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DOI: 10.1055/s-0032-1326404
Emergency management of acute obstructed left-sided colon cancer: loops, stents or tubes?
Publikationsverlauf
Publikationsdatum:
26. März 2013 (online)
Emergency presentation of colorectal cancer (CRC) occurs in up to 20 % – 25 % of patients, most often as an obstruction (e. g. with clinical picture of colon ileus) or as a perforation (e. g. with clinical picture of peritonitis and sepsis). Either situation represents a challenge for the treating surgeon and is associated with inferior short- and long-term outcomes for the patient [1] [2] [3]. The perioperative and 30-day mortality are increased by up to five times for emergency surgery, and mortality is reported to be over 40 % for the oldest age groups [2]. Emergency surgery would have to be performed as a two- or three-staged procedure depending on the clinical scenario; many patients would receive a permanent stoma, and associated morbidity at time of a temporary stoma take-down should be considered. However, the goal of obtaining an oncologically sound procedure aimed at cure is the prerequisite for each individual patient and this should not be compromised. In the palliative setting, stent placement as a minimally invasive procedure with the aim of symptom relief has demonstrated good short- and long-term effects [4].
As emergency surgery for an obstructed left-sided colon cancer is associated with inferior outcomes from the start, the principle of creating a bridge from the emergency setting to potential elective management (or, at least, “semi-elective”) has been a seductive step to improve outcomes. The employment of colonic self-expanding metal stents (SEMS) to regain continuity in the large-bowel lumen, decompress the colon, and thus create an opportunity for planned surgery after appropriate resuscitation and adequate imaging for staging, has been a temporary appealing exercise among endoscopy enthusiasts. However, although a number of case series have produced positive technical and clinical success rates of over 90 % and the average perforation rate was given at 4 % in several reports, three [5] [6] [7] of four randomized clinical trials have been stopped prematurely due to an unexpected high rate of technical failures and perforation rates exceeding those reported in the past. The Dutch stent-1 trial [5] was stopped prematurely due to a high perforation rate of 13 % and clinical success of 70 %. A systematic review found technical success to be 71 %, clinical success to be 69 %, and a perforation rate of 7 % among randomized controlled trials (RCTs) evaluating SEMS [8]. A number of potential confounders have been suggested to explain the findings from these trials: the level of experience of the endoscopists (too little experience in the hospitals included); the type of stent used (the majority of perforations have been caused by the Wallflex stent); and, the criteria for patient inclusion (complete or partial tumor occlusion). However, the perforation rate is still not negligible, nor is the concern for silent or micro-perforations that may affect the oncological course of the disease. In addition, the dissemination of circulating tumor cells with stent insertion cannot be ignored [9], nor can the incidental finding of increased perineural invasion (a poor prognosticator) in the stented group [10].
As such, the idea of creating a “bridge to surgery” by employment of SEMS for obstructing colon cancer has thus been applauded, disputed, and refuted in the course of the past decade. The evidence in the literature is fraught by a large number of case series with small sample sizes. Consequently, the past attempts at systematic review and meta-analyses have produced only modest levels of aggregated information with a high degree of bias, as most included studies were retrospective in design. In contrast, three recent meta-analyses on the published RCTs available to date [8] [11] [12] have concluded that there is no benefit of stents over emergency surgery. As such, the landscape has changed for performing clinical stent placement and the design of clinical studies is implicated [13] [14].
Set against this background, the current issue of Endoscopy includes a study from Yamada et al. [15] on an alternative to SEMS decompression, namely the use of a transanal tube (Dennis colorectal tube; Covidien, Tokyo, Japan) for preoperative decompression before surgery. The experience has accumulated because the Japanese Ministry of Health did not approve (or reimburse) the use of SEMS until 2011, and the use of the Dennis colorectal tube has thus been a pragmatic alternative.
In the series by Yamada, out of 1142 patients with CRC who underwent surgery over a 5-year period, 92 (8 %) had acute colorectal obstruction, of which 66 were located in the distal colon and eligible for attempt at tube decompression. Of these, 62 (94 %) had a tube placed, but 5 (8 %) had to undergo urgent operation due to perforations or symptoms thereof. The clinical success (defined as numbers going on to elective surgery) was thus 86 %. The arbitrarily chosen end point of the number of patients having a laparoscopically assisted colectomy compared with open surgery does not appear to be a crucial argument as the oncological outcomes (which is the only outcome in the long-term interest of the patient) are unlikely to be influenced by this approach in itself.
The use of transanal tubes for decompression is not new, but reports are scarce outside of Asia [16]. In fact, the Dennis colorectal tube is not commercially available outside of Japan, although alternatives are available in Germany [17]. The common features of the reports on decompression tubes are the retrospective design, consecutive case series, low numbers, and descriptive nature. It is thus tempting to regard the emerging reports on this “novel” device as a repetition of the accumulated past reports of SEMS, which through the increasing case series have now culminated in a few RCTs showing no true benefit and real potential for harm with the use of SEMS.
The question then arises whether transanal tubes really represent progress or are just a variation on the SEMS experience. From a safety perspective, the perforation rate appears to be in the same range as that reported for SEMS [8]. The high technical success rate may require expertise and trained personnel, as it does for SEMS, for real-life 24 – 7-365 availability. The costs may be lower for the Dennis colorectal tube compared with SEMS, but availability may be restricted by product distribution globally. The persistence of clinical success rates can only be realized by good prospective data and preferably RCTs.
In the era of personalized medicine, the potential benefits and harms should be weighed in every individual case, but practice should be based on the best collective evidence available. The creation of society guidelines [18] is currently hampered by the low-grade evidence available for management of patients with obstructed CRC. In finding the best clinical pathway for patients with obstructed CRC, we should aim at gathering the highest possible evidence by sound design of prospective trials, preferably with a randomized design. In the meantime, emergency open surgery as a staged procedure should not be considered a failure, but a valid option in these patients.