Invasive melanoma patients are open to the risk of metastasis to local lymph nodes.
Careful examination of lymph nodes is a critical component of follow-up protocol with these patients. Lymph nodes with melanoma cells present can get larger very rapidly, sometimes within 24 hours. An affected lymph node is generally not painful and is hard on palpation. The likelihood of metastasis to lymph nodes correlates with the depth of the primary melanoma.
The following is an excerpt of the recommendations of the Australian Cancer Network’s Clinical Practice Guidelines from the Management of Melanoma in Australia and New Zealand.
Sentinel lymph node biopsy (SLNB) should be discussed with patients who have a primary tumour 1.0 mm thick. In addition, there are other patients with thinner tumours who are at particular risk of having a positive sentinel node. Therefore SLNB may be discussed with patients with melanomas < 1mm thick based on the characteristics of the primary tumour, such as ulceration, Clarkes level (IV or V), or a high mitotic rate. Where the true thickness cannot be determined, usually because the melanoma was diagnosed by shave biopsy, patients may also be offered SLNB.
The risk of micrometastatic disease is inversely related to the patient’s age and those younger than 35 years with a thin primary may benefit from sentinel node biopsy. Patients with thick primaries (4mm or greater) are at substantial risk of developing disseminated metastatic disease. However, the status of the sentinel node in these patients is still the most important prognostic factor in this group of patients and biopsy may be recommended to assist in determining prognosis and to improve local disease control.
Good practice points
- A therapeutic node dissection includes a full levels (I to III) clearance in the axilla.
- A therapeutic neck dissection may include a superficial parotidectomy as clinically indicated.
- Patients with inguinal node metastases should be considered for clearance of the intra-pelvic iliac and obturator nodes when the staging investigation demonstrates evidence of involvement.
- Elective clearance of the pelvic nodes be considered when there is gross macroscopic disease in the inguinal node field or there are three or more histologically positive nodes below the level of inguinal ligament.
- Patients with lymph node metastases should be offered discussion with a multidisciplinary team with a view to enrolment in clinical trials.
For more information about Clinical Practice Guidelines, visit cancer.org.au website and download Clinical Practice Guidelines for the Management of Melanoma in Australia and New Zealand (November 2008).
For more information about Sentinel Lymph Node Biopsy in Patients With Melanoma, visit emedicine.medscape.com website.