Meta-analysis of sentinel lymph node biopsy after neoadjuvant chemotherapy in patients with initial biopsy-proven node-positive breast cancer.

BACKGROUND: Neoadjuvant chemotherapy for breast cancer has the potential to achieve a pathological complete response in up to 40 per cent of patients, converting disease that was initially node-positive to node-negative. This has raised the question of whether sentinel lymph node biopsy could be an alternative to axillary lymph node dissection in these patients. The aim was to undertake a systematic review and meta-analysis of the accuracy and reliability of sentinel lymph node biopsy after neoadjuvant chemotherapy in patients with initial biopsy-proven node-positive breast cancer. METHODS: A literature search was conducted using PubMed, Ovid MEDLINE, Embase and Web of Science databases up to 30 April 2017. Inclusion criteria for studies were pathological confirmation of initial node-positive disease, and sentinel lymph node biopsy performed after neoadjuvant chemotherapy followed by axillary lymph node dissection. RESULTS: A total of 13 studies met the inclusion criteria and were included in the analysis (1921 patients in total). The pooled estimate of identification rate was 90 (95 per cent c.i. 87 to 93) per cent and the false-negative rate was 14 (11 to 17) per cent. In subgroup analysis, the false-negative rate with use of dual mapping was 11 (6 to 15) per cent, compared with 19 (11 to 27) per cent with single mapping. The false-negative rate was 20 (13 to 27) per cent when one node was removed, 12 (5 to 19) per cent with two nodes removed and 4 (0 to 9) per cent with removal of three or more nodes. CONCLUSION: Sentinel lymph node biopsy after neoadjuvant chemotherapy in patients with biopsy-proven node-positive breast cancer is accurate and reliable, but requires careful patient selection and optimal surgical techniques.

A European survey of bowel preparation in colorectal surgery.

AIM: Meta-analysis has shown that mechanical bowel preparation (MBP) does not improve outcomes in colonic surgery; however, there is uncertainty regarding MBP use in laparoscopic and rectal surgery and the addition of oral antibiotic regimens. The aim of this study was to assess current use of bowel preparation among European surgeons. METHOD: An online survey was circulated to members of the European Society of Coloproctology. Chi-squared analysis was used to compare subgroups. RESULTS: A total of 426 surgeons responded to the survey. MBP is routinely prescribed by 29.6% of respondents prior to colonic surgery and in 77.0% prior to rectal surgery. In the cohort performing > 30% of colorectal operations laparoscopically (n = 294), routine use of MBP in colonic surgery was significantly lower (19.7% vs 51.5%, P < 0.01). Less than 10% prescribe oral antibiotic bowel preparation whereas 96% prescribe perioperative intravenous antibiotics. CONCLUSION: Among the majority of respondents to this survey, MBP is used routinely for rectal operations. For colonic surgery, laparoscopic surgeons have a significantly lower use of MBP. Use of oral antibiotic bowel preparation remains uncommon.

Altered defaecatory behaviour and faecal incontinence in a video-tracked animal model of pudendal neuropathy.

AIM: The aim was to develop a behavioural animal model of faecal continence and assess the effect of retro-uterine balloon inflation (RBI) injury. RBI in the rat causes pudendal neuropathy, a risk factor for obstetric related faecal incontinence in humans. METHOD: Video-tracking of healthy rats (n = 12) in a cage containing a latrine box was used to monitor their defaecatory behaviour index (DBI) over 2 weeks. The DBI (range 0-1) was devised by dividing the defaecation rate (pellets per hour) outside the latrine by that of the whole cage. A score of 0 indicates all pellets were deposited in the latrine. Subsequently, the effects of RBI (n = 19), sham surgery (n = 4) and colostomy (n = 2) were determined by monitoring the DBI for 2 weeks preoperatively and 3 weeks postoperatively. RESULTS: The DBI for healthy rats was 0.1 ± 0.03 with no significant change over 2 weeks (P = 0.71). In the RBI group, 13 of 19 rats (68%) showed no significant change in DBI postoperatively (0.08 ±  -0.05 vs 0.11 ±  -0.07) while in six rats the DBI increased from 0.16 ±  -0.09 to 0.46 ± 0.23. The negative control, sham surgery, did not significantly affect the DBI (0.09 ± 0.06 vs 0.08 ± 0.04, P = 0.14). The positive control, colostomy, increased the DBI from 0.26 ± 0.03 to 0.86 ± 0.08. CONCLUSIONS: This is the first study showing a quantifiable change in defaecatory behaviour following injury in an animal model. This model of pudendal neuropathy affects continence in 32% of rats and provides a basis for research on interventions for incontinence.

Acute lumbosacral nerve stimulation does not affect anorectal motor function in a rodent model.

BACKGROUND: Sacral nerve stimulation has become a first line treatment for fecal incontinence, however, its effect on the motor function of the anorectum is uncertain. The aim of this study was to apply acute lumbosacral nerve stimulation in an animal model and to determine its effect on the external and internal anal sphincter forces, the rectoanal inhibitory and excitatory reflexes, and the slow wave frequency of the internal anal sphincter. METHODS: Lumbosacral nerve stimulation was applied to 16 nulliparous female rats. A novel in vivo preparation was designed to allow simultaneous monitoring of external and internal anal sphincter forces. The effect of rectal distension on the two anal sphincters was also studied. KEY RESULTS: Lumbosacral nerve stimulation delivered at either S1 or L6 in rodents did not affect sphincter forces, rectoanal reflexes or slow wave frequency of anal canal smooth muscle. CONCLUSIONS & INFERENCES: The absence of effect on the motor pathways of continence suggests that the mechanism of action is predominantly on sensory feedback mechanisms from the anorectum, thereby increasing cortical awareness of the pelvic floor.