What factors affect lymph node yield in surgery for rectal cancer?

OBJECTIVE: The detection of lymph node metastases is of vital importance in patients undergoing excisional surgery for rectal cancer as it provides important prognostic information and facilitates decision-making with regards to adjuvant therapy. It has been suggested that patients in whom only a small number of nodes are present in the excised specimen have a worse prognosis, presumably due to inadequate lymphadenectomy and consequent understaging of the disease. The aim of this study was to determine which factors affect the yield of lymph nodes. METHODS: This was a retrospective study of patients who had undergone a resection for histologically proven adenocarcinoma of the rectum. The total number of lymph nodes identified in the excised specimen was recorded in each case. A multivariate analysis was performed to ascertain whether this number was significantly influenced by any of several variables. RESULTS: A total of 167 patients were studied (M:F ratio 107 : 60, median age 70 years). The median number of lymph nodes contained within the resected specimen was 16 (interquartile range 10-21). On univariate analysis a significantly higher yield of lymph nodes was obtained with tumours in the middle third of the rectum (P=0.007), larger tumours (P < 0.001), more locally advanced tumours according to both pT staging (P=0.001) and Dukes' staging (P=0.020), an increased number of involved nodes (P=0.003) and examination by a specialist histopathologist (P=0.003). On multivariate analysis the only significant variables were tumour size (P=0.021), number of positive nodes (P=0.007) and histopathologist (P=0.021). CONCLUSIONS: The number of lymph nodes identified within the excised specimen in patients undergoing resection of a rectal cancer positively correlates with the size of the tumour and is also dependent on the examining histopathologist. In addition, in node-positive patients the number of involved nodes increases with increasing lymph node yield.

An investigation into the effect of a probiotic on gut immune function in surgical patients.

BACKGROUND: The gut-associated lymphoid tissue (GALT) is an important component of the gut barrier. We have previously demonstrated a significant increase in various parameters of gut immune function in association with bacterial translocation. Animal studies have suggested that the probiotic Lactobacillus plantarum 299v improves the immunological status of the intestinal mucosa. The aim of this study was to determine whether the same is true in humans. METHOD: This was a prospective randomised controlled study, in which immunohistochemical techniques were used to measure the concentrations of plasma cells, IgA positive cells and IgM positive cells in the lamina propria, together with the concentrations of IgA and IgM at the mucosal surface in specimens of normal small bowel obtained from patients undergoing elective abdominal surgery who had consumed an oral preparation containing the probiotic Lactobacillus plantarum 299v (ProViva) during the immediate preoperative period. These were compared with similar specimens obtained from control subjects who did not receive the probiotic. RESULTS: A total of 22 patients were studied (probiotic group n = 11, control group n = 11). The median volume of ProViva consumed was 3250 ml (range 2100-9000 ml), for a median duration of 9 days (range 5-18 days). There were no significant differences between the probiotic and control groups in terms of concentrations of plasma cells, IgA positive cells or IgM positive cells in the lamina propria. There was a significantly higher concentration of IgM at the mucosal surface in the control group (P = 0.02, Fishers Exact test mid P), but no difference in terms of IgA. CONCLUSIONS: The increase in IgA observed in the intestinal mucosa in response to probiotics in animal studies does not occur in humans. The significance of the increase in IgM at the mucosal surface in the controls is unclear.

An investigation into the sensitivities of translocating bacteria to a prophylactic antibiotic regimen.

INTRODUCTION: It is well established that bacterial translocation is associated with a significant increase in septic morbidity. The purpose of this study was to determine the antibiotic sensitivities of translocating bacteria on the basis that this information may influence antibiotic prophylaxis in surgical patients. METHODS: Routine microbiological techniques were used to assess the antibiotic sensitivities of those bacteria cultured from a mesenteric lymph node harvested at laparotomy in a large series of patients. RESULTS: Culture of the mesenteric lymph nodes yielded growth in 51 out of a total of 447 patients studied (11.4%). The isolates from 40 patients, a total of 60 organisms, were available for sensitivity testing. The most common species grown was Escherichia coli (48% of isolates). Thirty-three patients (83%) grew organisms sensitive to the antibiotic prophylaxis used, but there was no significant difference in the incidence of postoperative septic complications between these patients and those in whom resistant bacteria were grown (39% versus 29%, P = 0.64 Fisher's Exact test mid P). CONCLUSIONS: The majority of translocating bacteria are sensitive to the prophylactic antibiotics commonly used in patients undergoing laparotomy. However, the occurrence of postoperative septic morbidity is independent of this variable.

A prospective randomised study of the probiotic Lactobacillus plantarum 299V on indices of gut barrier function in elective surgical patients.

