AIM: To work out an individualized lipiodol dose in transcatheter arterial chemoembolization (TACE) for large hepatocellular carcinoma (HCC) according to its blood supply evaluated by CT.

METHODS: One hundred patients with large HCC (more than 8 cm in diameter) were studied by multidetector helical CT. Patterns of blood supply of HCC were divided into sufficient blood supply, poor blood supply, mixed blood supply and arteriovenous (A-V) shunt. The dose of ultra-fluid lipiodol was determined by diameter and blood supply type of HCC. Patients were divided into two groups (50 cases each): lipiodol perfusion group and iodized oil perfusion group according to tumor diameter and the blood supply type of tumor.

RESULTS: The confirmation and effective rates were 82%, 84% in the first group and 36%, 46% in the second group (P < 0.01).

CONCLUSION: A relatively individualized lipiodol dose may be determined according to the blood supply pattern and the tumor diameter by CT imaging.

A critical issue in treating large hepatocellular carcinoma (HCC) is determining the optimum lipiodol and antitumor drug dose before transcatheter arterial chemoembolization (TACE). Over-dose will damage hepatic function and inadequate dose will lead to poor treatment effect. Tumor blood supply is the crucial factor for determining lipiodol dose. Lipiodol dose was worked out according to the HCC blood supply check by CT scan, then the actual perfusion dose and curative effect were compared in order to assess the therapeutic efficacy.

Lipiodol dose is determined by tumor blood supply, patients’ general conditions, tolerance to operation, catheter position, etc., of which tumor blood supply plays a crucial role. CT and DSA can display the tumor blood supply well. With sufficient blood supply, tumors in CT scan show apparent enhancement and in DSA display a large amount of inordinately dilated vessels, even “blood lake”. With poor blood supply, tumors reveal little enhancement as well as a small number of vessels. The display rate and staining extent of the vessels were different when the catheter ends reached coeliac trunk, common hepatic artery or proper hepatic artery. Tumor staining extent was significantly higher in latter two because most of blood stream could flow back to splenic artery when catheter was in coeliac trunk. In addition, display rate and staining extent of small vessels were in direct proportion to contrast media amount and injection rate. Two cases revealing no classical trabecula and roundish contrast features in CT were misdiagnosed as poor blood supply type, but the nourishing arteries were presented in arterial phase and a large amount of small vessels appeared in portal venous phase and in DSA lipiodol filled in the tumor completely.

It is of great significance to work out a set of individualized therapy before TACE. Previously, lipiodol dose was determined by tumor’s size[1]. In another word, lipiodol dose should correspond to tumor size and if lipiodol dose is equal to tumor diameter or 1.5 times the diameter, it will produce good curative effect, and if dose is beyond twice the diameter, it will have fewer effects and even damage the hepatic function, leading to cirrhosis. Matsuo[2] believed that in conventional TACE, lipiodol should be over 5 mL if tumor diameter is less than 5 cm, and the maximum dose will be 10 mL when the tumor develops to more than 5 cm in diameter. With the improvement of the catheter quality and the development of the superselective skills, the catheter can be superselected directly into tumor supply arteries with ease, and lipiodol dose can rise up to 20 mL to fill the tumor less than 10 cm in diameter and 30 mL or more to the tumor more than 10 cm. But in poor blood supply cases, the lipiodol dose should not be over its necessity because lipiodol can flow back and disperse into the normal liver parenchyma. As for mixed blood supply, the dose will rely on the sufficient blood supply area in tumor. Tumor has its shape and volume, supposing to make the lipiodol fill in the tumor as much as possible, it is not enough to inject lipiodol dose into tumor just as its maximum diameter, especially in sufficient blood supply tumor. The tumor will survive if lipiodol dose is not sufficient. Theoretically, tumor cell can be killed only when lipiodol has obstructed all supply vessels and drug flows completely into the tumor. Over dose of drug and lipiodol will make hepatic function get worse in the case of the liver cirrhosis. For these reasons above, to make the drug and lipiodol fill as completely in the tumor as possible, lipiodol dose ought to be based not only on tumor diameter but also on individual blood supply.

CT film can reflect tumor’s position, shape, size, quantity as well as blood supply, thus providing guidance for therapy. Patterns of tumor blood supply can be divided into 3 types at arterial phase in CT scan: sufficient blood supply, poor blood supply and mixed blood supply. The survival rate of sufficient blood supply is obviously higher than that of poor blood supply[3,4]. Vogl[5] held that lipiodol filling over 75% area of tumor was complete filling and 50%-70% area was comparatively complete filling, and the survival rate was encouraging in these two circumstances.

Chung suggested that over-dose lipiodol injection could lead to pulmonary artery embolism when obvious artery-vein shunt exists, especially in hepatic arterial-venous fistula of large HCC. CT can illustrate obvious A-V shunt and provide guidance for therapy. In such cases, lipiodol dose should be decreased and fistula embolized by gelfoam, then correct dose of lipiodol injected to perfuse tumors.

In the first time of therapy, lipiodol dose should be relatively excessive to completely fill in the tumor, because tumor cells can produce the drug resistance with the increase of TACE operation, the artery will be impaired more or less by lipiodol even produce stenosis or obstruction, and finally, the sufficient blood supply of tumor may turn into poor blood supply, meanwhile, the normal hepatic parenchyma may gradually become cirrhosis, or deteriorated from intrinsic cirrhosis, which would bring side effects and even interrupt the treatment.