Life prognosis of sentinel node navigation surgery for early-stage gastric cancer:Outcome of lymphatic basin dissection

BACKGROUND Lymphatic basin dissection is a sentinel node biopsy method that is specific for gastric cancer.In this method,the dyed lymphatic system is dissected en bloc,and sentinel nodes are identified at the back table(ex vivo).Even with lymphatic basin dissection,blood flow to the residual stomach can be preserved,and functionpreserving curative gastrectomy can be performed.The oncological safety of function-preserving curative gastrectomy combined with lymphatic basin dissection has not yet been fully investigated.We hypothesized that the oncological safety of sentinel node navigation surgery(SNNS)is not inferior to that of the guidelines.AIM To investigate the life prognosis of SNNS for gastric cancer in comparison with guidelines surgery.METHODS This was a retrospective cohort study.Patients were selected from gastric cancer patients who underwent sentinel node biopsy from April 1999 to March 2016.Patients from April 1999 to August 2008 were from the Department of Surgery II,Kanazawa University Hospital,and patients from August 2009 to March 2016 were from the Department of Surgical Oncology,Kanazawa Medical University Hospital.Patients who were diagnosed with gastric cancer,which was preoperatively diagnosed as superficial type(type 0),5 cm or less in length,clinical T1-2 and node negative,and underwent various gastrectomies guided by sentinel node navigation were retrospectively collected.The overall survival(OS)and relapsefree survival(RFS)of these patients(SNNS group)were investigated.Patients with gastric cancer of the same stage and who underwent guidelines gastrectomy with standard nodal dissection were also selected as the control group.RESULTS A total of 239 patients in the SNNS group and 423 patients in the control group were included.Pathological nodal metastasis was observed in 10.5%and 10.4%of the SNNS and control groups,respectively.The diagnostic abilities of sentinel node biopsy were 84%and 98.6%for sensitivity and accuracy,respectively.In the SNNS group,81.6%of patients underwent modified gastrectomy or functionpreserving curative gastrectomy with lymphatic basin dissection,in which the extent of nodal dissection was further reduced compared to the guidelines.The OS rate in the SNNS group was 96.8%at 5 years and was significantly better than 91.3%in the control group(P=0.0014).The RFS rates were equal in both groups.After propensity score matching,there were 231 patients in both groups,and the cumulative recurrence rate was 0.43%at 5 years in the SNNS group and 1.30%in the control group,which was not statistically different.CONCLUSION The oncological safety of patients who undergo gastrectomy guided by sentinel node navigation is not inferior to that of the guidelines surgery.

Evaluation of thermal sprayed coating using ultrasonic inspection by means of bottom echo back reflection

Thermal spraying technique is widely used in various mechanical parts as a surface reforming technique.However,as demand to maintain superior mechanical performance in harsh operating environment increases,the need for non-destructive evaluation method for thermal spray coating becomes more important.For this purpose,we thinned the thickness of the thermal sprayed coating by abrasion with blasting and used ultrasonic inspection by means of bottom echo reflection for effective measurement of abrasion quantity in thermal sprayed coating.The results obtained are summarized as follows.When the thickness of thermal sprayed coating becomes thin,the echo height increases.This is because thermal sprayed coatings absorb ultrasonic energy.Ultrasonic energy absorbed by Al2O3 is smaller compared with Fe-13Cr coating.Thermal sprayed coatings submerged in water have a lower echo height compared with air.As mentioned above,the thermal sprayed coating thickness can be estimated using ultrasonic inspection by means of bottom echo back reflection.