Retroperitoneal Lymph Node Dissection

Classification of Retroperitoneal Lymph Node Dissection (RPLND)

• Primary RPLND
  • Performed after orchiectomy for CS I or low-volume CS II NSGCT with normal post-orchiectomy STMs
• Post-chemotherapy RPLND (PC-RPLND)
  • Performed after completion of induction systemic chemotherapy
  • Generally performed when there is a residual retroperitoneal mass and normal post-chemotherapy serum tumour markers. At some centers, PC-RPLND is performed even when there is a clinical complete remission (CR) to chemotherapy.
  • In general, patients with elevated STMs after induction chemotherapy should receive salvage chemotherapy.
    • Salvage PC-RPLND
      • Performed after completion of induction and salvage (standard or high-dose) chemotherapy.
    • Desperation PC-RPLND
      • Performed despite serum tumour marker elevation
    • Reoperative RPLND
      • Performed in a patient who has undergone prior primary RPLND or PC-RPLND
    • Resection of late relapse—PC-RPLND
      • Performed for retroperitoneal recurrence 24 months or later after CR to primary therapy (which may or may not have included RPLND).

Pre-operative planning

• Patients who are candidates for RPLND should be referred to an experienced surgeon at a high-volume center.
  • Surgeons with experience in the management of GCT and expertise in minimally invasive surgery may offer a minimally-invasive RPLND, acknowledging the lack of long-term data on oncologic outcomes with minimally-invasive approach.
• Principles of RPLND (template, limits, nerve-sparing, etc.) are applied, regardless of the intent to administer adjuvant chemotherapy or approach (open vs. minimally-invasive)
• Patients that have received bleomycin are at risk of post-operative respiratory distress syndrome; low fraction of inspired oxygen (FIO2) and conservative intraoperative fluid resuscitation are important in minimizing the risk of postoperative lung toxicity
  • Based on two studies, one from 1978 of 12 patients undergoing RPLND for testis cancer at MSK[1] (used t-test for statistics), and another from 1998 of 77 patients with previous bleomycin exposure undergoing “major surgical procedures” at MD Anderson[2]. The latter study found that in multivariate analysis, only amount of blood transfused, preoperative forced vital capacity and surgical time in descending order were significant. In univariate analysis, fluid balance, type of fluid given, among others were significant. Maintained intraoperative fractional inspired oxygen was not significant on either analysis.
• Identify renal arterial anatomy and possibility of accessory branches

Anatomic principles of RPLND[3]

• Template
  • Full bilateral template
    • The boundaries of a full bilateral template include
      • Superiorly: the crura of the diaphragm and skeletonized renal vessels
      • Inferiorly: the bifurcation of the common iliac arteries/crossing of the ureter over the ipsilateral common iliac artery
      • Laterally: the ureters
      • This area includes the primary and secondary landing zones of the right (paracaval, interaortocaval) and the left (paraaortic, preaortic) testicle.
    • A full, bilateral template includes removal of the (10):
      1. Para-aortic
      2. Retro-aortic
      3. Pre-aortic
      4. Left common iliac
      5. Interoartocaval
      6. Pre-caval
      7. Para-caval
      8. Retro-caval
      9. Right common iliac lymph nodes
      10. Ipsilateral gonadal vessels
    • Indications (2019 AUA Guidelines)[4]
      • Absolute (2):
        1. Suspicious lymph nodes based on CT imaging or intraoperative assessment
        2. Somatic-type malignancy in the primary tumor.
           • Malignant transformation of teratoma is defined as the transformation of a somatic teratomatous component of a germ cell tumor (GCT) to a nongerm cell malignant tumor[5]. Most common examples of malignant transformation are sarcoma (e.g., rhabdomyosarcoma, osteosarcoma, chondrosarcoma, angiosarcoma, and liposarcoma), carcinoma (adenocarcinoma and squamous cell carcinoma), primitive neuroectodermal tumor, as well as hematologic malignancies[6].
      • Relative
        • Clinically negative lymph nodes.
  • Modified
    • Right modified template may omit the para-aortic lymph nodes below the inferior mesenteric artery.
      • Omission of para-aortic lymph nodes above the inferior mesenteric artery is controversial.
    • Left modified template dissection may omit paracaval, precaval, and retrocaval lymph nodes.
      • Omission of interaortocaval lymph nodes is controversial.
    • Indications
      • Relative
        • Clinically negative lymph nodes.
  • A complete retroaortic and/or retrocaval lymph node dissection with division of lumbar vessels should be performed when within the planned template.
  • The ipsilateral gonadal vessels should be removed in all patients.

