Sentinel-Node Biopsy Leads to Improved Intermediate-Thickness Melanoma Disease-Free Survival

Sentinel-node biopsy of intermediate-thickness melanomas provides important staging and disease management information, including identifying the need for immediate lymphadenectomy

medwireNews: Sentinel-node biopsy followed by immediate lymphadenectomy for those with nodal metastases should be used in patients with intermediate-thickness or thick primary melanomas, indicate long-term results from the Multicenter Selective Lymphadenectomy Trial.

“The procedure provides accurate and important staging information, enhances regional disease control, and, among patients with nodal metastases, appears to improve melanoma-specific survival substantially,” say the researchers, led by Mark Faries, from Saint John’s Health Center in Santa Monica, California, USA.

The study involved 1270 patients with intermediate-thickness (1.20 to 3.50 mm) and 290 with thick (>3.50 mm) primary melanomas, of whom 770 and 173, respectively, were randomly assigned to undergo wide excision of the primary melanoma and sentinel-node biopsy, with immediate lymphadenectomy if nodal metastases were detected on biopsy. The remaining patients underwent wide excision and nodal observation with lymphadenectomy carried out on nodal relapse.

There was no significant difference between the two treatment groups with regard to 10-year melanoma-specific survival, for either intermediate or thick melanomas. But biopsy was associated with a significant improvement in 10-year disease-free survival, with rates of 71.3% versus 64.7% for patients with melanomas of intermediate thickness and 50.7% versus 40.5% for those with thick melanomas, and respective hazard ratios (HRs) of 0.76 and 0.70.

The researchers note in The New England Journal of Medicine that sentinel-node biopsy correctly determined the pathological status of the nodal basin in 96% of cases and was the strongest predictor of disease recurrence or death from melanoma.

Among patients with intermediate-thickness melanomas, the 10-year melanoma-specific survival rate was 62.1% among those with sentinel-nodal metastases, compared with 85.1% for those with tumour-free sentinel nodes, at a significant HR for death of 3.09.

For those with thick melanomas, the rates were 48.0% versus 64.6%, respectively, at a significant HR of 1.75.

The researchers report that early lymphadenectomy following positive sentinel-node biopsy significantly lessened the risk of distant metastases, by 38%, and the risk of death from melanoma, by 44%, compared with nodal observation.

There was no significant treatment effect for patients with thick melanomas and nodal metastases, however.

“Although some patients with nodal metastases from thick melanomas may benefit from lymphadenectomy, our findings suggest that the timing of that intervention is not as critical as it is for patients with intermediate-thickness melanomas,” the team comments.

In a related editorial, Charles Balch, from the University of Texas Southwestern Medical Center in Dallas, USA, and Jeffrey Gershenwald, from the University of Texas M.D. Anderson Cancer Center in Houston, USA, call the latest trial “practice-changing”. They say it “shows the important role of early identification and surgical removal of regional metastases, both in obtaining staging information and improving survival in defined cohorts of patients with melanoma.”

References

Morton DL, Thompson JF, Cochran AJ, et al. Final trial report of sentinel-node biopsy versus nodal observation in melanoma. N Eng J Med 2014; 370: 599–609.
Balch CM, Gershenwald JE. Clinical value of the sentinel-node biopsy in primary cutaneous melanoma. N Engl J Med 2014; 370: 663–664.

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