A Prospective Study of Intensity-modified Radiation Therapy in Comparison with Conventional 3D-RT for BR Pancreatic Cancer Patients with Arterial Involvement.

BACKGROUND/AIM: Intensity-modulated radiation therapy (IMRT) is a form of radiation therapy that allows accurate irradiation with reduced damage to surrounding tissues. Here, we analyzed borderline-resectable pancreatic cancer (BRPC) with arterial abutment (BR-A) patients with IMRT as neoadjuvant therapy and performed comparisons with patients with conventional RT to clarify the advantages of IMRT as a neoadjuvant therapy. PATIENTS AND METHODS: Thirty BR-A patients treated at our hospital between January 2012 and December 2015 were divided into two groups: 12 patients underwent conventional 3D-RT before resection (RT group); and 18 patients underwent IMRT before resection (IMRT group). We analyzed safety, tumor resection rate, histological classification of the tumor and overall survival. RESULTS: The R0 rate was 84% for the IMRT group and 83% for the RT group. Local therapeutic effects as assessed by Evans classification showed a higher local control rate in the IMRT group (Grade: 1, 0%; 2a, 25%; 2b, 41.6%; 3, 17%; 4, 8%) than in the RT group (Grade: 1, 17%; 2a, 50%; 2b, 17%; 3, 17%; 4, 0%). The cumulative dose of S1 treatment as adjuvant therapy was much smaller in the RT group (18.3%) compared to that in the IMRT group (57.1%, p=0.047), and with better subsequent overall survival rate (MST 32 months vs. 13.8 months, p=0.0273). CONCLUSION: The IMRT group showed a better control rate than the RT group. The neoadjuvant IMRT has advantages of higher completion rate of adjuvant chemotherapy with better nutritional status and better subsequent overall survival rate (OS).