Microscope slide with biopsy samples
Microscope slide with biopsy samples

Lung biopsy is an essential diagnostic technique, particularly for lung cancer and a variety of parenchymal lung diseases. While surgical lung biopsy remains the primary method for lung tissue sampling, a new prospective study from the Karl Landsteiner University of Health Sciences Krems shows that transbronchial lung cryobiopsy (TBLC) has a good diagnostic correlation with surgical biopsy, but with an improved safety profile.

In the prospective study, a total of 308 cryobiopsies were performed in 75 patients. The researchers found TBLC resulted in lower mortality compared to surgical lung biopsy. Results of the study are published in Therapeutic Advances in Respiratory Disease.

“For lung tissue, surgical biopsy has been the gold standard,” said Klaus Hackner, senior physician at the University Hospital Krems and first author of the study in an interview with Inside Precision Medicine. But it can be risky for patients, especially the elderly and those with comorbidities, due to anesthesia and the invasive nature of accessing the chest cavity. “But it is much easier to get lung tissue with a transbronchial cryobiopsy,” Hackner noted. While the technique was first developed about 10 years ago, data on its safety has been lacking while it has slowly advanced to be an important method for sampling lung tissue. “It isn’t the gold standard, yet I’m quite sure that it will be in the next guidelines on interstitial lung diseases, since it is safer and easier for the patient.”

With TBLC, a bronchoscope is inserted through the trachea into the lungs. A probe is placed inside the scope with a light and a camera. “We go inside the lung and place the cryoprobe at the particular region of interest,” Hackner explains. Cooled to a temperature of -90 degrees C, the cryoprobe immediate freezes the lung tissue it touches, allowing the user to retrieve frozen lung biopsies of one centimeter in diameter.

While the technique is more applicable to interstitial lung disease where pathologists are evaluating the connective tissue in the lung, TBLC can also be used in cancer. In this study, TBLC revealed that three of the 75 patients had lung carcinomas which Hackner describes as resembling an interstitial lung disease on a CT scan. “But with this technique we found it was cancer,” he said.

A key part of the study involved following patients over time to evaluate the safety and the mortality from TBLC.

“There are possible side effects in this technique compared with other bronchoscopic biopsy techniques,” said Hackner, citing that in their study 20% of patients experienced pneumothorax, or air leakage into the area between the lung and chest wall. Bleeding of the bronchial tubes occurred in about one-third of the cases. No fatal events were observed within 30 days after cryobiopsy, and the 90-day mortality rate was 1.3% (one patient), lower than that of surgical lung biopsy with a 30-day mortality of up to 4.5%. The single death was not related to cryobiopsy but to a progressive lung adenocarcinoma.

“Because of the potential risks, it is very important to take precautions with TBLC,” Hackner added, referring to the need to follow published recommendations about careful patient selection, safety techniques during the procedure to minimize bleeding, and post-interventional observation. The researchers found that reduced baseline lung function increased the risk of pneumothorax and bronchial bleeding. “But if you follow these precautions, the technique itself is certainly safer for the patients and easier to perform.”

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