Nd:YAG laser photocoagulation in colorectal adenoma. Evaluation of its safety, usefulness, and efficacy

Therapy Insight: approaching endoscopy in anticoagulated patients

Over the past decade, the application of anticoagulant and antiplatelet agents for various cardiovascular and hematologic conditions has become more widespread. Optimal management of these agents during the periendoscopic period requires consideration, but limited prospective data mean that guidelines have largely relied on expert opinion. Elective procedures should be delayed in patients on temporary anticoagulation therapy (e.g. those with deep vein thrombosis). For procedures considered to have a low risk of bleeding (e.g. diagnostic endoscopy and colonoscopy without polypectomy) there is no need to discontinue or adjust anticoagulation. For procedures with a higher risk of bleeding (e.g. polypectomy and biliary sphincterotomy) an individual approach is required. This approach might include stopping oral anticoagulant therapy with or without the administration of unfractionated heparin or low-molecular-weight heparin for the preprocedure and postprocedure periods, during which the patient's international normalized ratio is in the subtherapeutic range.

Laser photoablation of colorectal adenomas: a 12-year experience

BACKGROUND

We analyze laser photoablation as an alternative treatment of large sessile polyps in inoperable patients.

METHODS

Ninety-four colorectal polyps (mean diameter 3.09 +/- 2.7 cm, range 1-15 cm) were treated using high-energy lasers (Nd:YAG and diode). Grade of dysplasia was low in 51, high in 35, with focally invasive cancer in eight.

RESULTS

After 405 laser sessions (4.3 per polyp) five procedure-related complications were observed: two strictures, two bleedings, and one perforation. The last needed a surgical resection; the others were successfully treated by endoscopic therapy. Fifty-seven polyps (61%) were completely eradicated and the growth was controlled in all but two (98%). No degeneration was found after 28-month follow-up of treated adenomas with low- or high-grade dysplasia. Outcome of treatment was dependent on the dimension and grade of the dysplasia (p < 0.05), but not on the polyps' position (rectum or colon). Relief of rectal bleeding was obtained in 90%, of mucus discharge in 77%, and of tenesmus in 100% of cases.

CONCLUSIONS

Laser photoablation of colonic adenomas can be considered a valid procedure not only to relieve symptoms, but also to control the risk of degeneration in patients unfit for surgery or when surgical treatment is considered excessively invalidating.

Guideline on the management of anticoagulation and antiplatelet therapy for endoscopic procedures

This is one of a series of statements discussing the practice of gastrointestinal endoscopy in common clinical situations. It is intended to aid endoscopists in determining the appropriate use of endoscopic procedures in conjunction with anticoagulation and/or antiplatelet therapy. Guidelines for the appropriate practice of endoscopy are based on critical review of the available data and expert consensus. Controlled clinical studies would be beneficial to clarify some aspects of this statement and revision might be necessary as new data appear. Clinical consideration may justify a course of action at variance from these specific recommendations.

Endoscopic Nd:YAG laser therapy for villous adenomas of the right colon

BACKGROUND

Endoscopic laser therapy is considered an acceptable treatment of benign colorectal adenomas. The aim of our study was to evaluate the efficacy of Nd:YAG laser to ablate right-sided colonic sessile adenomas.

METHODS

Between January 1990 and February 1996, 56 patients underwent laser therapy because of high operative risk or refusal of surgery. Lesions were located as follows: cecum (23), ascending, (15), and hepatic flexure (18). Six patients (10.7%) had multiple polyps in the ascending colon. Histologic examination showed a tubulovillous pattern in 20 (35.7%) and a villous pattern in 36 (64.3%). Low-grade dysplasia was detected in 44 patients (78. 5%) and high-grade dysplasia in 12 (21.4%).

RESULTS

The number of laser sessions ranged between 1 and 6 (median 3) and complete ablation, histologically confirmed, was achieved in 49 cases (87.5%). Seven patients (12.5%) underwent surgery: 2 for incomplete tumor destruction, 3 because of invasive carcinoma on repeated biopsies. Two patients (3.6%) had complications (one perforation of the cecum and one hemorrhage). Follow-up ranged from 6 to 60 months and no recurrences were observed.

CONCLUSION

Laser therapy is an effective method for the destruction of sessile adenomas of the right colon in selected patients.

