series ( , ) are to be preferred over nomograms based on limited PLND series ( , ).
There is no consensus among various medical organizations regarding the selection of men for PLND. The American Urological Association recommends PLND for patients at “higher risk of nodal involvement” ( ); the National Comprehensive Cancer Network recommends PLND in patients with a ≥2% risk of nodal involvement by nomograms ( ); and the European Association of Urology, based on recently updated nomograms, recommends PLND in all men with intermediate- and high-risk prostate cancer ( ).
Pelvic lymph nodes have been somewhat arbitrarily divided into external iliac, obturator, and hypogastric areas. The frequency and distribution of pelvic LN metastases based on these three anatomic locations was evaluated in a consecutive series of 642 contemporary American patients with clinically localized prostate cancer treated with RP by a single surgeon between 2002 and 2009. LN metastases were found in 8.2%, including 1.7% with low, 8.6% with intermediate, and 23.9% with high risk cancer. A median of 16 (interquartile range [IQR] 11–22) LNs was removed. The majority (69%) of patients with nodal metastases had positive LNs in only one of the three anatomic areas (11% in the external iliac, 26% in the obturator, and 31% in the hypogastric area). LN metastases were found more often and frequently exclusively in the obturator (60%) and hypogastric (49%) areas than in the external iliac area (37%). Of note, a single LN or two positive LNs were found in 49% and 31% of patients with positive nodes, respectively. These data confirm that a PLND limited to the external iliac area, while performed by many urologists, is an inadequate dissection. A PLND dissection limited to this area would identify and remove lymph node metastases in only a third of the patients who actually harbored positive pelvic nodes ( ). As such, the recommended PLND includes removal of node-bearing tissue from the external iliac, obturator, and hypogastric areas. These anatomic limits define the standard PLND ( Fig. 78.1 ) ( ). This standard dissection yields more total and identifies more positive nodes than a more limited dissection ( , , , ).
Minimal Number of LNs for an Adequate PLND
A wider anatomic template of PLND results in higher nodal yields, allowing for a better detection of metastasis ( , , ). Factors influencing the total number of LN removed during PLND include the surgeon and the surgical technique, the pathologists and tissue processing technique, the patient characteristics, and the audit effect and feedback to the surgeons about the number of nodes removed ( ). However, no consensus has been obtained on the minimal number of LNs above which the PLND may be considered adequate ( ).
Higher BCR-free survival was found in node-negative patients undergoing a more extensive PLND during RP, suggesting that a more extensive PLND might have a therapeutic benefit by removing micrometastases that were not identified by routine histologic examination ( ). A retrospective analysis was performed on 614 pT2-4N0 patients who underwent limited (1–9 LNs removed) versus extended (≥10 LN removed) PLND. The mean follow-up time was 62.5 ± 39.7 months. BCR was defined as PSA ≥0.2 ng/mL. Five- and 10-year cancer-specific survival rates of 98.8% and 95.8%, respectively, and BCR-free survival rates of 77.2% and 60.7%, respectively, were observed. BCR occurred in 21.2% of patients. A higher number of LNs removed predicted a slightly lower risk of BCR (hazard ratio [HR] = 0.926, 95% confidence interval [CI] 0.932–0.992 per each additional LN removed; p = .013). Patients who received an extended PLND had a significantly lower risk of BCR compared to patients who received limited PLND (HR = 0.658, 95% CI: 0.464–0.934, p = 0.019). Multivariate analysis showed independent and significant correlations between LN group, PSA, clinical and pathologic Gleason score (GC), pathological stage and adjuvant radiotherapy and BCR.
Comparing PLND outcomes in patients at risk for LNI who were undergoing RP by different surgeons and surgical approaches, including open, laparoscopic, and robot-assisted laparoscopic prostatectomy (RALP), the individual surgeon commitment to PLND was found to be more important than the surgical approach because standard PLND, including external iliac, obturator, and hypogastric nodal packets, could be performed by any surgical approach with slightly different yields but similar pathologic outcomes ( ). Using multivariable linear regression with adjustment for clinical stage, biopsy Gleason score, PSA level, and age in patients who underwent RP with standard PLND for a ≥2% predicted risk of LNI, significantly more nodes were removed by open and laparoscopic (median 20 and 19, respectively) than RALP (median 16). After adjusting for nomogram probability of LNI, however, no difference was detected between approaches in rates of LNI. For all three approaches, variation in median lymph node yield was significantly more considerable among individual surgeons (11–28) than the variability by approach.
