Sentinel lymph node biopsy can predict (and aid) survival rates

The study examined the benefits of sentinel lymph node biopsy for intermediate-thickness melanoma patients.

For patients with intermediate-thickness melanoma (between 1mm and 4mm thick), the presence of cancer in the lymph nodes is an indicator of a more negative outcome. Lymph node dissection (removal) is often advised for intermediate-thickness melanoma, regardless of whether the lymph nodes are known to be involved. However, it is not clear whether dissection aids survival rates.

Sentinel lymph node biopsy (a biopsy of the lymph node cancer is most likely to spread to first) is a less invasive method of determining nodal involvement, which could help to define who would benefit from a lymph node dissection. Studies have found that sentinel lymph node biopsy can improve disease-free survival compared to simply observing the nodes (nodal observation), but not necessarily melanoma-specific survival times (time until death due to melanoma).

The current study examined whether sentinel lymph node biopsy improved melanoma-specific survival in patients with intermediate-thickness melanoma. This study analyzed the records of 15,274 patients who underwent either sentinel lymph node biopsy (10,605 patients) or nodal observation (4,669 patients). Patients were followed for an average of 47 months.

Overall, 86.6% of patients had a melanoma-specific survival or 5 years or more. The 5-year survival rate for those who had sentinel lymph node biopsy (87.8%) was significantly greater than those who underwent nodal observation (83.9%). Of the patients who received sentinel node biopsy, a higher survival rate was seen in patients with a negative biopsy (90.9% had a 5-year survival) compared to those with a positive biopsy (71.7% had a 5-year survival).

Multiple factors were identified that increased the risk of a shorter survival. Nodal observation increased the risk of short survival times by 18%, male gender increased the risk by 33%, ulceration (breakdown of the skin over the melanoma) by 77%, and location (trunk, head, and neck) of the melanoma by 24-34%.

This study concluded that sentinel node biopsy was associated with an increase in melanoma-specific survival, but mainly in patients for whom the cancer had not spread to the lymph nodes.