Study of circumferential resection margin in patients with middle and lower rectal carcinoma

AIM: To clarify the relationship between circumferential resection margin status and local and distant recurrence as well as survival of patients with middle and lower rectal carcinoma. The relationship between circumferential resection margin status and clinicopathologic characteristics of middle and lower rectal carcinoma was also evaluated. METHODS: Cancer specimens from 56 patients with middle and lower rectal carcinoma who received total mesorectal excision at the Department of General Surgery of Guangdong Provincial People's Hospital were studied. A large slice technique was used to detect mesorectal metastasis and evaluate circumferential resection margin status. RESULTS: Local recurrence occurred in 12.5% (7 of 56 cases) of patients with middle and lower rectal carcinoma. Distant recurrence occurred in 25% (14 of 56 cases) of patients with middle and lower rectal carcinoma. Twelve patients (21.4%) had positive circumferential resection margin. Local recurrence rate of patients with positive circumferential resection margin was 33.3% (4/12), whereas it was 6.8% (3/44) in those with negative circumferential resection margin (P = 0.014). Distant recurrence was observed in 50% (6/12) of patients with positive circumferential resection margin; conversely, it was 18.2% (8/44) in those with negative circumferential resection margin (P = 0.024). Kaplan-Meier survival analysis showed significant improvements in median survival (32.2 ± 4.1 mo, 95% CI: 24.1-40.4mo vs 23.0 ± 3.5 mo, 95% CI: 16.2-29.8 mo) for circumferential resection margin-negative patients over circumferential resection margin-positive patients (log-rank, P < 0.05). 37% T3 tumors examined were positive for circumferential resection margin, while only 0% T1 tumors and 8.7% T2 tumors were examined as circumferential resection margin. The difference between these three groups was statistically significant (P = 0.021). In 18 cancer specimens with tumor diameter ≥ 5 cm 7 (38.9%) were detected as positive circumferential resection margin, while in 38 cancer specimens with a tumor diameter of < 5 cm only 5 (13.2%) were positive for circumferential resection margin (P = 0.028). CONCLUSION: Our findings indicate that circumferential resection margin involvement is significantly associated with depth of tumor invasion and tumor diameter. The circumferential resection margin status is an important predictor of local and distant recurrence as well as survival of patients with middle and lower rectal carcinoma.

Abdominoperineal excision following preoperative radiotherapy for rectal cancer: Unfavorable prognosis even with negative circumferential resection margin

AIM: To evaluate whether an abdominoperineal excision (APE) is associated with increased local recurrence (LR) and shortened disease-free survival (DFS) in mid-low rectal cancer with a negative circumferential resection margin (CRM).

Development and postnatal neurogenesis in the retina: a comparison between altricial and precocial bird species

The visual system is affected by neurodegenerative diseases caused by the degeneration of specific retinal neurons,the leading cause of irreversible blindness in humans.Throughout vertebrate phylogeny,the retina has two kinds of specialized niches of constitutive neurogenesis:the retinal progenitors located in the circumferential marginal zone and Müller glia.The proliferative activity in the retinal progenitors located in the circumferential marginal zone in precocial birds such as the chicken,the commonest bird model used in developmental and regenerative studies,is very low.This region adds only a few retinal cells to the peripheral edge of the retina during several months after hatching,but does not seem to be involved in retinal regeneration.Müller cells in the chicken retina are not proliferative under physiological conditions,but after acute damage some of them undergo a reprogramming event,dedifferentiating into retinal stem cells and generating new retinal neurons.Therefore,regenerative response after injury occurs with low efficiency in the precocial avian retina.In contrast,it has recently been shown that neurogenesis is intense in the retina of altricial birds at hatching.In particular,abundant proliferative activity is detected both in the circumferential marginal zone and in the outer half of the inner nuclear layer.Therefore,stem cell niches are very active in the retina of altricial birds.Although more extensive research is needed to assess the potential of proliferating cells in the adult retina of altricial birds,it emerges as an attractive model for studying different aspects of neurogenesis and neural regeneration in vertebrates.

Risk factors for local recurrence of middle and lower rectal carcinoma after curative resection

AIM： To explore the risk factors for local recurrence of middle and lower rectal carcinoma after curative resection. METHODS： Specimens of middle and lower rectal carcinoma from 56 patients who received curative resection at the Department of General Surgery of Guangdong Provincial People＇s Hospital were studied. A large slice technique was used to detect mesorectal metastasis and evaluate circumferential resection margin status. The relations between clinicopathologic characteristics, mesorectal metastasis and circumferential resection margin status were identified in patients with local recurrence of middle and lower rectal carcinoma. RESULTS： Local recurrence of middle and lower rectal carcinoma after curative resection occurred in 7 of the 56 patients （12.5%）, and was significantly associated with family history （Х^2= 3.929, P = 0.047）, high CEA level （Х^2 = 4.964, P = 0.026）, cancerous perforation （Х^2 = 8.503, P = 0.004）, tumor differentiation （Х^2 = 9.315, P = 0.009） and vessel cancerous emboli （Х^2 = 11.879, P = 0.001）. In contrast, no significant correlation was found between local recurrence of rectal carcinoma and other variables such as age （Х^2 = 0.506, P = 0.477）, gender （Х^2 = 0.102, Z2 = 0.749）, tumor diameter （Х^2 = 0.421, P = 0.516）,tumor infiltration （Х^2 = 5.052, P = 0.168）, depth of tumor invasion （Х^2 = 4.588, P = 0.101）, lymph node metastases （Х^2 = 3.688, P = 0.055） and TNM staging system （Х^2 = 3.765, P = 0.152）. The local recurrence rate of middle and lower rectal carcinoma was 33.3% （4/12） in patients with positive circumferential resection margin and 6.8% （3/44） in those with negative circumferential resection margin. There was a significant difference between the two groups （Х^2 = 6.061, P = 0.014）. Local recurrence of rectal carcinoma occurred in 6 of 36 patients （16.7%） with mesorectal metastasis, and in 1 of 20 patients （5.0%） without mesorectal metastasis. However, there was no significant difference between the two groups （Х^2 = 1.600, P = 0.206）. CONCLUSION： Family history, high CEA level, cancerous perforation, tumor differentiation, vessel cancerous emboli and circumferential resection margin status are the significant risk factors for local recurrence of middle and lower rectal carcinoma after curative resection. Local recurrence may be more frequent in patients with mesorectal metastasis than in patients without mesorectal metastasis.

