Sentinel lymph node biopsy may help guide treatment decisions in stage II melanoma
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Sentinel lymph node biopsy was effective as a prognostic and staging tool in stage IIB/C melanoma, according to a study.
“Pembrolizumab (Keytruda, Merck), an antibody against programmed cell death receptor 1 (PD-1), was recently approved as an adjuvant therapy for patients with high risk clinically localized advanced melanoma at clinical stage IIB/C,” Cimarron E. Sharon, MD, of the department of surgery at the University of Pennsylvania, Perelman School of Medicine, Philadelphia, told Healio. “This is significant because this is the first modern adjuvant therapy to be approved for patients without documented at least stage III disease, which is the most commonly identified by sentinel lymph node microstaging.”
Sharon added that, because of this, the utility of sentinel lymph node biopsy overall has been called into question for patients with clinical stage IIB/C melanoma who are now eligible to receive adjuvant anti-PD-1 therapy without undergoing sentinel lymph node biopsy.
“We wanted to evaluate the utility of sentinel lymph node biopsy for patients with stage IIB/C disease, hypothesizing that sentinel lymph node status could still provide valuable prognostic information to patients and providers which can help with decision-making,” she said.
The analysis included 4,391 patients with clinical stage IIB/C cutaneous melanoma who underwent wide local excision and biopsy between 2004 and 2011. Findings were culled from the Surveillance, Epidemiology, and End Results database.
“This study employed a decision curve/net benefit analysis, which is a relatively new statistical technique to quantify the utility of diagnostic and prognostic tests or procedures,” Sharon said. “Net benefit is unique because it evaluates both the benefits and harms of a given procedure.”
In the current study, the net benefit analysis weighs the benefits of treating a patient with adjuvant therapy who would otherwise succumb to their disease with the harm of unnecessary treatment, according to Sharon.
“This novel statistical method directly assists providers in decision-making through a risk-benefit calculus,” she said. “Providers can decide at what risk threshold of 5-year melanoma-specific death they deem appropriate for administration of adjuvant therapy, and then use the decision curve analysis to determine if at their chosen risk threshold, the performance of sentinel lymph node biopsy would provide a net benefit.”
Treatment thresholds for 20% to 40% risk of 5-year melanoma-specific death served as the primary endpoint.
Results showed that the 5-year melanoma-specific death rate for the full cohort was 46%.
“The model estimating 5-year melanoma-specific death risk that included sentinel lymph node status provided greater net benefit at treatment thresholds from 30% to 78% compared to the model without SLN status,” the researchers wrote.
The trend toward additional benefit of the biopsy-containing model remained through subgroup analysis.
“We assessed the net benefit of sentinel lymph node biopsy across T stages — T3b, T4a and T4b — and different age groups, for patients younger than 65 years or 65 or older,” Sharon said. “We were surprised by the magnitude of the net benefit of sentinel lymph node biopsy specifically for the younger cohort. For this cohort of patients, with the prediction model incorporating sentinel lymph node data at the chosen treatment threshold of 35%, a net of approximately 11 patients would correctly avoid adjuvant therapy for every 100.
“Sentinel lymph node biopsy remains an important component of staging and prognostication in patients with clinical stage IIB/C melanoma and can help guide decisions for adjuvant therapy,” Sharon concluded. “Moreover, it can provide regional control of disease with relatively low morbidity.”