A retrospective review of data from 590 patients has associated the size of sentinel lymph nodes with a heightened risk of death due to melanoma.
While the details of the association remain vague, this is the first demonstration that sentinel lymph node size has significance in terms of survival from cutaneous melanoma, researchers reported here at the 2015 Annual Meeting of the American College of Surgeons (ACS)
While the size of the space occupied by the tumour in the sentinel lymph node has been definitively linked with the likelihood of cutaneous melanoma and melanoma-related death, whether the size of the sentinel lymph node itself has prognostic significance has been unknown.
To examine the relationship, Brandon C. Chapman, MD, University of Colorado Anschutz Medical Campus, Aurora, Colorado, and colleagues prospectively examined data from patients treated by sentinel lymph node biopsy at their institution from February 1995 and January 2013.
Patients were excluded if sentinel lymph biopsy was not done, if there was a history of procedures or resections in the involved nodal basin, and patients for whom size or volume measurements were not available.
Sentinel lymph nodes were fixed in formalin prior to volume measurement. The lymph nodes were assumed to be ellipsoidal, which allowed the mathematical computation of their volume.
Multivariable analysis revealed independent associations with death related to cutaneous melanoma of age (hazard ratio [HR] = 1.04; P< .001), sentinel lymph node volume (HR = 1.18; P = .047), ulceration (HR = 2.04; P = .004), and lymph node metastasis (HR = 4.3; P< .001).
"Larger sentinel lymph node volume is associated with a higher risk of melanoma-specific death on multivariate analysis," the authors wrote in their presentation. "The size of the sentinel lymph node may reflect a general immunologic response that is not fully understood in melanoma patients."
The task now becomes to investigate the nature of the association between larger sentinel lymph nodes and death caused by melanoma.
"Lymph nodes may act as gatekeepers of the immune system in cancer development and increased lymph node size may be an indication of greater immunologic activity," the authors explained.