Radiological modalities in the staging of colorectal tumors: new perspectives for increasing accuracy

The purpose of this study was to evaluate the diagnostic accuracy of contrast-enhanced endorectal MRI for the staging of rectal adenoma versus rectal carcinoma in correlation to findings from biopsy and histopathology. Ten volunteers and 20 patients underwent body-coil and endorectal MRI (1.5T supraconducting unit) using plain, T1-weighted (w) T2-w SE and TSE-w sequences, a dynamic Gd-DTPA enhanced protocol (turboFLASH), and postcontrast T1-w-SE sequences. Histopathological correlation via biopsy (n = 10) and surgical resection (n = 19) were conducted for all patients. An independent, two-observer, reader evaluation was performed and qualitative and quantitative data calculated. In volunteers and all patients endorectal MRI reliably delineated normal wall layers. Rectal adenomas (n = 7) were identified by a visualization of an intact muscularis mucosae, a homogeneous inner structure, and a significant contrast enhancement. T1 carcinomas (n = 4) were best identified in dynamic turboFLASH sequences by delineation of an intact muscularis propria. The visualization of contrast-enhancing tumor tissue was indicative of a T2 carcinoma (n = 4). All T3 (n = 3) and T4 (n = 2) carcinomas were correctly staged on dynamic and static MRI. The endorectal MRI stage agreed with the staging results from pathological study in 16 of 20 (80%) patients. Endorectal surface coil MRI provides reliable data for the preoperative staging and evaluation of rectal lesions.

Lasers in rectosigmoid tumors

Over a 14-year period, 746 patients were treated at the Lille Laser Center for rectosigmoid tumor. Two hundred seventy-two patients were treated for palliation of symptoms from rectosigmoid cancer and 474 patients were treated for a benign rectosigmoid villous adenoma. The immediate success rate and complication rate were 85% and 2%, respectively, for patients with advanced cancer, and 92.8% and 1.8% for those with a villous adenoma. Patients with an advanced cancer remained functionally improved during a 10.1-month average period after initial improvement. The recurrence rate after initial treatment for villous adenomas was 18% during a 29.7-month average follow-up. Immediate results were influenced by reason for treatment, initial symptoms, and circumferential extension for patients with a cancer, and only by circumferential extension for patients with a villous adenoma. Long-term results were influenced by reason for treatment and circumferential extension for patients with cancer, and by reason for treatment, initial histology and localization for patients with a villous adenoma. Laser treatment provided relief of symptoms in inoperable patients with advanced rectosigmoid carcinomas. Because treatment is long and difficult and the cancer rate is high, endoscopic laser should be limited in patients with a circumferential villous adenoma to non-surgical candidates. The risk of complication after surgery (some being fatal) has to be balanced against the risk of undetected carcinoma and the indication for endoscopic laser treatment should be discussed case by case.

Sulindac causes regression of rectal polyps in familial adenomatous polyposis

In familial adenomatous polyposis, sulindac-induced polyp regression has been reported by several authors. In this study, the goal was to confirm these results by a randomized, placebo-controlled, double-blind crossover study in 10 patients with rectal polyps that had been previously treated by colectomy and ileorectal anastomosis. Patients received sulindac, 300 mg/day, or placebo during two 4-month periods separated by a 1-month wash-out phase. One patient was not compliant and was excluded. With sulindac, the authors observed a complete (6 patients) or almost complete (3 patients) regression of the polyps. With placebo, the authors observed an increase (5 patients), no change (2 patients), and a relative decrease (2 patients) in the number of polyps. The difference between sulindac and placebo was statistically significant (P less than 0.01). In biopsy specimens of polyps and normal rectal mucosa of 6 patients, the authors conducted an immunohistochemical study of the cellular proliferation index using the Ki 67 monoclonal antibody (Ki 67 index), at the beginning and at the end of each treatment period. They were not able to show a sulindac-induced modification of the Ki 67 index. The authors conclude that sulindac is effective in inducing the regression of rectal polyps in familial adenomatous polyposis.

Nd:YAG laser therapy for colorectal polyps

Adenomatous polyps are the precursors of most colonic cancers and should be removed and recovered for histological analysis. Removal by endoscopic laser photocoagulation offers a safe alternative to surgery. We report our experience of managing selected colonic polyps by neodymium:yttrium aluminum garnet (Nd:YAG) laser.

