Lymphadenectomy After a Positive SLNB in Melanoma

The treatment paradigm for melanoma patients with a positive SLN:
- Has undergone a dramatic evolution in recent years
  - Historically, completion lymph node dissection (CLND) was considered the standard of care for patients found to have micrometastatic disease in the SLN:
    - However, two recent trials sought to investigate the efficacy of immediate CLND:
      - The DECOG-SLT and MSLT-II trials were multicenter randomized control trials:
        
        That randomly assigned melanoma patients with sentinel-node metastasis to either immediate CLND versus observation by nodal ultrasound
  - In the DECOG-SLT trial:
    - 477 patients were enrolled
    - At three years, the study reported no difference in distant metastasis-free survival:
      - 77% versus 74.9%, HR 1.03; p=0.87 between the observation group and CLND group
    - At three years, the study reported no difference in overall survival:
      - 81.7% versus 81.2%, HR 0.96; p=0.87 between the observation group and CLND group
  - Similarly, in the larger MSLT-II trial:
  - Where 1,755 patients were evaluated
  - The study found that immediate CLND did not improve melanoma-specific survival when compared to patients that underwent observation:
    - 86% versus 86%; p=0.42
If, however, patients are unable or unwilling to undergo close surveillance:
- Completion lymph node dissection can be considered
Completion lymph node dissection for microscopic inguinofemoral SLN involvement consists of:
- Superficial groin dissection:
  - Which includes clearance of nodal tissue within the femoral triangle
- These nodes are accessed via either an oblique incision below or a lazy incision crossing through the inguinal crease:
  - Flaps are made superiorly several centimeters above the inguinal ligament, laterally to the anterior superior iliac spine (ASIS) and proceeding along the lateral border of the sartorius to the apex of the femoral triangle, and medially along the adductor longus to the pubic symphisis:
    - All nodal tissue within these landmarks and around the femoral vessels is taken:
      - With effort to preserve the lateral femoral cutaneous nerve:
        
        As it runs below the ASIS and superior to the sartorius
- The saphenous vein may be sacrificed if gross nodal disease precludes safe dissection of nodal tissue circumferentially:
  - However, preservation can be performed with theoretical benefits in preventing lymphedema
- Depending on the extent of tissue resection and the health of overlying skin, a sartorius transposition flap can be made to cover the femoral vessels
Several centers advocate intraoperative assessment by frozen section of Cloquet’s node:
- The lowest iliac node located within the femoral canal:
  - To determine whether immediate or delayed deep (iliac/obturator) node dissection is warranted:
    - However, the clinical adaptation of this technique is variable:
      - Sole excision of Cloquet’s node without further superficial inguinal node dissection is not standard of care
References:
- Al-Refaie WB, Ross MI. Inguinal lymphadenectomy for malignant melanoma. Operative Techniques in General Surgery, 2006. WB Saunders, Philadelphia, PA.
- Faries MB, Thompson JF, Cochran AJ, et al: Completion Dissection or Observation for Sentinel-Node Metastasis in Melanoma. N Engl J Med 376:2211-2222, 2017
- Leiter U, Stadler R, Mauch C, et al: Complete lymph node dissection versus no dissection in patients with sentinel lymph node biopsy positive melanoma (DeCOG-SLT): a multicentre, randomised, phase 3 trial. Lancet Oncol 17:757-767, 2016
- Essner R, Scheri R, Kavanagh M, et al. Surgical management of the groin lymph nodes in melanoma in the era of sentinel node dissection. Arch Surg. 2006;141:877-882.
- Jacobs LK, Balch CM, Coit DG. Inguinofemoral iliac/obturator, and popliteal lymphadenectomy in patients with melanoma. In: Balch CM, Houghton AN, Sober AJ, Soong S-J (eds.) Cutaneous Melanoma. 5th ed. St. Louis: Quality Medical Publishing; 2009:457-470.
- Tsao H, Atkins M, Sober AJ. Management of cutaneous melanoma. N Engl J Med. 2004;998-1012.