BACKGROUND: Bacterial translocation occurs in surgical patients and may predispose to postoperative septic morbidity. Many factors are thought to influence the prevalence of bacterial translocation, one of which is the composition of the gut microflora. The aim of this prospective and randomised study was to assess the effect of the probiotic Lactobacillus plantarum 299v on the incidence of bacterial translocation, gastric colonisation, and septic complications in elective surgical patients. METHODS: Patients undergoing elective major abdominal surgery were randomised to either a treatment or control group. The treatment group received an oral preparation containing Lactobacillus plantarum 299v (Proviva) for at least one week preoperatively and also in the postoperative period. Bacterial translocation was determined by culture of a mesenteric lymph node and serosal scraping obtained at laparotomy. Gastric colonisation was assessed by microbiological culture of nasogastric aspirates. All postoperative septic complications were recorded. RESULTS: A total of 129 patients completed the study (probiotic group n=64). There was no significant difference between the two groups in terms of bacterial translocation (12% v 12%; p=0.82), gastric colonisation with enteric organisms (11% v 17%; p=0.42), or septic morbidity (13% v 15%; p=0.74). CONCLUSIONS: Administration of Lactobacillus plantarum 299v in elective surgical patients does not influence the rate of bacterial translocation, gastric colonisation, or incidence of postoperative septic morbidity.

Gastric colonisation, intestinal permeability and septic morbidity in acute pancreatitis.

INTRODUCTION: Bacterial translocation (BT) may represent an important cause of septic morbidity in patients with acute pancreatitis. We have previously demonstrated an association between BT, septic morbidity and colonisation of the proximal GI tract. Alterations in intestinal permeability (IP) may also predispose to BT. The aim of this study was to assess the extent of gastric colonisation, measure IP in patients with acute pancreatitis and relate these to both disease severity and septic complications. METHODS: Gastric colonisation was determined by culturing a sample of nasogastric aspirate, and IP was measured using a dual sugar probe technique (lactulose/rhamnose test). Disease severity was assessed according to the modified Glasgow (Imrie) criteria. All septic complications were recorded prospectively. RESULTS: A total of 59 patients were studied (M:F ratio 32:27, median age 66 years, range 18-89), 24 (31%) of whom had severe disease. A nasogastric aspirate was obtained in 56 patients. There was a significantly higher incidence of colonisation with potentially pathogenic enteric bacteria in patients with severe disease compared to those with mild disease (57 vs. 6%, p < 0.001). Septic morbidity occurred in 29% of severe patients and 11% mild patients (p = 0.17). 33% of patients colonised with enteric organisms developed sepsis, compared to 16% with no enteric bacteria in the NG aspirate (p = 0.34). Enteric bacteria caused 77% of the septic complications. Intestinal permeability was neither associated with disease severity nor was it predictive of septic morbidity. CONCLUSIONS: There is significantly higher incidence of gastric colonisation with enteric bacteria in patients with severe acute pancreatitis, but no difference in IP. Enteric bacteria were implicated in the majority of septic complications. These findings support the gut origin of sepsis hypothesis in acute pancreatitis.

Bacterial translocation and immunohistochemical measurement of gut immune function.

AIMS: The local immune response in the small bowel mucosa might play a role in bacterial translocation (BT). The aim of this study was to quantify immune cells and secretory antibodies in the small bowel mucosa, and relate this to BT as assessed by culture of a mesenteric lymph node. METHODS: Immunohistochemical techniques were used to measure the frequency of plasma cells and IgA and IgM positive cells in the lamina propria and semiquantitatively to assess mucosal surface IgA and IgM values in small bowel specimens obtained from 11 patients in whom positive evidence of BT had been identified in a mesenteric lymph node harvested at the time of laparotomy. These were compared with similar specimens obtained from 11 patients in whom a similar lymph node had yielded no growth. RESULTS: BT was associated with a significantly increased median frequency of plasma cells (p < 0.01) and IgA positive cells (p < 0.05) in the lamina propria. The frequency of IgM positive cells was also higher in these patients, although this difference was not significant. In addition, semiquantitatively scored IgA and IgM concentrations at the mucosal surface were both significantly higher in the patients in whom BT had been identified (p = 0.006 and 0.016, respectively). CONCLUSION: Higher numbers of plasma cells and higher IgA and IgM values are present in the small bowel mucosa of patients in whom BT has been shown to occur, suggesting an increased local immune response.

Enteral versus parenteral nutrition: a pragmatic study.

