Stage IV Melanoma
In Stage IV, the melanoma has traveled beyond the regional lymph nodes to more distant areas of the body. The most common sites of metastasis are to vital organs (lungs, abdominal organs, brain, and bone) and soft tissues (skin, subcutaneous tissues, and distant lymph nodes (lymph nodes beyond the primary tumor region).
Stage IV Melanoma Primary Characteristics Include:
Location of distant metastases
Number and size of tumors
Serum LDH level. LDH (serum lactate dehydrogenase), is an enzyme found in the blood and many body tissues. Elevated LDH levels usually indicate that the tumor has spread to internal organs.
There Are 3 Subclasses of Stage IV Melanoma:
The subclasses are based on where the metastases are located and the level of serum LDH. It does not include any T or N classification.
M1a: the tumor has metastasized to distant skin, the subcutaneous layer or to distant lymph nodes. Serum LDH is normal.
M1b: the tumor has metastasized to the lungs. Serum LDH is normal.
The tumor has metastasized to organs other than the lungs, and serum LDH is normal, OR
There are any distant metastases with elevated LDH
Risk: Unfortunately, long-term survival is poor, with 1-year survival rates ranging from 41% to 59%. (1)
The survival rate of patients with Stage IV melanoma has significantly improved since 1997 compared with patients diagnosed before that year. (2)
Having a normal appetite, absence of nausea, vomiting, or fever, the ability to conduct daily activities unimpaired, and being female all give you a more favorable patient profile.
Why the Location of Metastases Is Important
Large-scale studies indicate that the respective 1-, 2-, and 5 year survival rates for Stage IV melanoma are: (1)
Distant skin, soft tissue, and/or lymph nodes - 54%, 36%, 19%
Lung - 53%, 31%, 15%,
Visceral - 35%, 18%, 9%
Why Brain Metastases Are Different
While brain metastases are part of Stage IV, the risk factors, diagnosis, and treatment, are different than other types of metastases.
Why LDH Levels Are Important
Compared with the survival of patients with normal LDH levels, patients with abnormal LDH levels have significantly worse overall survival. The respective 1-, 2-, and 5 year survival rates were: (2)
Abnormal LDH - 33%, 18%, 10%
Normal LDH - 61%, 33%, 18%