In patients who have melanoma with sentinel node metastasis, immediate-completion lymph node dissection doesn’t improve melanoma-specific survival, compared with nodal observation using ultrasound, according to a report published online June 8 in the New England Journal of Medicine.

Immediate-completion lymph node dissection – removal of the remaining regional lymph nodes after sentinel node excision – is usually recommended for patients found to have sentinel node metastasis, even though the evidence supporting this practice is inconclusive. A large prospective phase III trial was performed to compare outcomes with this approach against outcomes in patients who instead underwent observation using frequent nodal ultrasound and had lymph node dissection only if nodal recurrence developed, said Mark B. Faries, MD , of the John Wayne Cancer Institute at Saint John’s Health Center, Santa Monica, Calif., and his associates.

The second Multicenter Selective Lymphadenectomy Trial (MSLT-II) involved 1,939 adults at 63 medical centers who had clinically localized cutaneous melanoma of intermediate thickness, at least one tumor-positive sentinel node as determined by standard pathological assessment or a quantitative reverse transcriptase–polymerase chain reaction assay, and a life expectancy of 10 years or more. These participants were randomly assigned to immediate-completion node dissection (971 patients) or nodal observation (931 patients).

At 3 years of follow-up, the primary end point – the rate of melanoma-specific survival – was the same in the immediate-dissection group as in the observation group (86%). Further analyses showed that no subgroup of patients, including those defined by tumor burden, showed a significant melanoma-specific benefit from immediate completion lymph node dissection. However, the immediate-dissection group had a significant disadvantage regarding adverse events; 24.1% developed lymphedema, compared with only 6.3% of the observation group.

Secondary end points slightly favored immediate dissection. At 3 years, the rate of disease-free survival was slightly higher in that group (68%) than in the observation group (63%), and the rate of disease control in the regional nodes was higher (92% vs. 77%). However, “differences with respect to the secondary end points must be interpreted with caution,” Dr. Faries and his associates said (N Engl J Med. 2017 Jun 8. doi: 10.1056/NEJMoa1613210 ).

“Overall, some value may be derived from immediate-completion lymph node dissection with regard to staging and an increased rate of regional disease control. However, this value comes at the cost of increased complications,” the investigators said.

This study was supported by the National Cancer Institute, the Borstein Family Foundation, Amy’s Foundation, the Dr. Miriam and Sheldon G. Adelson Medical Research Foundation, and the John Wayne Cancer Institute Auxiliary. Dr. Faries reported serving on advisory boards for Myriad Genetic Laboratories, Amgen, and Immune Design; his associates reported ties to numerous industry sources.