Editing Melanoma (section)

== '''Managing the nodal basin''' (therapeutic dissection, SLNB, and completion dissection) ==

* If macroscopic nodal disease, confirm with FNA and stage with PET-CT and CT brain, CAP
* '''Therapeutic nodal dissection'''
** Indication: clinically-apparent nodal metastases which are subsequently confirmed on FNA
** Can be up-front or as salvage after SLNB/adjuvant therapy
** Remove all the fibrofatty and lymphatic tissue in the involved regional nodal basin, according to standard anatomic boundaries
** Locations
*** Axillary - levels I, II and III
*** Inguinal: superficial inguinal nodes, +/- pelvic nodes (internal iliac, external iliac and obturator nodes)
**** Indications for pelvic nodes: palpable deep nodal disease; imaging suggestive of pelvic nodal disease; metastasis to Cloquet node; gross involvement of multiple femoral nodes
*** Cervical nodes: functional neck dissection with sparing of IJV and spinal accessory nerve
* '''SLNB''' done when risk of having positive nodes is >5% and patients want it (may not be necessary with low life expectancy or comorbidities)
** Indicated for melanoma >1mm thickness, and for high-risk patients with melanoma >0.75mm thick (ulceration/mitotic rate >= 1 mitosis/mm<sup>2</sup>). Can also be considered in younger patients (higher risk of nodal disease and low-risk GA and surgery) and thickness 0.8-1mm.
*** Helps with staging
*** Guide systemic management
*** Perform at time of primary wide excision
** Controversial as to whether it is necessary in T4 disease, but Sabiston says should still do it
** If SNB is positive, still probably doesn't need complete lymph node dissection. Can probably use close surveillance and ultrasound for 5 years, if they seem reliable.
*** USS every 4 months for first 2 years, then 6 months for years 3-5
*** Biopsy any suspicious nodes identified. If cross-sectional imaging excludes other metastatic disease, then they should have a therapeutic dissection at that point.
** SLNB technique
*** Inject dye into the dermis at four points 0.5mm from the lesion (best to inject within margins of planned WLE)
*** Check for epitrochlear or popliteal nodes, in distal extremity lesions
*** All identified sentinel nodes should be removed
* '''Completion lymphadenectomy'''
** The procedure to remove the remaining lymph nodes in a regional basin after a positive SLNB
** Only offer when there is a high degree of concern for non-SLN metastases or inability to follow surveillance. The basis for this is two recent studies (DeCOG-SLT and MSLT-II) which showed not much difference between observation and dissection in terms of overall survival.
*** MSLT-I compared SLNB with observation of cN0 melanomas, and found that SLNB provided prognostic value and improved disease-free survival
*** MSLT-II randomised patients with positive SLNB to either immediate clearance or observation, and found no benefit to immediate clearance
** Potential advantage: allows identification of non-sentinel metastases (important prognostically); may improve disease-free survival by removing micrometastatic disease (although only 15-20% of patients actually have this)
** The maximum diameter of the largest tumour deposit in sentinel node is the best prognostic factor for micrometastatic disease