Prognosis
Factors that affect prognosis include:

tumor thickness in millimeters (Breslows depth),
depth related to skin structures (Clark level),
type of melanoma,
presence of ulceration,
presence of lymphatic/perineural invasion,
presence of tumor-infiltrating lymphocytes (if present, prognosis is better),
location of lesion,
presence of satellite lesions, and
presence of regional or distant metastasis.Certain types of melanoma have worse prognoses but this is explained by their thickness. Less invasive melanomas even with lymph node metastases carry a better prognosis than deep melanomas without regional metastasis at time of staging. Local recurrences tend to behave similarly to a primary unless they are at the site of a wide local excision (as opposed to a staged excision or punch/shave excision) since these recurrences tend to indicate lymphatic invasion. When melanomas have spread to the lymph nodes, one of the most important factors is the number of nodes with malignancy. Extent of malignancy within a node is also important; micrometastases in which malignancy is only microscopic have a more favorable prognosis than macrometastases. In some cases micrometastases may only be detected by special staining, and if malignancy is only detectable by a rarely employed test known as the polymerase chain reaction (PCR), the prognosis is better. Macrometastases in which malignancy is clinically apparent (in some cases cancer completely replaces a node) have a far worse prognosis, and if nodes are matted or if there is extracapsular extension, the prognosis is worse still.
Biochemotherapy (chemotherapy with cytokines IL-2 and IFN-α) combined with BRAF inhibitors improved survival for people with BRAF positive melanoma. Biochemotherapy alone did not improve overall survival and had higher toxicity than chemotherapy. Combining multiple chemotherapy agents (polychemotherapy) did not improve survival over monochemotherapy. Targeted therapies result in relatively short progression-free survival (PFS) times. The therapy combination of dabrafenib and trametinib has a 3-year PFS of 23%, and 5-year PFS of 13%. Immunotherapy
Immunotherapy is aimed at stimulating the persons immune system against the tumor, by enhancing the bodys own ability to recognize and kill cancer cells. The current approach to treating melanoma with immunotherapy includes three broad categories of treatments including cytokines, immune check point inhibitors, and adoptive cell transfer. These treatment options are most often used in people with metastatic melanoma and significantly improves overall survival. However, these treatments are often costly. For example, one immune check point inhibitor treatment, pembrolizumab, costs $10,000 to US$12,000 for a single dose administered every 3 weeks.Cytokine therapies used for melanoma include IFN-a and IL-2. IL-2 (Proleukin) was the first new therapy approved (1990 EU, 1992 US) for the treatment of metastatic melanoma in 20 years. IL-2 may offer the possibility of a complete and long-lasting remission in this disease in a small percentage of people with melanoma. Intralesional IL-2 for in-transit metastases has a high complete response rate ranging from 40 to 100%.