Laser Ablation Of Tumors Research Articles

MP-19.01: The use of KTP laser tumor ablation for treatment of bladder transitional cell carcinoma (initial results)

MP-19.01: The use of KTP laser tumor ablation for treatment of bladder transitional cell carcinoma (initial results)

Impact of delay to nephroureterectomy for patients undergoing ureteroscopic biopsy and laser tumor ablation of upper tract transitional cell carcinoma

Objectives To investigate whether a delay in nephroureterectomy for patients with transitional cell carcinoma of the upper urinary tract owing to ureteroscopic biopsy and/or laser tumor ablation affects postoperative disease status. Methods Of 155 patients diagnosed with upper tract transitional cell carcinoma at our institution from 1993 to 2003, 121 underwent nephroureterectomy. We compared the postoperative disease status of patients who underwent nephroureterectomy on the basis of positive cytology findings and filling defect on contrast imaging (no ureteroscopy; n = 34) to patients who underwent nephroureterectomy after ureteroscopic biopsy (n = 75) and patients who underwent nephroureterectomy after ureteroscopic biopsy and laser tumor ablation (n = 12). Results At a mean follow-up of 38.7 months, 29 (85.3%) of 34 patients who underwent nephroureterectomy on the basis of contrast imaging and urinary cytology alone were disease free compared with 61 (81.3%) of 75 patients who underwent ureteroscopic biopsy before nephroureterectomy ( P = 0.18). The mean time from biopsy to nephroureterectomy for these 75 patients was 28 days, and the mean follow-up after nephroureterectomy was 40.1 months. Finally, 10 (83.3%) of 12 patients who underwent ureteroscopic biopsy and laser tumor ablation before nephroureterectomy were disease free at a mean follow-up of 37.2 months. The mean time from ureteroscopic biopsy to nephroureterectomy in this group was 196 days. No significant difference was found in the postoperative disease status between patients undergoing nephroureterectomy after ablation and those who proceeded to nephroureterectomy after endoscopic biopsy or those who did not undergo ureteroscopy before nephroureterectomy ( P = 0.16). Conclusions Ureteroscopy with biopsy and/or tumor ablation before nephroureterectomy did not adversely affect the postoperative disease status.

Abnormal Selective Cytology Results Predict Recurrence of Upper-Tract Transitional-Cell Carcinoma Treated with Ureteroscopic Laser Ablation

Endoscopic management of transitional-cell carcinoma (TCC) of the upper urinary tract remains associated with a significant rate of recurrence. We evaluated the impact of selective upper-tract cytology findings on tumor recurrence and renal salvage rate after ureteroscopic laser tumor ablation. From 1993 though 2003, 38 patients with upper-tract TCC underwent ureteroscopic laser tumor ablation. Cytology specimens were collected from the upper urinary tract prior to ablation. "Abnormal cytology" was defined as the presence of malignant or atypical cells. Patients with abnormal cytology results were compared with patients with those having negative findings for tumor recurrence and renal salvage rates using the X (2) test. Of the 38 patients, 26 (68.4%) experienced at least one recurrence at a mean follow-up of 37.2 months. Pretreatment upper-tract cytology results were available in 34 of these patients: 17 (50%) were negative, and 17 were abnormal. Sixteen of the patients (94.1%) with abnormal cytology results had tumor recurrence after ablation, compared with 8 of the 17 (47.1%) with negative cytology findings (P = 0.0026). Twelve patients (31.5%) underwent nephroureterectomy during follow-up: 8 of the 17 (47.1%) with abnormal cytology, and 4 of the 17 (23.5%) with negative cytology (P = 0.15). Abnormal selective cytology results were associated with a significantly higher rate of tumor recurrence and a trend toward increased renal loss in patients with upper-tract TCC treated with ureteroscopic ablation. These findings suggest a prognostic value for upper-tract cytology analysis in patients undergoing endoscopic therapy.

25: Delay in time to Nephroureterectomy for Patients Undergoing Ureteroscopic Biopsy and Laser Tumor Ablation of Upper Tract Transitional Cell Carcinoma Does not Impact Postoperative Disease Status

25: Delay in time to Nephroureterectomy for Patients Undergoing Ureteroscopic Biopsy and Laser Tumor Ablation of Upper Tract Transitional Cell Carcinoma Does not Impact Postoperative Disease Status

Pathogenesis of systemic air embolism during bronchoscopic Nd

Background. The occurrence of systemic air embolism during bronchoscopic neodymium:yttrium-aluminum garnet laser operations has been suspected. Here we describe its mechanism. Methods. Two patients with embolic cardiac and neurologic complications after bronchoscopic neodymium: yttrium-aluminum garnet laser tumor ablation are described. A subsequent third patient was monitored for intracardiac and aortic air by transesophageal echocardiography. A review of the literature and safety recommendations are discussed. Results. The appearance of systemic air emboli was related to the use of the laser fiber air coolant at high flow and resolved by decreasing the air flow. The presence of intracardiac and aortic air was associated with hypotension and inferior ischemic electrocardiographic changes. Conclusions. Systemic air embolism during bronchoscopic laser operations is a potentially catastrophic complication and is related to the use of gas-cooled laser fibers and contact probes. We recommend using the noncontact mode whenever possible and maintaining the coaxial coolant air flow at the minimum level or using a fluid coolant if contact is necessary.

