The institutional review board of Peking University First Hospital approved this retrospective study and waived the requirement for patient informed consent. A total of 81 patients diagnosed with RAML were treated in our hospital from February 2018 to April 2020. The inclusion criteria were as follows: (1) aged 18 and older; (2) pathological or radiological confirmed diagnosis of RAML; (3) at least one tumor with the maximum diameter 3 cm or greater by enhanced computed tomography (CT) or magnetic resonance imaging (MRI); (4) no history of tumor embolization in the past 6 months. Patients were excluded if (1) they were in pregnancy or lactation, or planned for pregnancy; (2) they needed other surgeries such as nephrectomy; (3) they had willingness of conservative treatment rather than invasive surgery; (4) they had history of atherosclerosis related coronary heart disease, myocardial infarction, or cerebral infarction; (5) they had treatment history of mTOR inhibitors, such as rapamycin, sirolimus or everolimus; (6) they had serious heart, lung, or kidney disease that were not able for interventional therapies.
We performed routine treatments regarding rehydration therapy for all patients before conventional TACE (cTACE) or CSM-TACE operation. For cTACE group, the chemotherapy drug solution contained 10 ml lipiodol and 15 mg bleomycin solution, and 8Spheres® particles (Jiangsu Hengrui Medicine Co. Ltd., Jiangsu, China) were used as embolization agents. And for CSM-TACE group, we used CalliSpheres® Beads (CB) (Jiangsu Hengrui Medicine Co. Ltd., Jiangsu, China) with diameter of 100 to 300 μm or 300 to 500 μm according to the presence of arteriovenous shunt or the size of arterial fistula. CB was loaded in bleomycin solution with concentration of 20 mg/ml after all liquid supernatant was pushed out, then was mixed with nonionic contrast agent at a ratio of 1:1. The mixture was shaken and placed for 5 minutes before using. In addition, 2.6 F and 2.7 F microcatheters (Merit Maestro, Merit Medical System Inc., South Jordan, UT, USA) were used in both cTACE and CSM-TACE operations.
All operation process referred to Chinese Clinical Practice Guidelines for Transarterial Chemoembolization of Hepatocellular Carcinoma (2018) (21). All patients received renal angiography before and 10 minutes after the operation.
cTACE group: First, clarified the location, number and form of bilateral renal artery incision, as well as the presence of participation in blood supply for accessory renal artery, lumbar artery, renal capsule artery, phrenic artery, or other systemic vessels. Second, applied microcoil to the lesion before precise embolization for patients comorbid with aneurysm. Third, mixed lipiodol emulsion was injected into the tumor-feeding artery through a microcatheter, then 8Spheres® blank particles were used for supplementary embolization. The endpoint of cTACE procedure was the stasis of blood flow of target artery observed.
CSM-TACE group: First, clarified the location, number and form of bilateral renal artery incision, as well as the presence of participation in blood supply for accessory renal artery, lumbar artery, renal capsule artery, phrenic artery, or other systemic vascular. Second, 100 to 300 μm or 300 to 500 μm CalliSpheres® Beads loaded with bleomycin solution was manually injected into the tumor-feeding artery slowly and carefully to avoid reflux of the mixture into non-targeted vessels. The endpoint of CSM-TACE procedure was the stasis of blood flow of target artery observed. Five minutes after the observation of stasis of blood flow, perform angiography again to confirm the embolization effect.
All patients’ data were collected from electronic medical records (EMR) which included (1) demographic features: age and gender; (2) clinical features: comorbidity, postoperative complications and length of stay (LOS), tumor status, tumor location (left kidney, right kidney or bilobar), tumor distribution, preoperative and postoperative tumor size in three dimensions; (3) blood routine indexes: white blood cell (WBC); (4) kidney function indexes: creatinine (Cre); (5) embolization materials and location.
Evaluation of efficacy and safety
Evaluation of clinical efficacy was performed before and after DEB-TACE or cTACE treatment by enhanced CT or MRI examination. Preoperative and 3-month postoperative tumor size from left-right (LR), anterior-posterior (AP), and superior-inferior (SI) directions were recorded. Tumor volume was measured using an ellipsoid formula (π/6*LR*AP*SI) from the imaging results and volume change rate was calculated (22).
Safety evaluation included WBC while creatinine and its change as the assessments of kidney function according to the laboratory indices at the third day after the operation. Also, adverse events in the perioperative period were documented.
Continuous variables were expressed as mean or median±standard deviation for normally distributed and non-normally distributed ones, separately. Numerical differences between two groups were assessed by chi-square test for categorical variables, and t test or Wilcoxon rank-sum test for continuous variables. The threshold for significance was P=0.05. All statistical analyses were conducted using SPSS, Version 19.0 (SPSS Inc., Chicago, IL, USA).