Sentinel lymph node diagnostic evaluation
Sentinel lymph node diagnostic evaluation is currently offered for tumours over 1 mm in thickness and performed at the same time as wide excision (9). It is reported that 20 % of patients with tumour thickness 1–4 mm have sentinel lymph node metastasis. Of these patients, 15–20 % have spread to further lymph nodes in the same regional lymph node basin (15).
The rate of finding positive sentinel lymph nodes is low with tumour thickness below 0.8 mm (pT1a), and the procedure should not be offered to this patient group. Young patients with tumour thickness of 0.8–1.0 mm with ulceration or mitoses can be assessed for sentinel lymph node diagnostic evaluation by a multidisciplinary team (2).
Wide excision and sentinel lymph node diagnostic evaluation are generally performed as day surgery with preoperative lymphoscintigraphy and single-photon emission computed tomography (SPECT)-CT the day before. A gamma probe and, if appropriate, patent blue are used peroperatively to locate sentinel lymph nodes, which can be challenging to find, particularly in the neck. Therefore, patients with melanoma in the head/neck region can be referred to a university hospital for this diagnostic evaluation. If the sentinel lymph nodes are not accessible for surgery, the patient can be referred for ultrasound examination, if necessary with fine needle aspiration cytology if suspect lymph nodes are found. The specimen(s) are sent to a pathologist for diagnostic evaluation.
If sentinel lymph node metastasis is found, adjunctive treatment may be appropriate. These patients are discussed by a multidisciplinary team. Factors such as the aggressiveness of the primary tumour (Breslow thickness, ulceration, mitotic rate), as well as the size of metastatic foci in the lymph node and comorbidities, determine further follow-up and treatment.
Completion lymph node dissection was previously the standard treatment to prevent regional recurrence and further spread of the disease. This is no longer routinely recommended today (16, 17).