As radiography detects more lung nodules, more clinicians are likely counseling patients regarding consideration of nodule biopsies. Patients, meanwhile, have increased access to medical information through the internet, and an increasing concern we hear is fear of tumor dissemination through tissue sampling or resection. Some patients may not express their fears to clinicians, while others may have a frank hesitation to pursue biopsy. As clinicians, it’s helpful to understand available data. While tumor dissemination during biopsy is biologically plausible, the clinical risk of tumor dissemination is exceedingly low.
Current evidence of TTNB
The mechanism of pleural seeding with transthoracic needle biopsy (TTNB) is the unintentional displacement of tumor cells from the tumor along the needle’s tract through the chest wall and lung. This rarely occurs. A large multicenter retrospective study reported six cases among 9,783 TTNBs, an incidence of approximately 0.06%.1
More recent evidence suggests that TTNB may be associated with an increased risk of subsequent ipsilateral pleural recurrence, either alone or with metastases.2 However, this association does not establish causation that biopsy caused tumor spread. Possible explanations for recurrences may include any or all of the following:
- Tumor biology: Aggressive tumors may be more likely to recur regardless of biopsy.
- Undetected disease: Microscopic pleural deposits may have been present at initial staging.
- Surgical factors: Tumor manipulation may affect recurrence risk.
- Patient differences: Baseline clinical or tumor characteristics may differ between groups.
- Residual confounding: Other unmeasured factors may have influenced outcomes.
Pleural recurrence should not automatically be interpreted as needle-tract seeding. One study found no significant difference in intraoperative pleural-lavage cytology between patients with primary lung cancer who did and did not undergo preoperative TTNB over a median period of 20 months.3 These findings support a minimal risk of tumor seeding with TTNB. To date, no procedural modifications to reduce the risk of needle-tract pleural recurrence have been validated.4
Bronchoscopic biopsy: A different approach
Bronchoscopic biopsy avoids the chest wall and pleural space entirely. Consequently, it is generally considered to have a lower biological potential for pleural implantation than TTNB. However, it is not without theoretical risk. Malignant cells could, in theory, be displaced along the bronchial tract or introduced into adjacent airways, vasculature, or lymphatics during biopsy.
This form of airway implantation is exceptionally rare. A recent review identified only four cases of tumor seeding following transbronchial biopsy.5 As with TTNB, the evidence does not establish causality; it is often difficult to distinguish true implantation from natural disease progression or previously undetected multifocal spread. Bronchoscopic seeding risk may be minimized by limiting tissue trauma, maintaining meticulous hemostasis, and using rapid onsite evaluation, where available, to avoid unnecessary additional biopsies to minimize tumor seeding.5
As noted in recent comparative research, navigational bronchoscopy was noninferior to TTNB for tissue diagnosis and may denote an overall better safety profile in experienced centers.6 The limited data seem to suggest bronchoscopy may have a lower rate of tumor seeding and is possibly safer than TTNB. The choice of procedure, however, should always be guided by lesion location, patient preference, and overall procedural feasibility.
Surgical resection
The risk of seeding during surgical resection remains a subject of ongoing discussion. A primary clinical challenge is distinguishing between pre-existing metastatic spread to the pleura and iatrogenic dissemination caused by surgical manipulation. Importantly, mesothelioma has been associated with a higher rate of tract dissemination—with studies illustrating significant rates of tumor seeding following procedures like pleurectomy/decortication as high as nearly 25% (this phenomenon is distinct in its frequency compared with other lung malignancies).7
Thymomas also have a higher than usual risk for pleural seeding with needle biopsy. National Comprehensive Cancer Network guidelines recommend surgical resection over TTNB for suspected thymomas.8 In general, for nonmesothelioma thoracic cancers, clinical evidence suggests that iatrogenic pleural seeding following surgical biopsy or resection is an exceedingly rare event.
The bottom line
TTNB, bronchoscopic, and surgical interventions carry a minuscule risk of dissemination. When discussing care plans with a patient, it is important to acknowledge their fears while also reassuring them with confidence that tumor seeding is rare. Addressing these concerns openly can build trust and support informed decisions about care.
References
1. Tomiyama N, Yasuhara Y, Nakajima Y, et al. CT-guided needle biopsy of lung lesions: a survey of severe complication based on 9783 biopsies in Japan. Eur J Radiol. 2006;59(1):60-64. doi:10.1016/j.ejrad.2006.02.001
2. Hong H, Hahn S, Matsuguma H, et al. Pleural recurrence after transthoracic needle lung biopsy in stage I lung cancer: a systematic review and individual patient-level meta-analysis. Thorax. 2021;76(6):582-590. doi:10.1136/thoraxjnl-2020-216492
3. Sano Y, Date H, Toyooka S, et al. Percutaneous computed tomography-guided lung biopsy and pleural dissemination: an assessment by intraoperative pleural lavage cytology. Cancer. 2009;115(23):5526-5533. doi:10.1002/cncr.24620
4. Sridhar S, Ahn HG, Ebrahimzadeh S, Tang F, Elicker B. Evidence-based approach to transthoracic needle biopsy: procedural techniques, risks, and controversies. Radiographics. 2025;45(9):e240094. doi:10.1148/rg.240094
5. Prabhu Prasad NC. Tumour seeding after transbronchial biopsy: mechanisms, clinical implications, and prevention strategies – a narrative review. Respir Med. 2026;256:108805. doi:10.1016/j.rmed.2026.108805
6. Lentz RJ, Frederick-Dyer K, Planz VB, et al. Navigational bronchoscopy or transthoracic needle biopsy for lung nodules. N Engl J Med. 2025;392(21):2100-2112. doi:10.1056/NEJMoa2414059
7. Lapidot M, Mazzola E, Bueno R. Malignant local seeding in procedure tracts of pleural mesothelioma: incidence and novel risk factors in 308 patients. Cancers (Basel). 2025;17(17):2786. doi:10.3390/cancers17172786
8. Riely GJ, Wood DE, Loo BW Jr, et al. Thymomas and thymic carcinomas, version 2.2025, NCCN clinical practice guidelines in oncology. J Natl Compr Canc Netw. 2025;23(6):255-269. doi:10.6004/jnccn.2025.0027
