Transbronchial Lung Cryobiopsy Is a Better Diagnostic Tool: Study
A recent technique for collecting lung tissue for analysis, called transbronchial lung cryobiopsy, is better than more conventional methods for a definitive sarcoidosis diagnosis, according to a German study.
The study, “Diagnostic Yield of Transbronchial Lung Cryobiopsy Compared to Transbronchial Forceps Biopsy in Patients with Sarcoidosis in a Prospective, Randomized, Multicentre Cross-Over Trial,” was published in the Journal of Clinical Medicine.
Sarcoidosis is marked by the formation of small abnormal lumps or nodules — called granulomas — most commonly in the lungs. The disease is part of a large group of disorders called interstitial lung diseases (ILDs), which cause inflammation and scarring of the lung tissue.
Transbronchial lung cryobiopsy (TBLC) is a recent lung biopsy technique increasingly being used to diagnose ILDs. It involves a flexible tube inserted through the nose or mouth. A small area of lung tissue is frozen and attached to a probe for analysis.
TBLC is deemed superior in diagnosing ILDs to the more conventional transbronchial lung forceps biopsy (TBLF), which uses forceps at the tube’s tip to collect tissue samples and is only able to collect a small tissue sample.
To determine if TBLC is actually superior in diagnosing sarcoidosis, a research team in Germany analyzed data from a multi-center clinical trial (NCT01894113) at University Hospital Tuebingen that compared the effectiveness of TBLC to TBLF in diagnosing ILD patients. Each patient underwent both TBLF and TBLC analysis, conducted in a random order.
Of 359 ILD patients requiring a lung biopsy for diagnosis, 272 had available tissue analysis. A total of 17 patients (nine women, eight men; mean age 44.6) were diagnosed with sarcoidosis. Nine were nonsmokers, four were ex-smokers, and the other four were current smokers.
Among the 272 patients, tissue analysis consistent with sarcoidosis was found in 16 patients (5.9%) when using TBLC compared to seven patients (2.6%) by TBLF.
Among the 17 patients with sarcoidosis, 10 could only have a diagnosis by TBLC. Only in one case was TBLF the single technique able to diagnose sarcoidosis. In the remaining six patients, TBLC and TBLF led to the same findings.
No statistically significant differences were seen between TBLC and TBLF in the number of biopsies required nor in the duration of the procedure. Also, no differences were seen in the size of forceps and probe used.
However, the median biopsy size was more than threefold larger with TBLC compared to TBLF. Also, TBLC led to significantly fewer artifacts — changes due to the technique — compared to TBLF. Specifically, no artifacts were seen in 76.5% of TBLC compared to 23.5% in TBLF.
When considering biopsy size and diagnostic yield, the results supported the diagnosis superiority by the larger biopsy size of TBLC, the researchers noted.
Overall, “diagnosis of sarcoidosis was made significantly more often by TBLC than by TBLF,” they wrote. “The use of TBLC should be considered when sarcoidosis is suspected.”
The investigators mentioned the relatively small number of patients with sarcoidosis as a limitation of the study.