Antitumor related therapy is one of the common causes of thrombocytopenia. Chemotherapy regimens based on drugs such as gemcitabine, platinum, anthracycline, and paclitaxel are high-risk options for thrombocytopenia. The degree of thrombocytopenia caused by external radiation therapy mainly depends on the irradiation dose, irradiation site, irradiation field size, and irradiation duration. The synchronous radiotherapy and chemotherapy regimen for head and neck tumors, esophageal cancer, rectal cancer, and other cancers often involves platinum drugs, and the irradiation site often involves flat and irregular bones. Therefore, the incidence of thrombocytopenia in patients during the treatment process is higher than that of chemotherapy or radiotherapy alone. In a phase III clinical study on the combination of carboplatin and paclitaxel in the treatment of esophageal cancer, the incidence of thrombocytopenia was as high as 54%. Once thrombocytopenia occurs, it may lead to a decrease in chemotherapy drug dosage, delay, and cessation of radiotherapy and chemotherapy, and may require platelet infusion. In follow-up studies of various cancer patients, it has been found that reducing the dosage of chemotherapy drugs or delaying the chemotherapy cycle will reduce treatment efficacy and lead to poor prognosis, including shortened disease-free survival (DFS) and overall survival (OS) time.

TPO-RA drugs are currently approved for indications in the fields of chronic primary immune thrombocytopenia (ITP), severe aplastic anemia (SAA), and chronic liver disease (CLD). There are also relevant data reports in the CIT field. A phase II clinical study using romiplostim for the treatment of CIT enrolled a total of 60 patients. After treatment with romiplostim, 85% of patients returned to normal platelet count within 3 weeks and resumed chemotherapy. In the subsequent prescribed chemotherapy cycle, only 6.8% of patients experienced a relapse due to another round of chemotherapy. The occurrence of CIT leads to a decrease or delay in chemotherapy dose; In another randomized placebo-controlled phase II study using eltrombopag for the prevention of solid tumor CIT, patients received gemcitabine monotherapy or gemcitabine combined with cisplatin/carboplatin regimen chemotherapy, and treated with eltrombopag or placebo 100mg before and 5 days after chemotherapy. In the 1-6 chemotherapy cycles, the average platelet count on the day before chemotherapy in the eltrombopag group was numerically higher than that in the placebo group, but did not reach statistically significant differences. The incidence of grade 3/4 thrombocytopenia in the eltrombopag group was lower than that in the placebo group. Among patients in the combination chemotherapy group, the average time required for eltrombopag group to recover from the lowest platelet count to normal was 8 days. The placebo group, on the other hand, requires 15 days, and the incidence of delayed/reduced chemotherapy dose or dose loss due to thrombocytopenia is lower in patients in the eltrombopag group, Therefore, in gemcitabine based chemotherapy, treatment with eltrombopag can shorten the time for platelet minimum recovery and reduce the delayed/reduced chemotherapy dose caused by thrombocytopenia. However, there is still a lack of stronger evidence-based medicine for the application of TPO-RA drugs in CIT, and there is no relevant data in the field of concurrent chemoradiotherapy induced thrombocytopenia.