Sentinel-Node Biopsy Reduced Recurrence, Increased Melanoma-Specific Survival

Image of a thick melanoma (> 4 mm)

The use of sentinel-node biopsy for patients with intermediate-thickness melanomas provided accurate staging information, increased disease-free survival, and, in patients positive for nodal metastases, increased disease-specific survival, according to the final, long-term data from the Multicenter Selective Lymphadenectomy (MSLT)-I study.

“These results confirm that for patients with intermediate-thickness melanomas who have clinically occult nodal metastases, early intervention decreases the risk of nodal recurrence, distant metastases, and death from melanoma,” wrote researchers led by Donald L. Morton, MD, of the department of surgical oncology at John Wayne Cancer Institute, Santa Monica, Calif.

Started in 1994, the MSLT-I was designed to determine if immediate-completion lymphadenectomy resulted in better patient outcomes than when lymphadenectomy was performed only in the presence of evidence of nodal recurrence during an observation period. These 10-year follow-up results, published in the New England Journal of Medicine, report on both patients with intermediate-thickness melanomas (n = 1,270) and those with thick primary melanomas (n = 290).

The study included 2,001 patients with primary cutaneous melanoma who were randomly assigned to wide excision and nodal observation with lymphadenectomy for nodal relapse, or the intervention of wide excision and sentinel-node biopsy with lymphadenectomy upon detection of nodal metastases.

No significant treatment-related difference was found for the 10-year melanoma-specific survival rate among all patients with intermediate-thickness melanomas. However, in an accompanying editorial published with the research, Charles M. Balch, MD, of the University of Texas Southwestern Medical Center, and Jeffrey E. Gershenwald, MD, of the University of Texas MD Anderson Cancer Center, pointed out that since only 20% of patients with intermediate-thickness melanomas had nodal metastases, only a small proportion of the total population could derive benefit from sentinel-node biopsy.

“This overall finding does not detract from the clinical importance of regional lymph-node staging, however, or the improved survival observed among the patients with tumor-positive sentinel nodes and intermediate-thickness melanomas,” Bach and Gershenwald wrote.

Patients with intermediate-thickness melanomas undergoing biopsy had significantly improved 10-year disease-free survival compared with the observation group (71.3% vs 64.7%; HR = 0.76; P = .01). The same was observed in patients with thick melanomas defined at more than 3.5 mm (50.7% vs 40.5%; HR = 0.70; P = .03).

Looking at only those patients with nodal metastases, undergoing sentinel biopsy resulted in a 10-year melanoma-specific survival of 62.1% compared with 41.5% for nodal positive patients in the observation group, a 44% improvement (P = .006). In addition, the early intervention improved the 10-year rate of disease-free survival by 38% (P = .04).

No significant treatment-related difference was seen for 10-year melanoma-specific survival in patients with thick melanomas with nodal metastases (48% for biopsy vs 45.8% for observation; P = .078).

“The MSLT-I results strongly support the continued use of sentinel-node biopsy in surgical practice and reinforce guideline recommendations made by the American Society of Clinical Oncology and the Society of Surgical Oncology,” Bach and Gershenwald wrote. “This practice-changing trial shows the important role of early identification and surgical removal of regional metastases, both in obtaining staging information and in improving survival in defined cohorts of patients with melanoma.”