Study to Evaluate Lenalidomide Plus Dexamethasone in Patients With Newly Diagnosed POEMS Syndrome

"12 cycles of lenalidomide and dexamethasone, each cycle lasts 28 days. For patients with Ccr equal to or higher than 30ml/min, oral lenalidomide 10mg once daily for days 1-21 out of a 28 cycle.~For patients with Ccr lower than 30ml/min, oral lenalidomide 10mg once every other day for days 1-21 out of a 28 cycle.~All the patients take Dexamethasone orally 40mg once weekly for day 1,8,15,22 out of a 28 cycle."