Dosimetry And Efficacy Research Of High Intensity Focused Ultrasound In The Treatment Of Pancreatic Cancer

Pancreatic cancer is a kind of tumor with high malignancy. Generally, It had noobvious symptoms at early stage. when the tumor developed and had obvioussymptoms, It was always at advanced stage, unresectable. Patients with inoperablepancreatic cancer always had poor quality of life, accompanied with cancer-relatedpain, poor tolerance to chemotherapy and radiation therapy, pain relief was low. Highintensity focused ultrasound (HIFU) is a new means of cancer treatment in recentyears. When the high intensity ultrasound focused on the tumor tissues, it wouldmake a high temperature of tissues. Thus the tissues were going to be ablated byfocused ultrasound energy, and the tumor cells were necrosis. HIFU ablation wassuitable for treating a variety of benign and malignant solid tumors,such as livercancer, pancreatic cancer, kidney cancer, breast cancer, bone malignant tumors, softtissue tumors, uterine fibroids, and so on.21patients with advanced pancreatic canceraccepted HIFU ablation in our hospital, we analyzed the HIFU ablation parametersand the changes of tumor markers, pain relief, tumor imaging changes, complications,as well as the survival before and after treatment, discussed the efficacy and safetydosage of HIFU ablation treatment for pancreatic cancer. ObjectiveTo study the efficacy and safe dosage of high intensity focused ultrasound(HIFU) ablation in pancreatic cancer.MethodsFrom November2010to May2013,21patients with advanced pancreatic cancerwere treated by HIFU at the First Affiliated Hospital of Zhengzhou University. Thesepatients who were randomly divided into two groups (10and11patients,respectively), were given a low-power (100W~249W) treatment and high power(250W~350W) treatment. These two groups of21patients received a total of25times of HIFU treatment(3patients received twice of low-power treatment, while1patient received twice of high-power treatment).The two groups were compared byanalyzing the treatment parameters (average power, total treatment time, treatmenttotal energy, treatment volume, etc.) and volume of tumor response as shown onpostoperative imaging(CT or MRI) examinations. Also, the complications, degree ofpain relief, and survival were compared.The energy efficiency factor (EEF) and theablation ratio were calculated. A preliminary study was conducted on the relationshipof ultrasound dose and ablation effect of HIFU treatment for pancreatic cancer.Results1. After HIFU treatment,the patients accepted a CT or MRI enhanced scanwithin1to3months, all patients had varying degrees of pancreatic tumor necrosisand the volume of tumor necrosis gradually reduced. the CT or MRI enhanced scanshowed no enhancement of tumor necrosis, only enhanced with a ring around thetumor remains.2. The EEF of the high-power group (P≥250W) and the low-power group (P<250W) were (10.39±5.71) J/mm3and (21.62±9.81) J/mm3, the former group wassignificantly lower than the latter group (P <0.05); the ablation ratio of thehigh-power group is higher than the low-power group,(91.52±4.18)%versus (51.59±7.66)%respectively, the difference was statistically significant (P <0.01).3. The energy efficiency factor and the ablation volume for the HIFU treatmentshowed a linear trend, and both were negatively correlated (Pearson correlation coefficient r=-0.485, P<0.05).4. In the high-power group,nine of eleven patients were significantly relievedof pain after treatment (82%); In the low-power group,six of ten patients werealleviated of his pain (60%).the difference was statistically significant (P <0.05).5. In the high-power group,the CA19-9decreased in four of ten patients afterHIFU treatment(40%);In the low-power group,the CA19-9decreased in five of ninepatients after HIFU treatment (56%). the difference was not statistically significant (P＞0.05).6. There was no serious complications after the HIFU treatment. after1weekto1month of HIFU treatment, the liver function, kidney function, blood amylase ofpatients were not significantly increased.7. On Kaplan-Meier survival analysis, HIFU treatment of patients withpancreatic cancer,the median survival was8months and9months in the low-powerand high-power group, respectively (Log-rank test χ2=0.05, P=0.944).ConclusionDuring HIFU treatment of patients with pancreatic cancer, if the ultrasoundpower was between250W and350W, there were a higher proportion of tumorablation and pain relief, with no serious complications. Thus, this dose is safe.