Alternative lasers for endoscopic surgery: comparison of pulsed thulium-holmium-chromium:YAG with continuous-wave neodymium:YAG laser for ablation of colonic mucosa

Precise and controllable tissue vaporization is essential for minimizing risk in removal of sessile polyps from the lumen of thin walled gastrointestinal organs such as the colon. We compared the ablative efficiency on canine colonic mucosa of the THC:YAG laser with the clinically employed cw Nd:YAG laser. Fresh canine colon was treated with a progressive dose schedule using each laser at several energy/power densities. Ablation depth was measured on fresh tissue and thermal (non-ablation or coagulative) damage examined histologically. The THC:YAG ablation rates were 13.7 +/- 0.8 and 10.2 +/- 0.4 microns/J at 55 and 85 J/cm2, respectively. The Nd:YAG laser generated 3.7 +/- 0.3, 2.8 +/- 0.1, and 3.6 +/- 0.2 microns/J at 4,460, 5,095, and 5,730 W/cm2, respectively. There was a significant (P less than 0.001) difference among the THC:YAG ablation rates and between the THC:YAG and Nd:YAG ablation rates (ANOVA). The THC:YAG laser craters had significantly less collateral thermal damage than Nd:YAG. The pulsed THC:YAG laser should have an important clinical role since its use could reduce the risk of perforation in endoscopic laser procedures such as the removal of sessile polyps.

The potential and limitations of laser photoablation of colorectal adenomas

Ablation of colorectal adenomas by Nd:YAG laser energy was investigated in 271 patients. Two hundred and forty-one patients, selected because of poor surgical and medical condition or refusal of surgery, presented with incompletely removed polyps or with lesions unsuitable for endoscopic polypectomy. Thirty patients with polyposis coli were treated for rectal stump polyps after subtotal colectomy and ileorectal anastomosis. Because of insufficient follow-up (28) or malignant degeneration (23), full evaluation was possible in 196 colon adenoma and 24 polyposis patients. Complete ablation with histologic confirmation for at least 12 weeks was achieved in 150 (82%) of the 183 colon adenomas. This declined to 141 (77%) because of later recurrences in prolonged follow-up. Treatment of large adenomas was less successful than that of intermediate and small lesions: ultimate ablation in 56, 85, and 93%, respectively. Impressive was the immediate relief in 100 symptomatic elderly patients, who were bothered by frequent diarrhea, excessive mucous discharge, and incontinence. All patients survived despite major complications (7%) that mainly consisted of stenosis and hemorrhage. Rectal stump polyps were eliminated in 20 patients with polyposis coli. The remaining four had an uneventful ileoanal anastomosis for ultimately uncontrollable growth of polyps. Malignancy was discovered in 22 adenoma patients and in 1 polyposis patient. We recommend laser ablation of colorectal adenomas for small and medium-sized polyps, that cannot be removed by endoscopic polypectomy in inoperable patients or in patients refusing operation. Laser treatment for extensive adenomas seems only appropriate for symptomatic relief.

Laser-induced fluorescence spectroscopy of human colonic mucosa. Detection of adenomatous transformation

To evaluate the potential of laser-induced fluorescence spectroscopy for the detection of premalignant lesions of the gastrointestinal tract, the hypothesis that adenomatous transformation of colonic mucosa results in an alteration of laser-induced fluorescence that enables its differentiation from normal or hyperplastic tissue was tested. A fiberoptic catheter coupled to a helium-cadmium laser (325 nm) and an optical multichannel analyzer were used to obtain fluorescence spectra (350-600 nm) from 35 normal colonic specimens and 35 resected adenomatous polyps. A score based on six wavelengths was derived by stepwise multivariate linear regression analysis of the spectra. The mean score (+/- SEM) was + 0.86 +/- 0.06 for normal mucosa and -0.86 +/- 0.06 for adenomatous polyps (P less than 0.001). Spectra from an additional 34 normal specimens, 16 adenomatous polyps, and 16 hyperplastic polyps were prospectively classified with accuracies of 100%, 100%, and 94%, respectively. The mean score for hyperplastic polyps was significantly different from adenomatous (P less than 0.001) but not from normal tissue. Thus, quantitative analysis of fluorescence spectra enables the detection of adenomatous transformation in colonic mucosa.

