Biological effects of low-dose-rate irradiation of pancreatic carcinoma cells in vitro using ^(125)I seeds

AIM:To determine the mechanism of the radiationinduced biological effects of 125I seeds on pancreatic carcinoma cells in vitro.METHODS:SW1990 and PANC-1 pancreatic cancer cell lines were cultured in DMEM in a suitable environment.Gray’s model of iodine-125(125I)seed irradiation was used.In vitro,exponential phase SW1990,and PANC-1cells were exposed to 0,2,4,6,and 8 Gy using 125I radioactive seeds,with an initial dose rate of 12.13c Gy/h.A clonogenic survival experiment was performed to observe the ability of the cells to maintain their clonogenic capacity and to form colonies.Cell-cycle and apoptosis analyses were conducted to detect the apoptosis percentage in the SW1990 and PANC-1 cells.DNA synthesis was measured via a tritiated thymidine(3H-Td R)incorporation experiment.After continuous low-dose-rate irradiation with 125I radioactive seeds,the survival fractions at 2 Gy(SF2),percentage apoptosis,and cell cycle phases of the SW1990 and PANC-1 pancreatic cancer cell lines were calculated and compared.RESULTS:The survival fractions of the PANC-1 andSW1990 cells irradiated with 125I seeds decreased exponentially as the dose increased.No significant difference in SF2 was observed between SW1990 and PANC-1 cells(0.766±0.063 vs 0.729±0.045,P<0.05).The 125I seeds induced a higher percentage of apoptosis than that observed in the control in both the SW1990and PANC-1 cells.The rate of apoptosis increased with increasing radiation dosage.The percentage of apoptosis was slightly higher in the SW1990 cells than in the PANC-1 cells.Dose-dependent G2/M cellcycle arrest was observed after 125I seed irradiation,with a peak value at 6 Gy.As the dose increased,the percentage of G2/M cell cycle arrest increased in both cell lines,whereas the rate of DNA incorporation decreased.In the 3H-Td R incorporation experiment,the dosimetry results of both the SW1990 and PANC-1cells decreased as the radiation dose increased,with a minimum at 6 Gy.There were no significant differences in the dosimetry results of the two cell lines when they were exposed to the same dose of radiation.CONCLUSION:The pancreatic cancer cell-killing effects induced by 125I radioactive seeds mainly occurred via apoptosis and G2/M cell cycle arrest.

Percutaneous needle decompression in treatment of malignant small bowel obstruction

AIM:To investigate the efficacy and safety of percutaneous needle decompression in the treatment ofmalignant small bowel obstruction(MSBO).METHODS:A prospective analysis of the clinical data of 52 MSBO patients undergoing percutaneous needle decompression was performed.RESULTS:Percutaneous needle decompression was successful in all 52 patients.Statistically significant differences were observed in symptoms such as vomiting,abdominal distension and abdominal pain before and after treatment(81.6%vs 26.5%,100%vs 8.2%,and 85.7%vs 46.9%,respectively;all P<0.05).The overall significantly improved rate was 19.2%(11/52)and the response rate was 94.2%(49/52)using decompression combined with nasal tube placement,local arterial infusion of chemotherapy and nutritional support.During the one-month follow-up period,puncture-related complications were acceptable.CONCLUSION:Percutaneous needle intestinal decompression is a safe and effective palliative treatment for MSBO.

Combined radiochemotherapy in patients with locally advanced pancreatic cancer: A meta-analysis

AIM:To compare the long-term clinical efficacy of chemotherapy plus radiotherapy(CRT)with that of radiotherapy alone(RT)or chemotherapy alone(CT)for locally advanced pancreatic carcinoma(LAPC).METHODS:Using manual and computer-aided methods,we searched the data through the databases,including PubMed/EmBase/CNKI/CQVIP/China Journals Full Text Database and websites and proceedings of major annual meetings such as ASCO and CSCO.The methodological quality of the included studies was assessed using the Jadad scoring system.Both English and Chinese publications were searched.We collected data from controlled clinical trials on CRT vs RT or CT for LAPC,and conducted a meta-analysis of 15 included studies.Meta-analysis was performed using RevMan4.2Software according to the method recommended by Cochrane Collaboration.RESULTS:Fifteen eligible randomized controlled trials including a total of 1128 patients were screened.Jadad score was 2 in only one article,and 3-4 in the remaining 14 studies.The meta-analysis showed that CRT was superior in the 6-and 12-mo survivals to the RT alone group or CT alone group(P=0.0001 and P=0.02,respectively),whereas the 18-mo survival showed no significant difference(P=0.23).Subgroup analysis showed that the 6-,12-,and 18-mo survivals were not significantly different between the CRT group and CT group(P=0.07,P=0.23,and P=0.91,respectively).Notably,the CRT group had significantly better 6-,12-,and 18-mo survivals than the RT group(all P<0.01).CRT group had significantly more grade 3-4 treatmentrelated hematologic and non-hematologic toxicities than the CT group or RT group(all P<0.01).CONCLUSION:Compared with CT or RT,CRT can benefit the long-term survival of LAPC patients,although it may also increase treatment-related toxicities.