Age and sentinel lymph node metastasis in melanoma: is there a connection?

The authors analyzed the relationship between melanoma deaths and sentinel lymph node (SLN) metastases (spread of cancer) in melanoma patients of all ages. 

SLN is the first lymph node or nodes (tiny, bean-shaped organs that help fight infection) cancer cells spread in to. The presence of SLN is determined by a procedure called sentinel lymph node biopsy (SLNB). A biopsy involves taking a tissue sample from a particular site for analysis. Samples that are positive indicate that the cancer has spread. This is known as SLN positivity. Some studies on melanoma have shown that older melanoma patients have fewer occurrences of SLN positivity. This seems to be an apparent contradiction, since several studies have indicated that older melanoma patients are more likely to die of melanoma.

Understanding the association between SLN positivity and age is critical since the reports on survival rates in melanoma, based on current classification systems, are influenced by the presence and absence of lymph node metastases.

The authors aimed to compare SLN positivity and melanoma deaths in a large group of melanoma patients of all ages.

Data from 158,813 melanoma patients was analyzed in this study with an average follow-up time of 45 months. All patients had undergone SLNB .

Patients younger than 20 years had higher occurrences (16.6%) of cancer spreading to near-by lymph nodes compared to patients older than 20 years (9.2%). Cancer spread to distant organs was more common in patients older than 20 years (4.2%) than in patients who were 20 years or younger (2.5%).

8,420 deaths were reported for patients older than 60 years compared to 4,322 deaths in patients younger than 60 years. The odds of melanoma death in 60 to 79 year-olds were 1.83 times higher than melanoma deaths in 20 to 39 year-olds. However, the odds of patients between the ages of 60 and 79 years experiencing SLN positivity were 38% lower compared to patients between 20 to 39 years.

Younger patients with tumor thickness (how far the tumor reached deep into the skin) more than 1 mm thick had higher occurrences of SLN positivity compared to older patients with tumor thickness of more than 1 mm. 

The authors concluded that melanoma deaths in older patients were higher compared to younger patients although older patients were less likely to develop SLN metastasis.  

There was no information on other treatment options available for melanoma (e.g. chemotherapy or combination therapy). Occurrences of adverse side events, if any, were not reported.