Diagnosing peRipheral Lung Lesions With CRYO Biopsies

Background:

Lung cancer is currently the leading cause of cancer related deaths world-wide [1]. Approximately 5000 people are diagnosed with lung cancer each year in Denmark [2]. Lung cancer is often detected in late stages of the disease, which are rarely curable and have a poor prognosis [3]. Currently, early stages of lung cancer are often detected incidentally on a computed tomography (CT) scan as a solitary lung lesion [4]. Screening for lung cancer has the possibility to reduce lung cancer mortality, however a screening program will produce a large increase in CT scans with lung lesions [5, 6]. Tissue sampling is one of the corner stones for correctly diagnosing cancer in a patient. Obtaining tissue from the lungs is challenging since the lungs are difficult to access and biopsies comes with risk of complications.

Tissue samples can be acquired either by removing part of the lung surgically, by performing a needle biopsy through the chest wall or by using a bronchoscope (i.e. by endoscopy)-. The latter has the lowest risk of complications, but currently the diagnostic yield is lower than the other two methods. The low risk profile is an advantage in an increasing elderly population, where improvements in the diagnostic capabilities would be of great value to the patients.

Cryo freezing probes enable sampling from the lung parenchyma by freezing a small tissue area which is then extracted via the bronchoscope. The technology was initially invented to provide larger tissue samples for the diagnosis of interstitial lung disease, but may also be of great value for collecting tissue from cancerous disease since cryo biopsies are generally larger and less crushed than traditional biopsies.

Few studies regarding cryo biopsy for sampling cancer in the lungs exists, however initial trials demonstrates higher diagnostic yield and an increase in sufficient material for tumor marker analysis[9, 10].