Factors associated with local recurrence after neoadjuvant chemoradiation with total mesorectal excision for rectal cancer.

BACKGROUND: The purpose of the present study was to investigate risk factors associated with local recurrence in patients with locally advanced rectal cancer who received preoperative chemoradiotherapy in combination with total mesorectal excision (TME). METHODS: Rectal cancer patients who were treated with neoadjuvant chemoradiation with TME were studied. We compared 26 patients who developed local recurrence with 119 recurrence-free patients during the follow-up period. RESULTS: The median follow-up period was 52 months (range: 14-131 months). Based on the use of univariate and multivariate analyses, circumferential margin involvement (p = 0.02), the presence of lymphovascular or perineural invasion (p = 0.02), and positive nodal disease (p = 0.03) were contributing factors for local recurrence. The local recurrence rate was different between ypN(+) patients and ypN(-) patients with more than 12 nodes retrieved (p = 0.01). There was no difference in local recurrence rates between ypN(+) patients and ypN(-) patients with < 12 nodes (p = 0.35) or between ypN(-) patients with < 12 nodes or > or = 12 nodes (p = 0.18). CONCLUSIONS: Patients with circumferential margin involvement, the presence of lymphovascular or perineural invasion, and positive nodal disease should be regarded as a high-risk group. We also determined that lymph node retrieval (< 12 nodes) in patients with node-negative disease was a risk factor for local recurrence.

The prognostic impact of the number of lymph nodes retrieved after neoadjuvant chemoradiotherapy with mesorectal excision for rectal cancer.

BACKGROUND: We aimed to assess factors associated with the number of nodes retrieved and the impact of the number of lymph nodes in rectal cancer patients who underwent neoadjuvant chemoradiation with radical surgery. METHODS: A total of 258 patients were enrolled. Lymph nodes were retrieved from specimens using a manual dissection technique. RESULTS: Of the 258 patients, nine patients had an absence of lymph nodes (ypNx), 150 patients had a node-negative status (ypN(-)) and 99 patients had node-positive disease (ypN(+)). An advanced ypT classification (ypT3,4) and larger tumor (>4 cm) were associated with an increased number of nodes retrieved. The pretreatment CEA level (>5 ng/ml) and ypN(+) classification were significant risk factors for cancer specific and recurrence free survival. There was no significant difference of oncological outcomes among ypNx patients and a subset of ypN(-) patients based on the number of nodes retrieved using three cutoff values (1-11, 12-25, and 25-65 nodes). CONCLUSIONS: In a neoadjuvant setting, ypN(+) disease was an independent risk factor for oncological outcomes. An absence of nodes does not represent an inferior oncological outcome. The number of nodes does not seen to impact survival and recurrence in ypN(-) patients.

The influence of the number of retrieved lymph nodes on staging and survival in patients with stage II and III rectal cancer undergoing tumor-specific mesorectal excision.

OBJECTIVE: This study was designed to determine whether the number of lymph nodes retrieved influence staging and survival in patients with stage II and III rectal cancer that undergo tumor-specific mesorectal excision. SUMMARY BACKGROUND DATA: The prognostic impact of the retrieved nodes has been emphasized in patients with colorectal cancer, but few studies have focused on patients with rectal cancer. METHODS: A total of 900 patients who underwent tumor-specific mesorectal excision with curative intent and adjuvant chemoradiation therapy for stage II and III rectal cancer from January 1989 to December 2006 were analyzed. RESULTS: Cancer-specific survival (CSS) of stage II patients with less than 15 nodes (25th percentile) was not different from stage III patients, but CSS was better in stage II patients with more than 15 nodes. When using cutoff values of the 25th and 50th percentiles (22 and 31 nodes), recurrence-free survival (RFS) was statistically different among subgroups of stage II and III patients. In multivariate analysis, stage II disease with less than 15 nodes retrieved was an adverse factor for CSS and RFS. In Kaplan-Meier survival analysis, using cutoff values, the difference for CSS was not significant with 22 and more nodes and the difference for RFS was not observed with 23 and more nodes. CONCLUSIONS: The number of lymph nodes retrieved is closely associated with survival and recurrence in patients with stage II rectal cancer and, for more accurate prognostic stratification, at least 22 and 23 nodes seem to be necessary, respectively, for CSS and for RFS.

Operative safety and oncologic outcomes of anal sphincter-preserving surgery with mesorectal excision for rectal cancer: 931 consecutive patients treated at a single institution.