Pathogenesis of Systemic Air Embolism During Bronchoscopic Nd:YAG Laser Operations

Background. The occurrence of systemic air embolism during bronchoscopic neodymium:yttrium-aluminum garnet laser operations has been suspected. Here we describe its mechanism. Methods. Two patients with embolic cardiac and neurologic complications after bronchoscopic neodymium:yttrium-aluminum garnet laser tumor ablation are described. A subsequent third patient was monitored for intracardiac and aortic air by transesophageal echocardiography. A review of the literature and safety recommendations are discussed. Results. The appearance of systemic air emboli was related to the use of the laser fiber air coolant at high flow and resolved by decreasing the air flow. The presence of intracardiac and aortic air was associated with hypotension and inferior ischemic electrocardiographic changes. Conclusions. Systemic air embolism during bronchoscopic laser operations is a potentially catastrophic complication and is related to the use of gas-cooled laser fibers and contact probes. We recommend using the noncontact mode whenever possible and maintaining the coaxial coolant air flow at the minimum level or using a fluid coolant if contact is necessary.

Monoclonal antibody-coated magnetite particles as contrast agents for MR imaging and laser therapy of human tumors.

Attempts to improve human tumor detection by non-radioactive magnetic resonance techniques have led several investigators to develop antibody-linked paramagnetic contrast agents. Initial studies focused on gadolinium conjugated to monoclonal antibodies. However, very high levels of this contrast agent were needed to significantly reduce proton relaxation times and obtain improved MR images. The use of magnetite (Fe 3O 4) as an MR contrast agent provides a magnetic moment that is approximately one order of magnitude larger than gadolinium. In this study monoclonal antibodies 44 x 14 (specific for squamous cell carcinoma) and 436G10 (specific for melanoma) were obtained from ammonium sulfate precipitation of tumor ascitic fluid. Equal volumes of magnetite solution (1.87 mg Fe/ml) and antibody solution 44 x 14 (5.24 mg protein/ml) and 436G10 (0.64 mg protein/ml) were mixed and sonicated. The 44 x 14-magnetite and 436G10-magnetite solutions were then added to equal volumes of M20 and P3 squamous cell carcinoma cell lines. T1 and T2 values were obtained on a Praxis II NMR spectrometer equipped with a 10 mm probe and 0.25 Tesla permanent magnet. The T2 relaxation times of the magnetite-antibody-cell mixtures were 31 ms with an R = 0.985 for both experimental samples. Our results demonstrate a significant decrease in T2 by binding of the magnetite-coated antibodies to these melanoma and carcinoma cells in vitro. The possibility of detecting subclinical local and metastatic disease with magnetite linked to monoclonal antibodies followed by MRI guided laser tumor ablation therapy may render this technique clinically attractive for treatment of deep-seated tumors.

Electrocoagulation for adenocarcinoma of the low rectum.

Cancers of the distal rectum (less than 7.5 cm from the anal verge) that are freely mobile, moderately well or well differentiated, less than 4 cm in size, limited to the bowel wall, and without evidence of metastasis should be considered candidates for treatment with electrocoagulation for cure. Tumor cell ploidy and evaluation with intrarectal ultrasound may in the future add additional useful information with regard to patient selection. Electrocoagulation and laser ablation of tumors may also be useful modalities for palliation of patients with metastatic disease or who are not candidates for curative surgery.

Obstructing tumors of the subglottic larynx and cervical trachea: airway management and treatment.

A series of 11 patients presenting with airway obstruction secondary to tumors involving the subglottic larynx and cervical trachea was treated with either carbon dioxide or neodymium:yttrium aluminum garnet laser tumor ablation. Choice of ventilation varied according to the site of airway obstruction: Venturi jet with ventilation laryngoscope for glottic and subglottic tumors and a specially designed ventilation laser fiber tracheoscope for tumors obstructing the cervical trachea. All patients subsequently had definitive treatment of the tumor and were relieved of the compromised airway. No complications associated with ventilation and treatment techniques were recorded.