NEW YORK — Sentinel lymph node biopsy after wide excision improved DFS compared with wide excision alone among patients with intermediate and thick melanomas, according to final results of the MSLT-1 trial presented at the HemOnc Today Melanoma and Cutaneous Malignancies meeting in New York.
“We found that performing sentinel lymph node biopsy is very accurate and improves staging in order to determine whether additional treatments are needed, such as additional surgery or adjuvant systemic therapy,” Robert H.I. Andtbacka, MD, CM, FACS, FRCSC, associate professor of surgery at Huntsman Cancer Institute at the University of Utah, said during a presentation. “It also forms a basis for us to perform all the subsequent studies that we do in melanoma to make sure patients we have for our clinical trials are well balanced.”
Robert H.I. Andtbacka
Andtbacka and colleagues enrolled 2,001 patients. The cohort included 340 patients with thin melanomas (˂1.20 mm), 1,347 with intermediate-thickness (1.20 to 3.50 mm) melanomas and 314 with thick melanomas (˃3.50 mm).
The investigators randomly assigned 40% of patients to wide excision alone, and 60% underwent wide excision followed by sentinel-node biopsy.
Researchers conducted complete lymph node dissection among patients in the wide excision arm who experienced recurrence, and among patients in the sentinel-node dissection arm who had positive sentinel nodes. Patients with negative nodes, or those without recurrence in the control arm, underwent observation.
Melanoma-specific survival served as the primary endpoint, and DFS served as the secondary endpoint.
At the time of the final, 10-year analysis, 996 patients were evaluable.
Overall, researchers observed no significant difference in disease-specific survival between the two arms (HR=0.84; 95% CI, 0.64-1.09).
However, sentinel-node biopsy was associated with improved DFS among patients with intermediate-thickness (HR=0.76; 95% CI, 0.62-0.94) and thick (HR=0.70; 95% CI, 0.50-0.96) melanomas.
Sentinel node metastases were associated with worse melanoma-specific survival among patients with intermediate-thickness (HR=3.09; 95% CI, 2.12-4.49) and thick (HR=1.75; 95% CI, 1.07-2.37) melanomas.
Results of multivariate analysis showed positive vs. negative sentinel-node status was the most significant predictor of disease recurrence (HR=2.64; 95% CI, 1.92-3.64) and death from melanoma (HR=2.40; 95% CI, 1.61-3.56).
Patients who underwent immediate complete lymph node dissection had a mean of 1.4 ± 0.1 positive lymph nodes, whereas patients who were observed had a mean of 3.3 ± 0.5 positive lymph nodes. More patients in the observation group had stage ˃4 nodes (27% vs. 5%) and stage 2 to 3 nodes (32% vs. 28%), whereas more patients who underwent immediate dissection had stage 1 nodes (67% vs. 41%).
“This is important from a surgical perspective,” Andtbacka said. “Taking out lymph nodes that are big and bulky has a potential of having more morbidity for the patients, one of them being lymphedema.”
Researchers have completed enrollment for the MSLT II trial, which aims to compare complete dissection vs. observation among patients with microscopic positive sentinel nodes, Andtbacka said.
For more information:
Andtbacka RH. Final results of the MSLT-1 Trial. Presented at: HemOnc Today Melanoma and Cutaneous Malignancies; April 10-12, 2014; New York.
Disclosure: The researchers report no relevant financial disclosures.