As a supplement to standard needle aspiration for diagnosing lung lesions, cryobiopsy was no better than forceps biopsy for producing a definite diagnosis in a randomized trial, but the tissue-freezing procedure was less time-consuming and did produce biopsy samples more suitable to molecular testing.

Tested alone, the diagnostic yield was higher with mediastinal cryobiopsy versus transbronchial forceps biopsy (85.7% vs 70.8%, P=0.001). Yet when the two emerging biopsy techniques were combined with traditional endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA), they produced a similar rate of definite diagnosis, at 91.6% and 85.7%, respectively (P=0.106), reported Ye Fan, MD, of Third Military Medical University in Chongqing, China, and colleagues.

However, among the non-small cell lung cancer (NSCLC) patients in the study, all of the samples taken by EBUS-TBNA plus cryobiopsy were suitable for molecular testing, as compared with 89.5% of those with EBUS-TBNA plus forceps biopsy (P=0.036), according to the findings published in Pulmonology.

“Guidelines recommend EBUS-TBNA as the method of choice for accessing the mediastinum, and especially for the detection of lung cancer metastases,” noted Fan and colleagues. “Yet, endoscopy-guided needle aspiration is limited by the small amount of retrieved material that in many cases can only be used for cytologic evaluation, making the diagnosis of mediastinal lesions from non-lung cancer causes challenging.”

In the study, the addition of cryobiopsy increased diagnostic yield for benign diseases over EBUS-TBNA alone (78.7% vs 59.6%, P=0.044), a benefit not seen with forceps biopsy as the supplemental method (66.0% vs 59.6%, P=0.522).

“The exceptional performance of cryosampling in view of its ability to provide the largest mediastinal tissue samples among the minimally invasive endoscopic techniques translated into a superior overall diagnostic yield,” the study authors wrote. “Particularly, cryobiopsy enhances accuracy in the detection of mediastinal metastases, and produces samples more conducive to lung cancer molecular testings, which is consistent with prior observations reported in the literature.”

In terms of safety, no severe complications were observed during the procedures or at 4-week follow-up, with postprocedural pneumothorax detected in 1.3% of patients. The most common adverse event observed was minor bleeding.

From October 2021 to April 2022, Fan and colleagues enrolled and randomized a total of 155 patients at two hospitals in Germany and China. Patients were examined via mediastinal endosonography, then needle aspiration, then with three forceps biopsies and cryobiopsy in a random order.

Two-thirds of the patients were men, just under three-fourths were Asian, about a fourth were white, and the median age was approximately 57 years. Lesion sizes were similar between the cryobiopsy-first and forceps biopsy-first groups.

Mean procedure time for EBUS was 22 minutes. Including cryobiopsy was associated with an additional procedural time of 1.7 minutes versus 3.3 minutes with forceps biopsy (P<0.001).

Overall, a definite diagnosis based on the mediastinal biopsy specimens was achieved for 93% of patients. A majority of the diagnoses were lung cancers (53%), with uncommon tumors or benign disorders accounting for 15% and 31%, respectively.

Subgroup analyses of the two supplemental biopsy methods alone revealed a “substantial advantage in diagnostic accuracy” for common lung cancers favoring cryobiopsy (92.6% vs 77.8%, P=0.008). No significant differences were seen between cryobiopsy and forceps biopsy alone when it came to rare tumors (82.6% vs 65.2%, P=0.179) or benign disorders (74.5% vs 61.7%, P=0.184).

Researchers noted that the “most suspicious” lesions were biopsied during the course of the study, which may have limited findings. Other limitations included the use of 1.5-mm biopsy forceps and that on-site cytology was not performed in order to avoid potential bias.

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