Toxicity evaluation
The occurrence of toxicity was retrospectively collected according to history record and laboratory test record. Suspected related adverse events including lethargy, arthralgia, edema, headache, vomiting, nausea, stomachache, dizziness, constipation, diarrhea, distension of the abdomen, peripheral neuropathy (numbness of extremities), chest tightness, skin rash, were recorded. White blood cell counts, absolute neutrophil count, platelet counts, aspartate aminotransferase levels, alanine aminotransferase levels, total bilirubin levels, γ-glutamyl transpeptidase, creatine levels, blood urea nitrogen levels were also recorded. Adverse events and toxicity were graded by modified Common Terminology Criteria for Adverse Events (CTCAE) v5.0. According to the guidance from off-label medicine committee, reduced dose or withdrawal thalidomide was performed if grade III/IV adverse events occurred.