Although the therapeutic benefit of PLND remains unproven, PSA remained undetectable 10 years after PLND and RP in 20%–56% of patients with positive nodes who received no additional therapy ( , , ). An actuarial 5-year probability of freedom from BCR recurrence of 50% was found in a recent analysis of 207 patients with positive nodes. The prognosis for patients with positive nodes is not uniformly poor. Those with low Gleason score (less than 8) cancer or few positive nodes (1 or 2) fare reasonably well ( , ). However, other studies did substantiate these findings ( , ). To date, there is an unmet need for Level 1 evidence supporting the value of PLND at the time of RP, including whether or not the extent of the PLND impacts patient outcomes. Despite this lack of data, as mentioned above, a standard PLND is recommended by most medical organizations in men with intermediate- and high-risk prostate cancer.
Patient Positioning, Surgical Incision, and Operative Technique
Open Standard PLND
The same instruments used for a retropubic RP are used. These include a GU major set, which includes a basic, a GU long, and a GU vascular set instruments; small and medium titanium clip appliers; long Debakey forceps; long Metzenbaum scissors; blunt-tip long right angle clamps; vein retractors; and long needle holders. In addition, an 18-French Foley catheter with a 5-mL balloon; water-soluble lubricant; a hand-controlled electrosurgery unit; and a suction device are needed. A retractor, that is, a Turner-Warwick retractor is used to provide exposure and in most circumstances the entire PLND can be performed using only five retractor blades, including two malleable blades used to be placed in the retroperitoneal pockets created underneath the cord structures, two C-shaped blades to retract the caudal aspect of the incision bilaterally, and one malleable blade for retraction of the bladder medially.
The patient is positioned supine on the operating room (OR) table with the arms perpendicular to the body, and the anterior-superior iliac spine just above the break of the table. Adjustments may be needed according to the patient’s height. Sequential pneumatic compression devices are used throughout the procedure. General anesthesia is induced. The OR table is slightly flexed and placed in Trendelenburg position to make the suprapubic area level. Chlorhexidine gluconate and isopropyl alcohol is used for sterile preoperative abdominal skin preparation. Povidone-iodine solution is used for the preparation of the genital and inguinal areas with extension to the bilateral upper thigh. After a standard draping including a sterile adhesive incise drape is placed, an 18-French urethral catheter is inserted using sterile technique and the balloon inflated with sterile water.
The intended midline incision line is marked from the pubic symphysis to the umbilicus before an approximately 8–10-cm skin incision is made using a no. 10 blade scalpel. Electrocautery is used through the subcutaneous fat that at the caudal end of the incision is taken down to the level of and approximately 2 cm beyond the pubic bone. Skin flaps are developed bilaterally to expose the rectus abdominis fascia for easier identification and closure at the completion of RP. The anterior laminae of the rectus abdominis fascia is opened in the midline using electrocautery and the fascial incision extended caudally and cranially along the linea alba. The bilateral rectus abdominis muscle is mobilized with care being taken to prevent injury to the inferior epigastric artery and vein bilaterally. The rectus abdominis muscles are retracted laterally and the incision extended caudally through the piramidalis muscles using electrocautery. The fascia transversalis is incised with electrocautery up to the superior aspect of the incision.
A plane is bluntly developed by sweeping the surgeon’s fingers or gently using a sponge stick between the bladder and the peritoneum medially and the adipose tissue surrounding the iliac vessel and containing the pelvic LNs laterally on each side to expose the space of Retzius ( Fig. 78.2 ). The surgeon’s fingers are placed near the endopelvic fascia and swept along the pubis following the course of the external iliac vessels. This step has to be performed gently to prevent disruption of the obturator nodal packet. Under the bilateral cord structures, a retroperitoneal pocket is developed to accommodate the placement of a blade of the retractor, that is, a Turner-Warwick retractor for cephalad retraction of the spermatic cord and the peritoneum. The vas palpated superiorly and the obliterated umbilical artery medially confirms the proper location and depth of the retroperitoneal pocket.
