A retrospective analysis of survival factors of high intensity focused ultrasound (HIFU) treatment for unresectable pancreatic cancer

Abstract

Objective: To retrospectively evaluate possible impact factors of HIFU treatment outcome for unresectable pancreatic cancer patients.

Patients and methods: A total of 689 patients with unresectable pancreatic cancer were recruited in our center from December 30, 2007 to January 30, 2015. 436 patients with unresectable pancreatic cancers received HIFU treatment; the other 253 patients received non-HIFU treatment. Among these 436 patients, 345 patients received a one-time HIFU treatment, 91 patients received HIFU treatment from 2 to 5 times in the same pancreatic mass; 89 patients received HIFU treatment alone; 347 patients received HIFU-based combined therapies. Complications and overall survivals (OS) data in each group were collected.

Results: The median overall survivals (mOS) in HIFU group and non-HIFU group were 7.1 vs. 5 months (P=0.005): 9.3 vs. 7.3 months (P=0.202) for patients with stage II disease, 8.3 vs. 7.3 months (P=0.783) for patients with stage III disease, and 6.4 vs. 4.2 months (P<0.0001) for patients with stage IV disease, respectively. Furthermore, there was a significant difference between repeated HIFU and one-time HIFU (mOS: 8.6 vs. 6.8 months, P=0.011). Time of HIFU treatment (P=0.0027), chemotherapy (P<0.0001), radiotherapy (P=0.0006), regional intra-arterial chemotherapy (RIAC) (P<0.0001), and stage (P<0.0001) were independent prognostic factors for the patients who received HIFU treatment. Cox analysis on the relative risk of prognostic factors showed that repeated HIFU vs. one-time HIFU (HR=0.729: 95% CI=0.576-0.924), chemotherapy vs. non-chemotherapy (HR=0.664: 95% CI=0.576-0.766), radiotherapy vs. non-radiotherapy (HR=0.580: 95% CI=0.427-0.789), RIAC vs. non-RIAC (HR=0.737: 95% CI=0.648-0.837), and stage (HR=1.386, 95% CI=1.187-1.619) were associated with significantly inferior survival. Overall, adverse events occurred in 23.2% (101/436) in the HIFU group, which included increase of serum or urinary amylase levels, incomplete intestinal obstruction, mild fever, etc. There were no severe adverse events such as skin burns or GI perforation related to HIFU therapy in any of the patients treated.

Conclusion: This retrospective analysis revealed that the use of a multimodal treatment approach (the combined therapy of HIFU, RIAC, and chemotherapy, with or without radiotherapy) could improve survival of patients with unresectable pancreatic cancer, and repeated HIFU presented a survival benefit and did not increase risk.