Open RPLND Technique

• Position: supine
• Incision: ventral midline
• Steps after incision:
  • When the peritoneal cavity is entered, a thorough inspection of abdominal viscera is performed.
  • The falciform ligament is identified, ligated, and divided to minimize risk of hepatic retraction injury.
  • A self-retaining retractor is then placed.
  • Exposure of the retroperitoneum
  • Split and role technique

Use of modified template RPLND

• The relatively predictable pattern of the lymphatic spread of testicular GCTs provided strong pathologic evidence for the use of “modified bilateral” templates in patients with low-stage retroperitoneal disease.
  • Omission of the contralateral retroperitoneum and interiliac regions resulted in the preservation of antegrade ejaculation in most patients.
  • Omission of suprahilar regions decreased the risk of postoperative chylous ascites, renovascular injuries, and pancreatic complications.
• The boundaries of the modified template vary by definition.
  • At Indiana, the recommended template for right‐sided tumours included the paracaval, precaval, inter‐aortocaval, pre‐aortic, right iliac and right gonadal regions. The template for left‐sided tumours included the para‐aortic, pre‐aortic, inter‐aortocaval, left iliac and left gonadal regions. Ultimately, Indiana’s modified templates eliminated dissection of the contralateral tissue below the inferior mesenteric artery, thereby sparing the lumbosacral sympathetic nerves, postsympathetic efferent nerves, and hypogastric sympathetic plexus.
• Suprahilar/retrocrural and interiliac resections can safely be omitted from the standard RPLND template. However, controversy exists regarding the need to resect the contralateral retroperitoneal lymphatic tissue.
• The standard PC-RPLND is resection of all macroscopic disease along with a full bilateral infrahilar dissection.

Nerve-sparing

• For successful antegrade ejaculation, several processes need to occur in coordinated fashion:
  1. Smooth muscle contraction in the vasa deferentia, seminal vesicles, and prostate resulting in seminal emission and prostate glandular secretion along
  2. Closure of the bladder neck to prevent retrograde ejaculation
  3. Rhythmic contractions of the ischiocavernosus, bulbospongiosus, and levator ani muscles expelling semen from the urethra.
  • Processes 1 and 2 (emission and closure of bladder neck) require efferent neurologic input from the L1 through L4 postganglionic sympathetic fibers, which coalesce with their contralateral counterparts in the superior hypogastric plexus. From the hypogastric plexus, these nerve fibers continue caudally to the seminal vesicles, ampulla of the vasa deferentia, vasa deferentia proper, bladder neck, and prostate
• Nerve-sparing Should be offered in select patients desiring preservation of ejaculatory function.
• Nerve-sparing RPLND results in preservation of antegrade ejaculation in 90-100% of patients
• Nerve-sparing should not compromise the quality of the lymph node dissection.