The retractor’s blades are placed using moist-tipped laparotomy sponges to protect the abdominal wall structures and the peritoneum from injury. The retractor’s blades, which will remain in the same position for the remainder of the procedure, should cause no traction on the iliac vessels and their branches, which should in fact all remain in their anatomic position. Two small C-shaped blades are then placed bilaterally at the caudal aspect of the incision to enhance exposure. Finally, a malleable blade will be used to retract the bladder away from each PLND side and provide adequate countertraction.
The primary surgeon uses Debakey forceps and blunt-tipped Metzenbaum scissors while the primary assistant uses a handheld vein retractor and a surgical aspirator. The nodal tissue just inferior to the external iliac vein is gently pulled medially with forceps, and a window between the inferior aspect of the external iliac vein and the pelvic sidewall is created using the scissors ( Fig. 78.3 ) to accommodate the vein retractor ( Fig. 78.4 ). The window underneath the external iliac vein is developed cranially and caudally to gain full access to and harvest LNs from the external iliac area, which extends from the external iliac vein to the obturator nerve and from the bifurcation of the common iliac vessels to the pelvic floor at the Cooper ligament, including the ilio-inguinal LNs ( Fig. 78.5 ). Using Metzenbaum scissors and a blunt-tip right angle clamp, the Cooper ligament is cleared off of LN tissue, which is ligated using a 2-0 silk tie or clipped to prevent lymphocele formation. Vascular structures behind and inferior to the LN packet should be preserved. The removal of the Cloquet node, which may be used as a distal landmark, is not always indicated ( , , ). Care should be taken to avoid the circumflex vein, which is distal. The lymphatic tissue superior to the middle portion of the external iliac vein should be preserved as it constitutes the primary lymphatic drainage for the ipsilateral lower limb.
Next, the obturator nerve is identified within the obturator fossa and skeletonized and cleaned of nodal tissue using a split and roll technique. The obturator artery and vein are identified and preferentially spared, whereas small vessels might be clipped and cut if deemed necessary. Using Singley tissue forceps, additional nodal tissue is harvested from the obturator area, which is deep to the obturator nerve, medial to the obturator vessels, and extends to the endopelvic fascia caudal and to the bladder wall medial. The removal of the LN packet has to be performed gently to minimize vascular injuries that might be difficult to control because of the depth of the pelvis. Resistance, when encountered, may indicate the presence of small perforating vessels. The nodal packet is then retracted superiorly and medially and the dissection carried posteriorly toward the internal iliac artery and the bifurcation of the common iliac vein. Remaining lymphatic channels and fibrofatty tissue holding the packet are clipped and transected.
The standard PLND is completed by harvesting LN tissue from the hypogastric area that, also located below the obturator nerve, is more cephalad, extending from the hypogastric artery and vein superior, and along the psoas muscle lateral to the obturator vessels, including tissue among small branches of the hypogastric artery up to its origin at common iliac artery bifurcation ( Fig. 78.6 ). The nodal packet is cleared down to the level of the offtake of the obturator artery posteriorly and the offtake of the medial umbilical ligament. This is performed using two Singley tissue forceps in “hand-over-hand” fashion maintaining the bifurcation of the common iliac vessels always in view and avoiding any injury to the sciatic nerve, which marks the deep or dorsal border of the obturator and hypogastric areas.
Hemostasis is verified. Small surgical clips may be applied and hemostatic agents, that is, oxidized cellulose polymers placed in the gutter lateral to the obturator nerve as needed. The lymphatic tissue obtained from the external iliac, obturator, and hypogastric areas is sent for histologic examination. In similar fashion, the PLND is performed contralaterally before proceeding with RP.
