Pancreatic cancer with gastrointestinal obstruction as an initial symptom

To the Editor: Pancreatic cancer is the fourth leading cause of cancer mortality in the United States [ 1, 2 ]. Risk factors of pancreatic cancer include smoking, family history of chronic pancreatitis, advanced age, male, diabetes mellitus, and obesity [1]. Most of patients have no obvious symptoms in the early stage, and are often diagnosed in the late stage and accompanied by invasion of surrounding tissues and distant metastasis, such as local lymph nodes, liver, lung and peritoneum [ 1, 3 ]. Therefore, the prognosis is poor.

Meta-analysis of robotic and laparoscopic surgery for treatment of rectal cancer

AIM: To conduct a meta-analysis to determine the relative merits of robotic surgery (RS) and laparoscopic surgery (LS) for rectal cancer. METHODS: A literature search was performed to identify comparative studies reporting perioperative outcomes for RS and LS for rectal cancer. Pooled odds ratios and weighted mean differences (WMDs) with 95% confidence intervals (95% CIs) were calculated using either the fixed effects model or random effects model. RESULTS: Eight studies matched the selection criteria and reported on 661 subjects, of whom 268 underwent RS and 393 underwent LS for rectal cancer. Compared the perioperative outcomes of RS with LS, reports of RS indicated favorable outcomes considering conversion(WMD: 0.25; 95% CI: 0.11-0.58; P = 0.001). Meanwhile, operative time (WMD: 27.92, 95% CI: -13.43 to 69.27; P = 0.19); blood loss (WMD: -32.35, 95% CI: -86.19 to 21.50; P = 0.24); days to passing flatus (WMD: -0.18, 95% CI: -0.96 to 0.60; P = 0.65); length of stay (WMD: -0.04; 95% CI: -2.28 to 2.20; P = 0.97); complications (WMD: 1.05; 95% CI: 0.71-1.55; P = 0.82) and pathological details, including lymph nodes harvested (WMD: 0.41, 95% CI: -0.67 to 1.50; P = 0.46), distal resection margin (WMD: -0.35, 95% CI: -1.27 to 0.58; P = 0.46), and positive circumferential resection margin (WMD: 0.54, 95% CI: 0.12-2.39; P = 0.42) were similar between RS and LS. CONCLUSION: RS for rectal cancer is superior to LS in terms of conversion. RS may be an alternative treatment for rectal cancer. Further studies are required.

Expression of cyclooxygenase-2 in gastric cancer and its relation to liver metastasis and long-term prognosis

AIM: To investigate the expression of cyclooxygenase-2(COX-2) in gastric cancer and its relation with the liver metastasis and prognosis.METHODS: Expression of COX-2 mRNA and protein was examined in gastric cancer and its paired substantial normal tissue by semi-quantitative reverse transcriptionpolymerase chain reaction and immunohistochemistry.The relation between COX-2 expression and prognosis was investigated in 195 cases.RESULTS: The expression of COX-2 mRNA in gastric cancer tissue was significantly higher than that in normal tissue in 47 cases (w= 792, P＜0.01). The COX-2 mRNA in pT3-4 tissue expressed higher than that in pT1-2tissue (w = 204, P＜0.05). The positive expression rate of COX-2 protein was 57.9% (113/195). The COX-2expression was significantly related to histological type,lymphnode metastasis, venous invasion and liver metastasis (P＜0.05). No relation was found between COX-2 expression and invasion depth, peritoneal metastasis and International Union against Cancer TNMstage. The multiple regression analysis showed that the COX-2 expression and venous invasion were obviously associated with liver metastasis (P＜0.05). However,there was no significant correlation between COX-2immunoreactivity and prognosis.CONCLUSION: COX-2 may play an important role in the development of gastric cancer, and the over-expression of COX-2 protein may be a high risk factor for liver metastasis.

Primary gastrointestinal stromal tumor of the liver treated with sequential therapy

A 67-year-old female presented with a primary hepatic gastrointestinal stromal tumor that was detected by computed tomography and diagnosed based on histopathological and genetic analyses.The tumor was microscopically composed of spindle cells and epithelioid cells,and immunohistochemistry results showed positive staining for CD117 and CD34expression.A genetic analysis revealed a heterozygous point mutation and deletion in exon 11 of c-KIT.After an R0 resection,imatinib mesylate was administered for 1 year until its use was discontinued due to severe side effects.Two years after the original operation,the tumor recurred in the residual liver and was completely resected again.Imatinib mesylate was administered for 2 years until it was replaced by sunitinib malate because of disease progression.The patient has survived for 53 mo after undergoing a sequential therapy consisting of surgical excision,imatinib and sunitinib.

Progress in the treatment of gastrointestinal stromal tumors

Gastrointestinal stromal tumor(GIST)is a type of tumor that originates from the mesenchymal tissue of the digestive tract and accounts for most interstitial tumors of the gastrointestinal tract.Present studies demonstrate that GIST is mainly driven by a mutated c-KIT or platelet-derived growth factor receptor alpha gene.Histologically,GIST is usually composed of spindle cells,epithelioid cells,or pleomorphic cells in a bundle or diffuse pattern.GIST cells are generally immunohistochemically positive for CD34,CD117,or DOG-1 expression.GIST is similar to interstitial cells of Cajal around the myenteric plexus of the gastrointestinal tract,and both have a positive c-KIT gene,CD117,and CD34 expression.At present,gastroscopy,colonoscopy,computed tomography,nuclear magnetic resonance and other means are the primary means to diagnosis GIST.At the same time,for unidentified GIST,biopsy is also a necessary means of examination.However,for the treatment of gastrointestinal stromal tumors,oral Gleevec and surgery are present primary treatment methods,which is still limited.However,not all patients are suitable for Gleevec.For some gene mutated sites,Gleevec treatment is ineffective.With the increase of cases of gastrointestinal stromal tumors,targeted therapies for GISTs with different gene loci mutations are urgently needed.