Out of the different types of skin cancer, melanoma ranks as the most deadly. The prognosis for metastatic malignant melanoma depends on the spread and stage of the cancer.
Metastatic Malignant Melanoma
Of the approximately 1 million diagnosed with skin cancer in the United States each year, only 4% of those will have malignant melanoma. Melanoma becomes metastatic when it has spread to the lymph nodes or other parts of the body, such as internal organs. Where it spreads affects the treatment options, as well as the prognosis. Metastatic melanoma affects approximately 15% of those diagnosed with this form of skin cancer and has a diagnosis of stage III or stage IV (Cleveland Clinic). Of those with melanoma that has spread, only 2% have stage IV, or spread to distant parts of the body.
The survival rate of a large group helps determine the prognosis for metastatic malignant melanoma. In 2008, the survival rate of 60,000 individuals with melanoma helped determine the staging prognosis numbers which are currently used and published by the American Cancer Society. These numbers represent survival rates observed in a large population of individuals, but many factors can affect each individual’s response to treatment. For example, patients over the age of 70 generally have a reduced survival rate. The numbers also include melanoma patients who died from other medical causes and don’t take into account new advancements in treatment. The percentages give the number of people that survived at least that long after diagnosis and provide a guideline for giving a prognosis.
When melanoma has reached stage III, it means it has spread to lymph nodes. A stage IIIA diagnosis means the cancer has infected lymph nodes near the original melanoma site, but has not spread throughout the body. The survival rate five years after diagnosis is approximately 78%. At 10 years, it drops to 59%. Stage IIIB melanoma still hasn’t spread beyond regional lymph nodes, but the melanoma may be ulcerated. The prognosis for five years is 59% and 43% for 10 years. Stage IIIC malignant melanoma may spread into the lymphatic system and skin near the original site. The 5-year rate is 40%, while the 10-year rate drops to 24%.
In stage IV melanoma, the cancer has metastasized not only to lymph nodes, but also to distant organs. The prognosis for metastatic malignant melanoma that has reached stage IV is low. The rate five years from diagnosis is 15% to 20%. The 10-year survival rate is 10% to 15%. If the melanoma reaches the lungs, the rate drops as low as 3% for 10 years, according to the 2002 Revised Melanoma Staging. The overall prognosis for stage IV depends on where the melanoma has spread and how it responds to treatment.