Using sunscreen and avoiding UV light may prevent melanoma. Treatment is typically removal by surgery. In those with slightly larger cancers, nearby lymph nodes may be tested for spread (metastasis). Most people are cured if spread has not occurred. For those in whom melanoma has spread, immunotherapy, biologic therapy, radiation therapy or chemotherapy may improve survival. With treatment, the five-year survival rates in the United States are 99% among those with localized disease, 65% when the disease has spread to lymph nodes and 25% among those with distant spread. The likelihood that melanoma will reoccur or spread depends on its thickness, how fast the cells are dividing and whether or not the overlying skin has broken down.