title: Continuous Low-dose-rate Irradiation of Iodine-125 Seeds Inhibiting Perineural Invasion in Pancreatic Cancer.
abstract: BACKGROUND
  Perineural invasion (PNI) is a histopathological characteristic of pancreatic cancer (PanCa). The aim of this study was to observe the treatment effect of continuous low-dose-rate (CLDR) irradiation to PNI and assess the PNI-related pain relief caused by iodine-125 ( 125 I) seed implantation.
  
  
  METHODS
  The in vitro PNI model established by co-culture with dorsal root ganglion (DRG) and cancer cells was interfered under 2 and 4 Gy of 125 I seeds CLDR irradiation. The orthotopic models of PNI were established, and 125 I seeds were implanted in tumor. The PNI-related molecules were analyzed. In 30 patients with panCa, the pain relief was assessed using a visual analog scale (VAS). Pain intensity was measured before and 1 week, 2 weeks, and 1, 3, and 6 months after 125 I seed implantation.
  
  
  RESULTS
  The co-culture of DRG and PanCa cells could promote the growth of PanCa cells and DRG neurites. In co-culture groups, the increased number of DRG neurites and pancreatic cells in radiation group was significantly less. In orthotopic models, the PNI-positive rate in radiation and control group was 3/11 and 7/11; meanwhile, the degrees of PNI between radiation and control groups was significant difference (P < 0.05). At week 2, the mean VAS pain score in patients decreased by 50% and significantly improved than the score at baseline (P < 0.05). The pain scores were lower in all patients, and the pain-relieving effect was retained about 3 months.
  
  
  CONCLUSIONS
  The CLDR irradiation could inhibit PNI of PanCa with the value of further study. The CLDR irradiation could do great favor in preventing local recurrence and alleviating pain.
authors.affiliation: Liver Cirrhosis Diagnosis and Therapy Center, 302 Hospital of People's Liberation Army, Beijing 100039, China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Lu
authors.affiliation: Department of Gastroenterology and Hepatology, 307 Hospital of People's Liberation Army, Academy of Military Medical Sciences, Beijing 100071, China.
authors.forename: Teng-Hui
authors.initials: TH
authors.lastname: Dong
authors.affiliation: Department of Gastroenterology and Hepatology, 107 Hospital of People's Liberation Army, Yantai, Shandong 264002, China.
authors.forename: Pei-Ren
authors.initials: PR
authors.lastname: Si
authors.affiliation: Department of Gastroenterology and Hepatology, 307 Hospital of People's Liberation Army, Academy of Military Medical Sciences, Beijing 100071, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Shen
authors.affiliation: Department of Gastroenterology and Hepatology, 307 Hospital of People's Liberation Army, Academy of Military Medical Sciences, Beijing 100071, China.
authors.forename: Yi-Liang
authors.initials: YL
authors.lastname: Bi
authors.affiliation: Department of Gastroenterology and Hepatology, 307 Hospital of People's Liberation Army, Academy of Military Medical Sciences, Beijing 100071, China.
authors.forename: Min
authors.initials: M
authors.lastname: Min
authors.affiliation: Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94143-0912, USA.
authors.forename: Xin
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Gastroenterology and Hepatology, 307 Hospital of People's Liberation Army, Academy of Military Medical Sciences, Beijing 100071, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Liu
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000528:radiation effects; D045744:Cell Line, Tumor; D018920:Coculture Techniques; D004307:Dose-Response Relationship, Radiation; D005727:Ganglia, Spinal / Q000166:cytology; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D051379:Mice; D016513:Mice, SCID; D009364:Neoplasm Recurrence, Local / Q000532:radiotherapy; D010190:Pancreatic Neoplasms / Q000532:radiotherapy*; D051381:Rats
chemical_list: D007457:Iodine Radioisotopes