Minimally Invasive RPLND

• Rationale and Evolution
  • Potential advantages of MIS approach vs. open RPLND: decreased blood loss, shorter hospital stays, and faster return to normal activity
  • The abbreviated convalescence allows patients who are candidates to receive chemotherapy with minimal delay.
  • MIS approach can allow preservation of antegrade ejaculation in > 95% of patients, similar to nerve-sparing open RPLND
• Staging Laparoscopic RPLND and controversy
  • In all early series, L-RPLND was used as a staging procedure. Patients not harboring occult metastases were identified and spared exposure to chemotherapy without undergoing open RPLND. In this form, L-RPLND was performed without retrocaval or retroaortic dissection, and chemotherapy was given to all patients harboring metastatic disease (including patients with pN1 disease). The decision to omit dissection behind the great vessels was based on the belief of a lack of isolated positive lymph nodes in this area. Within this paradigm, the procedure was routinely aborted if positive lymph nodes were encountered, and chemotherapy was instituted in these cases. The use of restrictive template boundaries coupled with the universal use of chemotherapy in men harboring pathologic stage II disease generated criticism of published L-RPLND series. The controversy regarding the use of “staging” L-RPLND hinges on mapping studies demonstrating increased multifocality and contralateral disease in the presence of positive retroperitoneal nodes
  • In contemporary series, this approach has been abandoned, and L-RPLND has evolved into a therapeutic procedure duplicating the open approach (wide templates and complete excision of retroaortic and retrocaval tissue) in its intent
• Surgical technique
  • Indications for primary L-RPLND are identical to the indications for open RPLND and include clinical stage I or IIA disease, negative serum tumor markers, and the absence of comorbidities that would preclude safe surgery. In the post-chemotherapeutic setting, L-RPLND has been limited mainly to small-volume residual disease; however, experienced surgeons have excised bulky tumors
  • Preoperative patient preparation and technical considerations
    • All patients considered candidates for L-RPLND must be fully informed of all treatment options, including open RPLND, chemotherapy, and surveillance.
    • Potential complications include bleeding requiring blood transfusion; injury to adjacent organs (liver, bowel, gallbladder, kidney, ureter, pancreas, major vascular structures); and orthopedic, neurologic, or pulmonary complications as well as conversion to open surgery because of complications or incomplete resection
    • Patients interested in future fertility are educated regarding preoperative sperm banking
    • Patients undergo a mechanical bowel preparation the afternoon before surgery and take only clear liquids until midnight to decompress the bowels.
  • Approach
    • Most prefer a transperitoneal approach
  • Patient positioning and port placement for laparoscopic RPLND (details in Campbell’s)
    • Right-sided dissection
    • Left-side dissection
  • Bilateral laparoscopic RPLND
  • Robot-assisted RPLND port placement and technique
• Postoperative care
  • The patient may ambulate and resume a liquid diet the night of surgery.
  • Postoperative tachycardia may occur secondary to sympathetic stimulation
  • Most patients can be discharged on postoperative day 1.
• Prospective nerve-sparing techniques
  • As in open RPLND, nerve-sparing techniques involve prospectively identifying, dissecting, and preserving the sympathetic chains, hypogastric plexus, and postganglionic fibers. With experience, these tissues can be readily identified as more fibrous compared with lymphatic tissue.
  • On the right side, the postganglionic sympathetic fibers are most easily identified behind the IVC as they cross anterior to the aorta to insert in the hypogastric plexus. Their takeoff from the sympathetic chains is always near lumbar veins, so great care should be taken in clipping lumbar vessels.
  • On the left side, the postganglionic sympathetic fibers are most easily identified at the ganglia as they leave the sympathetic chain and dissect them prospectively as they course anterior to the aorta before joining the hypogastric plexus.
  • Care should be taken to avoid energy sources such as electrocautery when dissecting nerve fibers
• Complications
  • Postoperative complication rates of 9-25%
  • Potential complications include chylous ascites, ileus, lymphocele, nerve injury, pulmonary embolus, Clostridium difficile colitis, retroperitoneal hematoma, and ureteral injury
  • Intraoperative bleeding is still the most commonly reported complication of the laparoscopic RPLND
  • With meticulous ligation of lymphatic channels, the incidence of chylous ascites should be < 2%.
  • The rates of retrograde ejaculation have been consistently low with the laparoscopic approach and range from 0-14%
  • Open conversion rate is < 5%, but it has been reported as high as 11.8%; the most common reason for conversion to an open procedure is bleeding
  • Injury to major abdominal viscera also has been reported but appears to be a rare event
  • The morbidity and open conversion rate of L-RPLND after chemotherapy is higher
• Results and current status
  • Laparoscopic RPLND for clinical stage I disease
    • Published reports of L-RPLND with long-term follow-up suggest that it is an effective treatment option for patients with low-stage NSGCTs
    • Reports omitting chemotherapy for patients with N1 disease who underwent L-RPLND support its therapeutic efficacy, but more studies and follow-up are required
  • Laparoscopic RPLND for clinical stage II disease
    • Fewer reports exist examining the role of L-RPLND for patients with clinical stage II NSGCTs as a primary modality or in the postchemotherapeutic setting

Chylous ascites

• Refers to the accumulation of chylomicron containing lymphatic fluid in the peritoneal cavity.
• Occurs in 0.2-2% of patients undergoing primary RPLND and 2-7% of patients undergoing PC-RPLND
• Management options (5):
  1. Paracentesis
  2. Low-fat/medium-chain triglyceride diet
  3. Somatostatin/octreotide.
  4. Indwelling drain
  5. Total parenteral nutrition

Auxiliary procedures

• Nephrectomy is the most commonly performed auxiliary procedure at the time of PC-RPLND
  • Nephrectomy is usually needed in high-risk settings such as salvage RPLND, desperation RPLND, resection of late relapse, or reoperative RPLND.
• Inferior vena cava resection
  • Most cases requiring IVC resection have bulky stage disease (stage IIb or higher).
• Aortic resection and reconstruction
• Hepatic resections
• Pelvic resections

References

• Wein AJ, Kavoussi LR, Partin AW, Peters CA (eds): CAMPBELL-WALSH UROLOGY, ed 11. Philadelphia, Elsevier, 2015, chap 35
• Wein AJ, Kavoussi LR, Partin AW, Peters CA (eds): CAMPBELL-WALSH UROLOGY, ed 11. Philadelphia, Elsevier, 2015, chap 36
• Stephenson, Andrew, et al. "Diagnosis and treatment of early stage testicular cancer: AUA guideline." The Journal of urology 202.2 (2019): 272-281.
• Beveridge, Tyler S., et al. "Retroperitoneal lymph node dissection: anatomical and technical considerations from a cadaveric study." The Journal of urology 196.6 (2016): 1764-1771.[7]