Role of sentinel lymph node biopsy as a staging procedure in patients with melanoma: A critical appraisal

Metastatic melanoma vs lymphoma. Using a sentinel lymph node biopsy a diagnostic tool

Sentinel lymph node biopsy (SLNB) is a prognostic tool used in cases of melanoma with a stage IB or greater and the absence of clinical lymphadenopathy. A positive SLNB historically indicated a need for regional lymph node clearance. However, cases of clinical lymphadenopathy in the presence of primary melanoma negates the use of SLNB and rather the British Association of Dermatologists advocate a primary block dissection of regional lymphatic tissue [NICE UK. Melanoma: assessment and management. NICE Guideline NG 14. 2015]. The following describes the case of a patient with an original stage II melanoma and a concurrent diagnosis of B cell lymphoma associated with widespread lymphadenopathy. Our multi-disciplinary team believe the use of SLNB is a more informative investigation compared with ultrasonograpphy and fine needle aspiration for such cases. In cases of clinical uncertainty due to a dual diagnosis of lymphoma, cytology would not provide nodal morphology or histological architecture, required for lymphoma grade and subtype.

Tumour mutation status and melanoma recurrence following a negative sentinel lymph node biopsy

BACKGROUND

A proportion of patients develop recurrence following a tumour-negative sentinel lymph node biopsy (SLNB). This study aimed to explore whether melanoma patients with BRAF or NRAS mutant tumours have an increased risk of developing disease recurrence following a negative SLNB compared to patients with wild-type tumours.

METHODS

Prospective cohort study of melanoma patients at three tertiary referral centres in Melbourne, who underwent SLNB. Clinical, pathological and molecular characteristics and recurrence data were prospectively recorded. Multivariate Cox proportional hazards regression models estimated the adjusted hazard ratio (aHR) and corresponding 95% confidence interval (CI) for the association between mutation status and development of recurrence following a negative-SLNB.

RESULTS

Overall, 344/477 (72.1%) patients had a negative SLNB. Of these, 54 (15.7%) developed subsequent recurrence. The risk of disease recurrence following a negative SLNB was increased for patients with either a BRAF or NRAS mutant tumour compared to wild-type tumours (aHR 1.92, 95% CI: 1.02-3.60, p = 0.04).

CONCLUSION

Melanoma patients with BRAF or NRAS mutant tumours had an increased risk compared to patients with BRAF/NRAS wild-type tumours of developing disease recurrence following a tumour-negative SLNB. The findings also confirm the importance of continued surveillance to monitor for disease recurrence among SLNB-negative patients.