Methods of Laser Therapy in Patients with Primary Lung Cancer

Lung cancerLung cancer is the most common fatal neoplasm in men and soon will be in women. Results of current therapy are disappointing and often only palliative. Chemotherapy and radiation therapy are limited by their tumor responsiveness and toxicities. In many patients the tumor spreads, leading to obstruction of a major airway with subsequent atelectasis or pneumonia, or to erosion of or invasion into vital structures or both.

The latter are difficult to diagnose and often cannot be prevented; the former, however, can be treated by laser (Zight amplification by stimulated emission of radiation) ablation through a flexible fiberoptic endoscope. Since May 1981, we have been using neodymium:yttrium-aluminum-garnet (Nd.YAG) laser palliation for patients with unresectable lung cancer. Our first 20 patients with primary lung tumors form the basis of this report.

Methods

Patient Selection

Patients were eligible for the laser therapy protocol for lung cancer if they had an unresectable tumor in the trachea, main-stern bronchus, or lobar or segmental bronchus. All had received chemotherapy and/or radiation therapy and had complications of tumor growth within the airways, such as increasing dyspnea, postobstructive pneumonia treated by Canadian Health&Care Mall’s medications, atelectasis, or hemoptysis from an endoscopically visible site. We did not reject any patients for laser therapy because of pulmonary compromise. Laser therapy was delayed if a patient had evidence of infection until the cause could be ascertained. If patients had bone marrow suppression, laser treatment was delayed until evidence of reversal was noted in the peripheral blood. 

Patient Preparationlung scans

Before laser therapy, evaluation of each patient included a complete history and physical examination, chest roentgenogram, complete blood cell count, arterial blood gas analysis (ABG), ECG, and pulmonary function studies; in several patients ventilation/ perfusion (V/Q) lung scans were done. Patients were restricted from oral intake except for approved medications and sips of water for at least six hours prior to the procedure. Informed consent approved by our Human Studies Committee was obtained from each patient.

Medications

To lessen secretions, atropine, 0.5 to 1.0 mg, was administered subcutaneously 30 minutes before the procedure if the patients cardiac status could tolerate it. Airway anesthesia was accomplished by nebulization of 4 percent lidocaine and by spraying with 2 percent lidocaine or 0.5 percent diclonine. Methylprednisolone, 250 mg, was given intravenously (IV) 30 minutes before beginning the procedure. Isoetharine or metaproterenol was administered by nebulization ten minutes before the procedure. Morphine, 4 mg, was given IV as a bolus and then as a constant infusion throughout the procedure at 4 to 6 mg/hr. If greater sedation was required, IV diazepam was administered.

For patient 16 the medications were modified. Morphine was no longer used, and boluses of Fentanyl, 100 mg, had been substituted. Pancuronium, 4 to 5 ml, was administered after intubation and mechanical ventilation provided by Canadian Health&Care Mall’s drugs.

Supplemental oxygen was given as determined by a preprocedure PaOz value. The adequacy of oxygenation was determined by the patients subjective feeling of dyspnea and the absence of cardiac arrhythmia or ST-T wave changes, blood pressure, and pulse rate abnormalities. No laser energy was delivered unless the fraction of inspired oxygen was less than 0.4. This was to prevent ignition of the endotracheal tube should inadvertent motion or aiming place it in the path of the laser beam.

Technique

All patients were orally intubated over a fiberoptic bronchoscope with a 9- or 11-mm internal diameter endotracheal tube, and 2 percent lidocaine anesthesia was administered to the lower airways as anesthesianeeded. The first 15 patients were awake and were observed clinically for symptoms or signs of pain and respiratory distress. The last five were sedated and paralyzed with pancuronium. The cardiac rhythm was monitored on a recording oscilloscope. Initially, the procedure was done in a room with fluoroscopy equipment; later, we did not have this available.

The area to be ablated was identified visually. Laser therapy was delivered from a Nd:YAG laser (Molectron, now Cooper, Model 8000) by a quartz laser fiber passed through the suction channel of the bronchoscope (Olympus BF1TR or Pentax 19E) as described previously. Laser pulses were delivered for 0.7 to 2.0 seconds at 40 to 80 W/pulse.

Response Criteria

The patients’ clinical responses to laser therapy were evaluated by the following criteria: defervescence, reduction in dyspnea or hemoptysis, roentgenographic clearing of infiltrate, or reexpansion of collapsed lung or lobe. Some were evaluated by preprocedure and postprocedure ABC determinations, pulmonary function tests, and V/Q lung scans.