[Current surgical management of pulmonary metastases]

Effect of high laser output on the central bronchi and pulmonary artery

A diode-pump Nd:YAG high-power laser (wavelength 1320 nm, power 100 W) is routinely used to surgically remove lung metastases. Even pulmonary lesions in central locations are resectable via this method, yet it also carries a potential risk of damaging the larger bronchi and vessels in the vicinity. Studies investigating the safety of using high-power lasers are lacking. We therefore aimed to examine the direct effects of a 100-watt laser on the bronchi and pulmonary artery at a standard working velocity. From freshly slaughtered pigs, we isolated cylindrical specimens of the trachea, the main and lobar bronchi, and the central pulmonary artery from the both lungs. These specimens were fixed consecutively in rows behind each other on a Styrofoam surface in the laboratory. The laser's handle was clamped into a hydraulic feed unit so that the laser was focused at constant distance perpendicular to the tissue and would move at 10 mm/s over the specimens. The Nd:YAG Laser LIMAX® 120 functioned at a consistent power of 100 W during all the experiments. The lasered specimens were examined macroscopically and histologically for tissue damage. None of the trachea or bronchial walls were perforated. Compared to the pulmonary parenchyma, we observed no vaporization effects-only minor superficial coagulation (with a mean depth of 2.1 ± 0.8 mm). This finding was histologically confirmed in each specimen, which revealed mild superficial coagulation and no damage to the cartilage. In the presence of a residual peribronchial fatty tissue, the laser effect was even attenuated. The pulmonary arteries presented no lumen openings whatsoever, merely a discrete trace of coagulation. The vessel wall revealed increased vacuolization without alteration of the remaining vessel wall. In conclusion, laser resection at 100 W of the central lung areas is safe with respect to airways and blood vessels and the laser output does not need to be reduced when treating these areas.

Endobronchial ultrasound-guided transbronchial needle aspiration is a sensitive method to evaluate patients who should not undergo pulmonary metastasectomy†

OBJECTIVES

Pulmonary metastasectomy is considered an effective treatment in selected patients with extrapulmonary cancer and oligometastatic disease. We know that the presence of mediastinal lymph node metastases reduces survival significantly, but the mediastinum is rarely evaluated before metastasectomy in these patients. We prospectively evaluated how endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) could identify metastases to the mediastinal lymph nodes in patients referred for pulmonary metastasectomy.

METHODS

All patients with extrapulmonary cancer and oligometastatic disease confined to the lungs on positron emission tomography-computed tomography, and who were considered eligible for pulmonary metastasectomy, routinely underwent EBUS-TBNA of the mediastinal lymph nodes. If EBUS-TBNA did not reveal malignant spread, the patient subsequently underwent pulmonary metastasectomy with systematic sampling of mediastinal lymph nodes for histological evaluation.

RESULTS

One hundred and three eligible patients were referred for EBUS-TBNA during a 4-year period. The primary cancers were located in the colon/rectum (n = 64), kidney (n = 16) and other sites (n = 23). EBUS-TBNA sampled 248 lymph nodes and adequate cytology was obtained in 93 patients (90%). EBUS-TBNA found lymph node metastases in 17 patients (16.5%) and during subsequent pulmonary metastasectomy in the remaining 86 patients 1 (1.0%) had a lymph node metastasis. The sensitivity, specificity, NPV and PPV of EBUS-TBNA for diagnosis of mediastinal lymph node metastasis were 94.4, 100, 98.8 and 100%, respectively.

CONCLUSIONS

EBUS-TBNA is a sensitive minimally invasive modality for evaluation of mediastinal lymph node metastases in patients with oligometastatic pulmonary disease. It allows surgeons to select patients who will not benefit from pulmonary metastasectomy.