Endorectal sonography in the management of rectal villous tumours

Thirty-seven patients with rectal villous tumours were investigated by endorectal sonography to assess the integrity of the rectal muscularis propria at the tumour level. In four cases assessment of invasion was impossible. In 24 patients, endosonography revealed an ultrasonically superficial lesion not infiltrating the muscular layer. This was confirmed either, in the case of laser treatment, by the absence of malignant recurrence during the follow-up period or by histological examination after surgical resection. In nine patients, endosonography showed infiltration of the muscular layer. This was histologically confirmed in five operated patients. In the remaining four, laser destruction was performed: in two, a rectal adenocarcinoma was present 3 and 6 months later, respectively. These findings show that endosonography has a place in the management of rectal villous tumours, demonstrating invasive cancer in cases where other forms of assessment were wrongly reassuring.

Endoscopic laser applications in the gastrointestinal tract

The Nd:YAG and, to a lesser degree, the argon laser have become valuable tools for the surgical endoscopist. Over the last 10 years, the impetus for application of these expensive instruments has changed from what the laser can do to what the laser can do better than less expensive technology. Whereas a few controlled randomized studies suggest that the Nd:YAG laser is better than no therapy and equivalent to other heat-producing instruments for control of upper gastrointestinal bleeding, such studies do not exist for other laser applications. Despite the lack of such studies, we remain convinced that, where available, lasers are the instrument of choice for palliation of unresectable mucosal-based cancers, coagulation of arteriovenous malformations, and ablation of certain adenomatous polyps in selected patients. New techniques on the horizon include the use of endoscopic photo-dynamic therapy for treatment of gastrointestinal cancers and endoscopic laser fragmentation of large common bile duct stones. The potential role for a nonthermal "endoscopic scalpel" is questionable because most gastrointestinal tissues are well vascularized; however, a pulsed laser capable of cutting and coagulation, such as the holmium:YAG laser, may be of some value for incisional endoscopic procedures.

Eradication of diminutive polyps: a prospective evaluation of bipolar coagulation versus conventional biopsy removal

Bipolar probe coagulation (BICAP) was evaluated and compared with conventional cold biopsy (CBx) as a potential therapeutic modality for eradication of diminutive colonic polyps (DPs). Seventy-seven and 79 DPs were treated with BICAP and CBx, respectively. Twenty-one percent of the BICAP and 29% of the CBx (p greater than 0.05) group had residual polypoid tissue detected at flexible sigmoidoscopy 3 weeks after treatment. Because of incomplete polyp removal, CBx and BICAP coagulation cannot be recommended as definitive therapies for DPs. Neoplasia was present in 22% of DPs located less than 60 cm from the anus, 73% of proximally located small polyps, and 32% of all DPs. Despite apparent eradication at the time of treatment, the incidence of residual polypoid tissue would suggest the need for critical evaluation of other modalities used to eradicate or remove DPs.

Morphologic and histologic changes in canine temporomandibular joint tissues following arthroscopic guided neodymium:YAG laser exposure

A neodymium:yttrium aluminum garnet (Nd:YAG) laser beam was introduced by a quartz fiber passed arthroscopically into the superior joint space of the temporomandibular joints (TMJ) of five mongrel dogs, with one joint serving as a control without laser wounds. Immediate postoperative death and examination of the disc grossly and histologically revealed different patterns for contact and noncontact burn wounds. The wounds exhibited signs of thermal coagulation necrosis similar to those reported in other tissues. The potential implications of the adaptation of the Nd:YAG laser to TMJ arthroscopic surgery are discussed.