Pathological factors affecting gastric adenocarcinoma survival in a Caribbean population from 2000-2010

AIM: To investigate pathological factors related to long term patient survival post surgical management of gas-tric adenocarcinoma in a Caribbean population.METHODS: This is a retrospective, observational study of all patients treated surgically for gastric adenocarci-noma from January 1st 2000 to December 31 st 2010 at The University Hospital of the West Indies, an urban Jamaican hospital. Pathological reports of all gastrecto-my specimens post gastric cancer resection during the specified interval were accessed. Patients with a final diagnosis other than adenocarcinoma, as well as pa-tients having undergone surgery at an external institu-tion were excluded. The clinical records of the selected cohort were reviewed. The following variables were analysed; patient gender, patient age, the number of gastrectomies previous performed by the lead surgeon, the gross anatomical location and appearance of the tumour, the histological appearance of the tumour, infil-tration of the tumour into stomach wall and surround-ing structures, presence of Helicobacter pylori and the presence of gastritis. Patient status as dead vs alive was documented for the end of the interval. The effect of the aforementioned factors on patient survival were analysed using Logrank tests, Cox regression models, Ranksum tests, Kruskal-Wallis tests and Kaplan-Meier curves.RESULTS: A total of 79 patients, 36 males and 43 fe-males, were included. Their median age was 67 years(range 36-86 years). Median survival time from surgery was 70 mo with 40.5% of patients dying before the termination date of the study. Tumours ranged from 0.8 cm in size to encompassing the entire stomach speci-men, with a median tumour size of 6 cm. The median number of nodes removed at surgery was 8 with a maximum of 28. The median number of positive lymph nodes found was 2, with a range of 0 to 22. Patients' median survival time was approximately 70 mo, with 40.5% of the patients in this cohort dying before the terminal date. An increase in the incidence of cardiac tumours was noted compared to the previous 10 year interval(7.9% to 9.1%). Patients who had serosal involvement of the tumour did have a significantly shorter survival than those who did not(P = 0.017). A significant increase in the hazard ratio(HR), 2.424, for patients with circumferential tumours was found(P = 0.044). Via Kaplan-Meier estimates, the presence of venous infiltration as well as involvement of the circum-ferential resection margin were found to be poor prog-nostic markers, decreasing survival at 50 mo by 46.2% and 36.3% respectively. The increased HR for venous infiltration, 2.424, trended toward significant(P = 0.055) Age, size of tumour, number of positive nodes found and total number of lymph nodes removed were not useful predictors of survival. It is noted that the results were mostly negative, that is many tumour character-istics did not indicate any evidence of affecting patient survival. The current sample, with 30 observed events(deaths), would have about 30% power to detect a HR of 2.5.CONCLUSION: This study mirrors pathological factors used for gastric cancer prognostication in other popu-lations. As evaluation continues, a larger cohort will strengthen the significance of observed trends.

Application of Laparoscopic Extralevator Abdominoperineal Excision in Locally Advanced Low Rectal Cancer

Background：When compared with conventional abdominoperineal resection （APR）,extralevator abdominoperineal excision （ELAPE） has been demonstrated to reduce the risk of local recurrence for the treatment of locally advanced low rectal cancer.Combined with the laparoscopic technique,laparoscopic ELAPE （LELAPE） has the potential to reduce invasion and hasten postoperative recovery.In this study,we aim to investigate the advantages of LELAPE in comparison with conventional APR.Methods：From October 2010 to February 2013,23 patients with low rectal cancer （T3-4N0-2M0） underwent LELAPE;while during the same period,25 patients were treated with conventional APR.The patient characteristics,intraoperative data,postoperative complications,and follow-up results were retrospectively compared and analyzed.Results：The basic patient characteristics were similar;but the total operative time for the LELAPE was longer than that of the conventional APR group （P =0.014）.However,the operative time for the perineal portion was comparable between the two groups （P =0.328）.The LELAPE group had less intraoperative blood loss （P =0.022）,a lower bowel perforation rate （P =0.023）,and a positive circumferential margin （P =0.028）.Moreover,the patients,who received the LELAPE,had a lower postoperative Visual Analog Scale,quicker recovery of bowel function （P =0.001）,and a shorter hospital stay （P =0.047）.However,patients in the LELAPE group suffered more chronic perineal pain （P =0.002）,which may be related to the coccygectomy （P =0.033）.Although the metastasis rate and mortality rate were similar between the two groups,the local recurrence rate of the LELAPE group was statistically improved （P =0.047）.Conclusions：When compared with conventional APR,LELAPE has the potential to reduce the risk of local recurrence,and decreases operative invasion for the treatment of locally advanced low rectal cancer.