[Outcomes of laparoscopic surgery after preoperative metallic stent placement for obstructive colorectal cancer].

AIM: To assess the outcomes of preoperative colonic stent placement for obstructive colorectal cancer. PATIENTS AND METHODS: A total of 30 patients with colorectal cancer were treated after preoperative colonic metallic stent placement between July 2012 and March 2014. We reviewed their medical records to assess the usefulness of stent placement and the clinical course. The effects of various clinicopathological variables on post-operative complications were analyzed statistically. RESULTS: Stent insertion was effective in 93% of the 30 patients with obstructive colorectal cancer. Preoperative colonoscopy or enema for proximal colonic survey was possible in 70% of the patients after stent placement; colonic lesions requiring simultaneous resection were noted in 5 patients (24%). The mean interval between stent insertion and operation was 19 days, and 23%of the patients underwent laparoscopic surgery. Statistical analysis revealed that the occurrence of complications was associated with laparoscopic surgery and the amount of operative blood loss. CONCLUSION: Preoperative stent placement in patients with obstructive colorectal cancer is feasible and laparoscopic surgery can be selected after stent placement.

Identification of colorectal cancer patients with tumors carrying the TP53 mutation on the codon 72 proline allele that benefited most from 5-fluorouracil (5-FU) based postoperative chemotherapy.

BACKGROUND: Although postoperative chemotherapy is widely accepted as the standard modality for Dukes' stage C or earlier stage colorectal cancer (CRC) patients, biomarkers to predict those who may benefit from the therapy have not been identified. Previous in vitro and clinical investigations reported that CRC patients with wild-type p53 gene (TP53)-tumors benefit from 5-fluorouracil (5-FU) based chemotherapy, while those with mutated TP53-tumors do not. However, these studies evaluated the mutation-status of TP53 by immunohistochemistry with or without single-strand conformation polymorphism, and the mutation frequency was different from study to study. In addition, the polymorphic status at p53 codon 72, which results in arginine or proline residues (R72P) and is thought to influence the function of the protein significantly, was not examined. METHODS: To evaluate the significance of the TP53 mutation as a molecular marker to predict the prognosis of CRC patients, especially those who received postoperative chemotherapy, we examined the mutation by direct sequencing from fresh CRC tumors and evaluated the R72P polymorphism of the mutated TP53 by a combined mutant allele- and polymorphic allele-specific polymerase chain reaction (PCR). RESULTS: The TP53 mutation occurred in 147 (70%) of 211 Japanese CRC tumors. The mutation was observed in 93 (63%) tumors on the R72 allele and in 54 (37%) tumors on the P72 allele. Although the alterations to TP53 have no prognostic significance for CRC patients overall, we found that Dukes' stage C CRC patients who did not receive postoperative chemotherapy and carried the mutated TP53-R72 showed significantly longer survival times than those with the mutated TP53-P72 when evaluated by overall survival (p = 0.012). CONCLUSION: Using a combined mutant allele- and polymorphic allele-specific PCR, we defined the codon 72 polymorphic status of the TP53 mutated allele in Japanese CRC patients. We raised a possibility that Dukes' stage C colorectal cancer patients with tumors carrying TP53 mutation, especially the P72 allele, benefited from 5-FU based postoperative chemotherapy.