Endoscopic laser treatment for rectosigmoid villous adenoma: factors affecting the results

Endoscopic laser treatment is reported in 264 patients with benign rectosigmoid villous adenomas revealed by biopsy. Patients include 100 who had contraindications to surgery, 60 who had a tumor recurrence after a nonlaser treatment, 101 for whom surgical resection appeared to be too drastic for a tumor found benign on biopsy, and 3 who refused surgery. Two types of lasers were used: the Nd:YAG and the argon laser. In some patients, both lasers were used. Treatment was completed in 226 patients. Total tumor destruction was attained in 92% of them, a carcinoma was detected in 7% on biopsy specimens obtained during laser treatment, and benign villous tissue persisted in 1%. During the average 25.9-mo follow-up period of the patients with total tumor destruction, 13% had a tumor recurrence. Treatment was well-tolerated with no major complications. The circumferential extension of the tumor base was the only factor affecting the duration of treatment, and the rate of complications. The recurrence rate after initial treatment was higher in patients treated for a recurrence after a previous nonlaser treatment than in patients treated only by laser (p = 0.04). It was also higher when the initial histology was low-grade dysplasia than if it was high-grade dysplasia (p = 0.017) and when the tumor was located in the lower or middle rectum as opposed to the upper rectum or sigmoid (p = 0.04). We estimated that the direct cost of laser treatments was 28%-40% of the surgery charges for lesions of identical size in our hospital and 31%-69% at UCLA Center for the Health Sciences. Because treatment is long and difficult and the cancer rate is high, endoscopic laser for patients with a circumferential villous adenoma should be limited to nonsurgical candidates. The risk of a fatal complication after surgery has to be balanced against the risk of undetected carcinoma in the other patients and the indication for endoscopic laser treatment should be discussed case by case.

Snare cautery debridement prior to Nd:YAG photoablation improves treatment efficiency of broad-based adenomas of the colorectum

Forty-six patients who underwent piecemeal resection of large, sessile villous adenomas followed by immediate laser photoablative therapy are presented. In contrast to previously published series utilizing laser alone, prior snare resection of such lesions provides copious tissue for histologic analysis, decreases the amount of residual neoplasm requiring laser treatment, and has the potential to improve treatment efficacy.

A randomized study of a coaxial fiber versus a naked fiber for endoscopic Nd:YAG laser therapy of esophageal and rectal tumors

The aim of the study was to determine whether the number of Nd:YAG laser sessions necessary to produce the maximal endoscopic effect was different with the noncontact method using the coaxial fiber than with the contact method using the naked fiber inserted into the tumor. Over a 6-month period, 40 consecutive patients were treated for esophageal and rectal cancers or for benign tumors too large to be removed with a diathermy snare. All of the patients who were offered this treatment had been assessed as unsuitable for surgery and radiotherapy. Twenty patients were randomly assigned to the coaxial fiber group and 20 patients to the naked fiber group. Before treatment, patients in the two groups were not different with respect to age, sex, kind of tumor, contraindication for surgery and radiotherapy, luminal patency, and tumor circumferential extent. At the end of the treatment, the endoscopic score, the transit score, and the evolution of rectal hemorrhage and mucous secretions were not different between the two groups. The number of treatments required to achieve the maximal endoscopic benefit was 6.7 +/- 4.9 (range, 2 to 20) (median = 5) in the coaxial fiber group and 3.4 +/- 1 (range, 2 to 5) (median = 3) in the naked fiber group (p = 0.01). Treatment tolerance and complications were not different between the two groups, but the financial cost related to the fiber was lower in the naked fiber group than in the coaxial fiber group. Therefore, we recommend the contact method using the naked fiber inserted into the tumor in endoscopic Nd:YAG laser therapy for gastrointestinal tumors.

Laser therapy in the management of benign and malignant tumours in the colon and rectum

Since 1983 the Neodymium-YAG laser has been used endoscopically to treat 93 patients with inoperable colorectal carcinoma and 18 patients with benign sessile adenomas. In an additional 11 patients with colorectal cancer, photodynamic therapy (PDT) has been applied using an argon-pumped dye laser. Objective and subjective measurements of quality of life have shown the beneficial effects of the Nd-YAG laser in the relief of symptoms, and four patients have apparently been rendered disease free. Benign tumours also respond to Nd-YAG ablation but close histological supervision is necessary to detect malignant transformation at an early stage. Although PDT may offer a potential for cure in small inoperable tumours, it seems likely that Nd-YAG laser treatment will remain the laser option of choice for advanced bulky tumours.