Robot-Assisted Standard PLND
Detailed knowledge of the regional anatomy, high degree of comfort and skill in the use of the robotic platform, ability to achieve and maintain adequate exposure, and proper use of traction and countertraction are keys to a successful robot-assisted PLND ( Fig. 78.7 ). The boundaries for performance of a robot-assisted standard PLND replicate those of the open standard PLND.
The same instruments used for an open PLND should be available in case an open conversion is indicated. Also, a Veress needle; laparoscopic insufflation tubing; robotic instruments including a 0° lens or a 30° lens, or both, robotic laparoscope, scissors, a Maryland or fenestrated bipolar forceps, Prograsp forceps, Hem-o-Lock clip appliers; a laparoscopic suction-irrigation device; laparoscopic graspers; and laparoscopic spoon forceps are needed. A smoke evacuation system, a laparoscopic specimen collection bag, and hemostatic agents such as oxidized cellulose polymers and topical hemostatic sealants may be helpful. An 18-French Foley catheter with a 5-mL balloon, water-soluble lubricant, and a hand-controlled electrosurgery unit are needed as well.
The patient is positioned supine on the operating room (OR) table provided with an egg crate or other nonslipping surface, which will prevent the patient from sliding towards the head of the table when it will be placed in steep Trendelenburg. Sequential pneumatic compression devices are placed to be used throughout the procedure. General anesthesia is induced and the patient is secured to the OR table with both arms tucked to the side. Older robotic platforms require the patient’s leg to be placed in lithotomy position, whereas newer platforms are able to operate with the patient in supine position. Prior to begining preoperative abdominal skin preparation with chlorhexidine gluconate and isopropyl alcohol, the OR table should be temporarily tilted in steep Trendelenburg position to verify absence of patient’s sliding. Povidone-iodine solution is used for the preparation of the genital and inguinal areas with extension to the bilateral upper thigh. Standard draping including a sterile adhesive incise drape is placed. An orogastrict tube and an 18-French urethral catheter is inserted using sterile technique, with the balloon inflated with 15 mL of sterile water.
The intraperitoneal laparoscopic access is described herein because it is the most commonly used. However, the results of extraperitoneal and intraperitoneal laparoscopic access are similar. Access to the abdominal cavity may be achieved with a Veress needle introduced through the abdominal wall after a 10- to 12-mm supraumbilical semicircular incision is made. The needle is aspirated and a drop test is performed to confirm the intraperitoneal location of the needle. The insufflation tubing is connected, insufflation is started at low flow, for example, 3 L/min, and the opening pressure, which should be less than 5 mm Hg, is monitored to prevent subcutaneous emphysema or insufflation of the preperitoneal space. A pneumoperitoneum of 15 mm Hg is created and the Veress needle is replaced with the camera port (8 mm with newer platforms, 12 mm with older systems). The robotic camera is inserted and the abdominal cavity inspected to rule out vascular or bowel injuries and to assess relevant anatomy, including the possible presence of adhesions.
Three additional robotic ports, for example, two for robotic arms on the patient’s right and one on the left for a right-handed surgeon, are placed under direct vision almost equally spaced 8.5–10 cm apart at or above the level of the umbilicus. The table assistant is provided with a 12-mm lateral assistant port inserted 3–4 cm superomedial to the left iliac crest, and a 5-mm port placed in between the camera port and the left-sided at least 5 cm cephalad to the line connecting the two trocars ( Fig. 78.8 ). The OR table is placed in steep Trendelenburg position to allow the bowel segments to fall away from the pelvis, and the robotic arms are docked. Monopolar scissors are inserted on the right side using the number-one robotic port; a Maryland or fenestrated bipolar forceps in the left hand; a Prograsp forceps in the third arm on the far right; and the suction-irrigation device tip and a small bowel grasper through the 5- and 12-mm ports, respectively, to be used by the surgeon’s assistant ( Fig. 78.9 ). Based on surgeon’s preference, a 30° down or a 0° lens may be used for the PLND. Large lymphatic channels may be controlled using 5-mm Hem-o-Lock clips ( Fig. 78.10 ) or a robotic vessel sealer.