In a nutshell
The authors measured the spread of melanoma to the lymph nodes and analyzed the effect of cancer spread on patient survival.
Some background
In skin melanoma, sentinel lymph node (SLN) is the first lymph node (tiny, bean-shaped organ that helps fight infection) to which the cancer cells spread (metastasis). The presence of SLN is determined by a procedure called sentinel lymph node biopsy (SLNB). It involves taking a tissue sample to determine whether the cancer has spread to the nearby lymph nodes. However, the value of SLN as a predictor of cancer spread is not widely accepted. This is because the process of measuring the amount of SLNs is extremely time-consuming. Additionally, the techniques that are routinely used are not capable of measuring the tumor cells accurately.
There is a need to develop a better analytical technique to establish the utility of quantifiable SLNs as a predictor of cancer spread.
Methods & findings
The authors aimed to quantify the amount of melanoma spread in SLNs and their effect on patient survival.
1,834 SLNs from 1,027 patients were analyzed in this study. The median (midpoint) follow-up time was 49 months. Patients had node-negative melanoma (no cancer spread in the lymph nodes) based on previous ultrasound results and underwent SLNB. 52 non-melanoma patients were included in this study as controls.
The number of widely spread cancer cells present in the lymph nodes was measured using a potential biomarker (indicator used to predict the presence of a disease) called disseminate cancer cell density (DCCD). Patients with high DCCD had an increased risk of melanoma death compared to patients with low DCCD. Lymph nodes were also tested for presence of gp100 (a protein associated with skin cancer).
None of the patients in the control group had gp100 protein. 51% of melanoma patients had gp100 protein in their SNLs. 13.4% of patients died from melanoma. 5-year melanoma-specific survival (patients who did not die from melanoma following treatment) was 86%. Patients who experienced a 10 times increase in DCCD had a 81% higher risk of experiencing melanoma death. Patients with a relatively low DCCD (less than 3) still had a 1.63 times increased risk of dying from melanoma compared to patients who had a DCCD of 0. The most useful predictive factors for survival and cancer spread in melanoma were tumor thickness (how far the cancer reached deep into the skin), ulceration (tumor breaking through skin’s surface) and DCCD.
The bottom line
The authors concluded that spreading of cancer cells to the sentinel lymph node was a measurable risk factor in melanoma survival.
Published By :
Plos Medicine
Date :
Feb 01, 2014
