Endoscopic laser therapy is useful for the treatment of both obstruction and bleeding due to intrinsic lesions of the bowel. Advantages of endoscopic laser therapy are the ability to treat tumors under direct visualization and being widely available [31].
The Neodymium: Yttrium-Aluminum-Garnet (Nd:YAG) is the most commonly used laser and has been found to be safe and effective with success rates as high as 85-95 % [66] . Relief of obstruction is immediate and may be repeated if necessary. Application is fairly simple and can be performed in an outpatient setting without general anesthesia [66, 120]. The Nd:YAG laser works by causing coagulative necrosis or vaporization through optic fibers and is not absorbed by water or blood [3, 120]. The depth of penetration is approximately 4 mm and more controlled than electrocoagulation [120]. Overall,
Table 24.3 Randomized prospective trials evaluating self-expanding metallic stents (SEMS) compared with surgical intervention
Study | Study Period | Site of obstruction | Stent (n) | Surgery (n) | Hospital stay (days) | Morbidity | Primary outcome | Conclusions |
Fiori et al. [115] | 2001-2003 | 8 Sigmoid 14 Rectum | 11 | 11 transverse colostomy | 2.6 Stent 8.1 Surgery (P<0.0001) | 0 % Stent 9.1 % Surgery (P = NS) | Mean time for G1 tract canalization: 1 day Stent 3.1 days Surgery (P<0.0001) | SEMS is an effective alternative to surgery |
Xinopoulos et al. [114] | 1998-2002 | 12 Sigmoid 18 Rectosigmoid | 15 14 stent | 15 stoma | 28 Stent 60 Surgery (P = N/A) | 60 % Stent 13.33 % Surgery (P = N/A) | Efficacy and safety | SEMS is a palliative alternative to colostomy with better quahty of life |
Van Hooft et al. [116] | 2004-2006 | 5 Descending colon 16 Rectosigmoid | 11 10 stent 1 did not develop imminent obstruction and was not stented | 10 6 resection with primary anastomosis 1 moved to stent arm due to myocardial infarction | 12 Stent 11 Surgery (P = .46) | 72 % Stent 10 % Surgery (P<0001) | Survival in good health outside of the hospital | Unexpected high rate of perforation (6 of 11) in the stent arm caused early closure of trial |
Cheung et al. [118] | 2002-2005 | 48 Left-sided colon | 24 | 24 11 Hartmann 11 resection with primary anastomosis | 13.5 Stent 14 Surgery (P = .7) | 8 % Stent 50 % Surgery (P = N/A) | Success of 1-stage operation: 67 % Stent 38 % Surgery (P = .04) | SEMS is a safe and effective bridge to surgery |
Van Hooft et al. [119] | 2007-2009 | 98 Left-sided colon | 47 | 51 12 resection with primary anastomosis | N/A | 53 % Stent 45 % Surgery (P = .43) | Global health status: 63 Stent 61.4 Surgery (P = .36) | Stenting has no clinical advantage to emergency surgery |
Complication rates have been reported to be between 2 and 15 % and primarily due to bleeding and perforation [76, 121]. Palliation is maintained in approximately half of patients surviving 6 months. In patients with circumferential tumors or in patients with pain, Nd:YAG is not useful in palliation [120].
Endoscopic argon plasma coagulation (APC) utilizes ionized argon gas to deliver electrical current and provide both fulgaration and hemostasis [116]. It has been demonstrated in a retrospective trial of 272 patients with obstruction to have an immediate success rate of 85 % and low major complication rate of 2 % [122]. APC causes a more superficial ablation (2-3 mm) thus poses less of a risk of perforation compared to the Nd:YAG laser. However, APC is less effective at relieving obstruction.
With growing interest in utilizing radiofrequency ablation (RFA) for solid tumor destruction including liver and prostate malignancies, investigators have evaluated the use of RFA for colorectal cancers. Vavra et al. performed RFA on 12 patients with rectosigmoid tumors found to be unresectable to evaluate feasibility and safety. In their preliminary study, the authors demonstrate no treatment-related morbidity or mortality [123]. Based on this, more studies will likely be performed to assess the use of RFA in colon and rectal cancers.