Controversy persists as to the optimal means of providing adjuvant nutritional support. The aim of this study was to compare enteral nutrition (EN) and parenteral nutrition (TPN) in terms of adequacy of nutritional intake, septic and nonseptic morbidity, and mortality. This was a prospective pragmatic study, whereby the route of delivery of nutritional support was determined by the attending clinician's assessment of gastrointestinal function. Patients considered to have inadequate gastrointestinal function were given TPN (group 1), while those deemed to have a functioning gastrointestinal tract received EN (group 2). Patients in whom there was reasonable doubt as to the adequacy of intestinal function were randomized to receive either TPN (group 3) or EN (group 4). The trial setting was a large district general hospital with a dedicated nutrition team. A total of 562 patients were included in the study (331 males; median age 67 y). Gastrointestinal function on entry into the study was considered inadequate in 267 patients who were given TPN (group 1) and adequate in 231 whom received EN (group 2). There was clinical uncertainty about the adequacy of gut function in 64 patients (11.4%) who were randomized to receive either TPN (group 3, 32 patients) or EN (group 4, 32 patients). The incidence of inadequate nutritional intake was significantly higher in group 4 compared with group 3 (78.1% versus 25%, P < 0.001). Complications related to the delivery system and other feed-related morbidity were significantly more frequent in both EN groups compared with the respective TPN groups. EN was associated with a higher overall mortality in both nonrandomized and randomized patients. There were no significant differences observed in the incidences of septic morbidity between patients receiving TPN and those given EN. EN is associated with a higher incidence of inadequate nutritional intake, complications related to the delivery system, and other feed-related morbidity than TPN. There is no evidence from this study to support a difference between the two modalities in terms of septic morbidity. Patients in whom there is reasonable doubt as to the adequacy of gastrointestinal function should be fed by the parenteral route.

Oral dietary supplements in pre- and postoperative surgical patients: a prospective and randomized clinical trial.

It has been suggested that the routine provision of oral dietary supplements (ODS) in postoperative surgical patients is of benefit in terms of morbidity and length of hospital stay. The aim of this study was to evaluate the effects of both pre- and postoperative ODS in patients undergoing an elective laparotomy. Patients requiring elective major gastrointestinal surgery were prospectively randomized into one of four groups: Group I received ODS in addition to normal diet both pre- and postoperatively, Group II were given ODS in the preoperative period only, Group III received ODS only in the postoperative period, and Group IV did not receive any supplements. Assessments of nutritional status, voluntary food intake, weight loss, serum albumin, morbidity and mortality, anxiety and depression, and postoperative activity levels were performed, and comparisons made between the groups. One hundred patients were included in the study. The mean daily energy intake from preoperative ODS was 507 +/- 140 kcal, significantly more than the 252 +/- 195 kcal in the postoperative period (P < 0.001). The postoperative voluntary food intake in patients receiving ODS was not significantly different from that in patients receiving normal diet alone (1090 versus 1268 kcal, 46.2 versus 49.1 g protein, P > 0. 05). All groups demonstrated an overall weight loss, with no significant differences between the groups, and there was no demonstrable effect on clinical outcome. At 6 mo postoperatively there were no differences between the study groups in terms of levels of activity. These results suggest that the routine use of perioperative ODS in well-nourished patients undergoing major gastrointestinal surgery confers no clinical or functional benefit.

Bacterial translocation in patients undergoing abdominal aortic aneurysm repair.

BACKGROUND: Bacterial translocation occurs in humans and is associated with an increased incidence of septic morbidity. The aims of this study were to determine the prevalence of bacterial translocation in patients undergoing open abdominal aortic aneurysm (AAA) repair and to identify any association with postoperative septic complications. METHODS: This was a prospective observational study in which patients undergoing aneurysm repair were assessed for evidence of bacterial translocation by culture of a mesenteric lymph node (MLN), small bowel serosal exudate and thrombus within the aneurysm. All postoperative septic complications were recorded. RESULTS: A total of 51 patients was studied (40 men, 11 women; median age 72 years). Enteric bacteria were isolated from the MLNs of five patients (prevalence of bacterial translocation 10 per cent), one of whom also yielded growth from the serosal exudate. Septic morbidity occurred in four of five patients in whom bacterial translocation was identified, compared with nine of 46 in those without translocation (P = 0.013, Fisher's exact test, mid P). One patient in whom Escherichia coli was grown from the MLN developed an aortoenteric fistula, with a coliform species isolated from the graft. CONCLUSION: This study suggests that bacterial translocation occurs in patients undergoing AAA repair. It is associated with an increased incidence of postoperative septic morbidity and provides a possible mechanism for infection of prosthetic aortic grafts.

Ultrasound-guided Tru-cut biopsy of the breast.

Ultrasound-guided automated Tru-cut needle biopsy may be used as an alternative to fine needle aspiration cytology for the assessment of discrete mass lesions of the breast. This is a retrospective study of 187 biopsies, comparing the results with a final diagnosis obtained from subsequent excision or outpatient follow-up. Biopsies were performed using a spring-loaded gun under ultrasound guidance. Invasive malignancy was demonstrated in 114 biopsies, 98 of which were subjected to surgery, with no false-positives. Twelve biopsies contained 'atypical cells', pre-invasive malignancy or risk factors for invasive carcinoma, ten of which proved to be invasive malignancy on excision. Normal or benign tissue was found in 61 biopsies, but of those that proceeded to excision biopsy, 16 were invasive or in situ carcinoma. The sensitivity of the procedure for detecting significant pathology was 88.7%, and the specificity 100%. When used as part of triple assessment, the sensitivity increases to 97.9%. Ultrasound-guided Tru-cut needle biopsy is a well-tolerated and reliable procedure for providing a tissue diagnosis of malignancy before definitive treatment, and obviating the need for formal excision biopsy of lesions for which there is a low index of suspicion.