Sentinel node tumor status a key factor in melanoma prognosis
New research by Dr. Kashani-Sabet and colleagues reinforces sentinel node tumor status as a key factor in melanoma prognosis
February 12, 2014 (San Francisco, CA)
Helping resolve a century-old clinical question about the optimal management of patients with primary cutaneous melanoma, an international collaboration of researchers found that management based on sentinel node biopsy can prolong disease-free survival in patients whose disease has already spread to the regional nodes.
The findings are the first long-term evidence from randomized trials validating the importance of sentinel node biopsy in the staging and treatment of most types of melanoma, as published online today in the New England Journal of Medicine.
“This publication is the culmination of nearly 20 years of research carried out worldwide,” explained Mark Faries, MD, FACS, Director of the Melanoma Research Program at the John Wayne Cancer Institute (JWCI) at Saint John’s Health Center in Santa Monica, CA, and author of the study. “We now have the best evidence yet that the sentinel node procedure not only gives patients the most accurate information about their future, it also increases their chances for survival.”
“In addition to its considerable impact on recurrence and disease-free survival, sentinel node biopsy provides previously unattainable staging accuracy that facilitates identification of high-risk candidates for adjuvant therapy with standard and novel agents,” said Mohammed Kashani-Sabet, MD, Director of the California Pacific Medical Center (CPMC) Center for Melanoma Research and Treatment in San Francisco, CA, Senior Scientist at CPMC’s Research Institute, and a co-author of the study.
Sentinel node biopsy is a minimally invasive, low-risk regional node staging procedure performed at the time of wide excision. The sentinel node is the initial site of regional metastases, and studies have shown that if it is metastasis-free, the remaining regional nodes will most likely be tumor free. However, if the sentinel node contains metastases, other nodes in the surrounding region may also contain metastases. Sentinel lymph node status has emerged as an important stratification factor for clinical trials of novel adjuvant therapies.
The new research represents long-term results of the Multicenter Selective Lymphadenectomy Trial (MSLT-I), a study of 2001 patients begun in 1994 to examine the utility and effectiveness of sentinel node biopsy and lymphadenectomy in staging and managing patients with intermediate-thickness (1.2-3.5 mm) primary melanomas. The present study includes 10-year follow-up data, with results for patients with thick (>3.5 mm) and thin (<1.2 mm) primary melanomas.
Eligible patients were randomly assigned to wide local excision and sentinel node biopsy (biopsy group), or wide local excision and postoperative nodal observation (observation group). Observation-group patients received delayed lymphadenectomy if metastases were detected in the regional lymph node basin.
The primary endpoint was overall survival. Other endpoints were disease-free survival, melanoma-specific survival, survival by sentinel node status, incidence of nodal metastasis, and survival by nodal status.
In the biopsy group, sentinel node status was the most important prognostic factor for 10-year melanoma-specific survival of patients with intermediate or thick melanoma. Ten-year disease-free survival with biopsy versus observation was 71.3% versus 64.7% in patients with intermediate-thickness melanoma (p=0.0105), and 50.7% versus 40.5% in patients with thick melanoma (p=0.0273). For patients with nodal metastases from intermediate-thickness melanoma, biopsy instead of observation yielded better 10-year distant disease-free survival and melanoma-specific survival.
“On the basis of the substantial outcome data in this study, we recommend sentinel node biopsy for nodal staging in patients with intermediate and thick primary melanomas, and selected patients with thin primary melanoma,” said Dr. Kashani-Sabet.
Ongoing research by CPMC investigators is focused on optimal selection of patients with an increased risk of lymph node metastasis, and the development and validation of molecular markers of melanoma lymph node metastasis.
This year alone, more than 76,000 people will be diagnosed with melanoma in the U.S. The study was funded by the National Institutes of Health (grant CA 29605).