Laser surgery in colonic and anorectal lesions

Endoscopic laser therapy for diseases of gastrointestinal tract in general, and lesions of colon, rectum, and anus in particular, is in its infancy. Advances are expected to be made to define those lesions that are amenable to lasers and those that are not. In this process, it is hoped that the relative merits and demerits of the various modes of endoscopic therapy might be brought to light. With the advent of contact Nd:YAG laser technology, it is increasingly realized that such a mode of operation could be used to great advantage in both endoscopic and open surgery related to lower-gastrointestinal tract diseases. Furthermore, contact Nd:YAG laser therapy definitely appears to be efficient and safe and compares favorably with other therapies available. How such an effective modality should be sequenced in combination with other available therapies has yet to be worked out. There is more to be done in this arena, which holds high promises.

Nd-YAG laser photoablation of sessile villous and tubular adenomas of the colorectum

Neodymium (Nd)-YAG laser photoablation treatment was used to treat 46 patients with broad-based villous and tubular adenomas of the colon or rectum. These adenomas were distributed throughout the large bowel, with the majority (72%) located above the peritoneal reflection. Patients received an average of 2.1 treatments per adenoma, with 22 patients (48%) requiring only one treatment. Overall treatment success was achieved in 89% of cases (mean follow-up of 12 months), with four patients undergoing continued therapy. Of the patients who received a full course of treatment, only two (4%) were not taken to complete photoablation. Complications were minimal, and 92% of all laser treatments were done on an outpatient basis. Four patients had documented polyp recurrence that was controlled with additional laser treatment. Two patients with malignant polyps who were not surgical candidates were also treated with the laser, with no tumor recurrence seen at 11 and 14 months. Nd-YAG laser photoablation of large colonic polyps offers a safe, efficient, and cost-effective alternative to standard surgical resection.

Endoscopic laser surgery in the colon and rectum

The first applications of laser energy in the gastrointestinal tract occurred barely a decade ago. Since then, endoscopic laser therapy has become widespread in the management of colonic and rectal disease. Applications have been developed for the palliative therapy of obstructing or bleeding malignancies, for the management of some benign and premalignant mucosal diseases and for certain anatomic problems such as anastomotic strictures. Recurrent bleeding from mucosal vascular lesions can be controlled with laser therapy. Methods for treating anorectal disorders also are evolving. The continuing development of new endoscopic systems for increasing ease of access to the gastrointestinal tract all point to ever-increasing applications for laser therapy in colonic and rectal surgery.

Preliminary evaluation of a pulsed 2.15-micron laser system for fiberoptic endoscopic surgery

There is a need for lasers that are compatible with fiberoptic endoscopes and that provide greater cutting precision than currently can be produced by the widely used Nd:YAG (1.06 micron) laser. Recently available lasers that operate in the 2-micron region fill this need. This laser light energy can be transmitted by low OH- silica fibers and has much less tissue penetration than radiation at 1.06 micron. We have been evaluating a prototype solid state laser system that produces pulses of 2.15 microns light that is delivered by a silica based fiberoptic delivery system with negligible transmission losses. This system is based on a thulium-holmium-chromium doped YAG (Tm-Ho-Cr: YAG) rod that lases at 2.15 micron. The laser does not require cryogenic cooling, toxic gases, or custom utilities and should be practical in a clinical environment. In vivo animal testing of this laser confirms that it provides greater ablating precision than does the Nd:YAG laser at 1.06 micron.

Endoscopic Nd-YAG laser treatment of gastrointestinal polyps in patients with familial polyposis

The introduction of the laser into clinical practice has augmented our options for local control of neoplasias. Herein is presented a preliminary report in the use of laser via endoscopy in selected patients with inherited gastrointestinal polyposis.

Laser ablation and palliation in colorectal malignancy. Results of a multicenter inquiry

The role of laser photocoagulation in the palliative treatment of gastrointestinal tumors was investigated in a multicenter inquiry involving seven laser centers and 181 patients. Patients with colorectal malignancies were divided into three groups: those referred for palliation of obstruction (N = 60), those referred for bleeding (N = 81), and those referred for obstruction and bleeding (N = 40). Good palliation was obtained in 89%, with a complication rate of 9.4% and a laser-related mortality of 1.1%. Tumor response, complication rate, mortality, and duration of survival were less favorable in the group with obstructing tumors when compared to those with bleeding or with bleeding and obstruction. Laser phototherapy should play a role as an alternative to surgery in selected patients with bleeding and/or obstructing colorectal cancer.