Laser Therapy for Obstruction and Bleeding

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.

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