Renal carcinoma with solitary lung secondary is best treated by
Radiotherapy
Surgery
Chemotherapy
Immunotherapy
Surgery is the best option because 1) cytoreductive surgery will help in increase the action of immunotherapy 2) metstatectomy ( surgery to remove metstatectomy ) with curative intent has good prognosis in pulmonary Mets Ref : Campbell and Walsh urology 11th edition . chapter 63. pg no 1502
Urology