BACKGROUND: This study was designed to evaluate the operative safety and long-term oncologic outcomes of sphincter-preserving surgery based on sharp mesorectal excision for rectal cancer. METHODS: Between January 1989 and June 2004, 931 patients underwent sphincter-preserving surgery based on sharp mesorectal excision. The operative safety and oncologic outcomes were assessed for the periods of 1989-1996 (n = 208) and 1997-2004 (n = 723). Total mesorectal excision (TME)-based sphincter-preserving surgery was performed during the period of 1989-1996. A multidisciplinary team approach and tailored mesorectal excision, which is the differential removal of the mesorectum, were our standard treatment for patients with rectal cancer during the period of 1997-2004. RESULTS: The use of preoperative chemoradiation (P < 0.001), ultralow anterior resection with coloanal anastomosis (P = 0.01), diverting stoma (P = 0.001), and <2 cm of a distal resection margin (P = 0.01) were more common during the period of 1997-2004. There were no differences between the two periods with regard to perioperative complications (P = 0.2), such as anastomosis leakage (2.4% vs. 3.6%). Cancer-specific survival rates (79.1% vs. 79.6%, P = 0.7) and local recurrence (8.4% vs. 8.6%, P = 0.99) did not differ significantly for the two periods. CONCLUSIONS: Based on sharp mesorectal excision, operative safety and oncologic outcomes were not compromised by technical advances in sphincter-preserving surgery using tailored mesorectal excision and a shortened distal margin.

Factors associated with anastomotic recurrence after total mesorectal excision in rectal cancer patients.

BACKGROUND: In patients undergoing total mesorectal excision (TME), the clinical variables most relevant to anastomotic recurrence have not been identified. We evaluated factors associated with anastomotic recurrence in patients undergoing TME and the impact of a reduced distal margin on anastomotic recurrence. METHODS: Thirty-eight patients with anastomotic recurrence were compared with 876 patients who received curative rectal cancer surgery. Patients were compared according to: (1) the presence of anastomotic recurrence (recurrence vs. recurrence-free), (2) distal margin length (< or =10 mm vs. >10 mm) and (3) additional treatment (none, adjuvant, or neoadjuvant). The risk factors for anastomotic recurrence were analyzed. RESULTS: In the recurrence group, an advanced T stage (T3 and T4) (P = 0.01) microscopic distal margin involvement (P = 0.002) and an elevated CEA level (>5 ng/ml) (P = 0.04) were more commonly found. The incidence of anastomotic recurrence was not higher in the distal margin < or =10 mm group and did not differ according to additional treatment. The multivariate analysis showed that an advanced T stage (T3 and T4) and microscopic distal margin involvement were risk factors for anastomotic recurrence. CONCLUSION: A distal margin < or =10 mm appears to be acceptable in terms of anastomotic recurrence. Patients with a positive distal margin, on the postoperative pathology, should be considered at high risk for anastomotic recurrence.

Effects of earthworm cast and powdered activated carbon on methane removal capacity of landfill cover soils.

Landfill gases could be vented through a layer of landfill cover soil that could serve as a biofilter to oxidize methane to carbon dioxide and water. Properly managed landfill cover soil layers may reduce atmospheric CH4 emissions from landfills. In the present study, the effects of earthworm cast and powdered activated carbon (PAC) on the CH4 removal capacity of the landfill cover soil was investigated. For this purpose, column and batch tests were conducted using three different materials: typical landfill cover soil, landfill cover soil amended with earthworm cast, and landfill cover soil amended with PAC. The maximum CH4 removal rate of the columns filled with landfill cover soil amended with earthworm cast was 14.6mol m(-2)d(-1), whereas that of the columns filled with typical landfill cover soil was 7.4mol m(-2)d(-1). This result shows that amendment with earthworm cast could stimulate the CH4-oxidizing capacity of landfill cover soil. The CH4 removal rate of the columns filled with landfill cover soil amended with PAC also showed the same removal rate, but the vertical profile of gas concentrations in the columns and the methanotrophic population measured in the microbial assay suggested that the decrease of CH4 concentration in the columns is mainly due to sorption. Based on the results from this study, amendment of landfill cover soil with earthworm cast and PAC could improve its CH4 removal capacity and thus achieve a major reduction in atmospheric CH4 emission as compared with the same landfill cover soil without any amendment.

Evaluation of retinal nerve fiber layer thickness in the area of apparently normal hemifield in glaucomatous eyes with optical coherence tomography.

PURPOSE: The authors investigated the correlation between visual field defects detected by automated perimetry and the thickness of the retinal nerve fiber layer measured with optical coherence tomography, and examined whether there is a decrease in retinal nerve fiber layer thickness in the apparently normal hemifield of glaucomatous eyes. PATIENTS AND METHODS: Forty-one patients with glaucoma and 41 normal control subjects were included in this study. Statistical correlations between the sum of the total deviation of 37 stimuli of each hemifield and the ratio of decrease in retinal nerve fiber layer thickness were evaluated. The statistical difference between the retinal nerve fiber layer thickness of the apparently normal hemifield in glaucomatous eyes and that of the corresponding hemifield in normal subjects was also evaluated. RESULTS: There was a statistically significant correlation in the sum of the total deviation and retinal nerve fiber layer thickness decrease ratio (superior hemifield, P = 0.001; inferior hemifield, P = 0.003). There was no significant decrease in retinal nerve fiber layer thickness in the area that corresponded to the normal visual field in the hemifield defect with respect to the horizontal meridian in glaucomatous eyes (superior side, P = 0.148; inferior side, P = 0.341). CONCLUSIONS: Optical coherence tomography was capable of demonstrating and measuring retinal nerve fiber layer abnormalities. No changes in the retinal nerve fiber layer thickness of the apparently normal hemifield were observed in glaucomatous eyes.