Prophylactic lateral pelvic lymph node dissection in stage Ⅳ low rectal cancer

AIM To assess the clinical significance of prophylactic lateral pelvic lymph node dissection (LPLND) in stage Ⅳ low rectal cancer.METHODS We selected 71 consecutive stage Ⅳ low rectal cancer patients who underwent primary tumor resection,and enrolled 50 of these 71 patients without clinical LPLN metastasis.The patients had distant metastasis such as liver,lung,peritoneum,and paraaortic LN.Clinical LPLN metastasis was defined as LN with a maximum diameter of 10 mm or more on preoperative pelvic computed tomography scan.All patients underwent primary tumor resection,27 patients underwent total mesorectal excision(TME) with LPLND(LPLND group),and 23 patients underwent only TME(TME group).Bilateral LPLND was performed simultaneously with primary tumor resection in LPLND group.R0 resection of both primary and metastatic sites was achieved in 20 of 50 patients.We evaluated possible prognostic factors for 5-year overall survival (OS),and compared 5-year cumulative local recurrence between the LPLND and TME groups.RESULTS For OS,univariate analyses revealed no significant benefit in the LPLND compared with the TME group (28.7% vs 17.0%,P = 0.523); multivariate analysis revealed that R0 resection was an independent prognostic factor.Regarding cumulative local recurrence,the LPLND group showed no significant benefit compared with TME group (21.4% vs 14.8%,P = 0.833).CONCLUSION Prophylactic LPLND shows no oncological benefits in patients with Stage Ⅳ low rectal cancer without clinical LPLN metastasis.

Aquaporin 8 mRNA expression after intestinal resection in rat

Backgrounds: Aquaporins (AQPs), the mammalian water channels, have been localized in various organs, including the gastrointestinal (GI) tract. We examined AQPs expression in rat models of massive intestineal resection to determine the functions of AQPs in the GI tract. Methods: Female Sprague-Dawley rats (n = 15) underwent 90% resection of the small intestine, and Female Wistar-Kyoto rats (n = 10), received subtotal colectomy, and were sacrificed following the operations. RNase protection assay and quantitative reverse transcription-polymerase chain reaction (RT-PCR) were performed to measure the AQPs mRNA expression in the GI tract. Immunohistochemistry was performed to confirm AQP8 protein expression. Results: AQP8 mRNA expression (mean ± standard error), was enhanced in the jejunum of the short bowel rats at days 7 and 14 (37.6% ± 1.4% and 18.5% ± 2.4%, respectively, p < 0.01). Enhancement of AQP8 mRNA was also observed in the remnant rectum of the subtotal colectomized rats at both days 21 and 42 (116.1% ± 4.5% and 143.3% ± 7.4%, respectively, p < 0.01). Immunohistochemistry demonstrated enhanced AQP8 expression in the remnant rectum of the subtotal colectomized rats. No intensive change was observed with other AQPs in both models. Conclusions: Our results suggest a compensatory role of AQP8 in the maintenance of intestinal fluid balance.