Putting the needle before the knife: Minimally invasive approaches to diagnostic lymph node biopsy in melanoma

Recent advances in the systemic treatment of advanced melanoma have prompted reevaluation of treatment paradigms. This reassessment has included clinical trials to test these new efficacious therapies in the neoadjuvant setting for surgically resectable earlier stage metastatic disease.

The standard of care for resectable, clinically evident, nodal metastatic melanoma remains therapeutic lymph node dissection, followed by consideration of adjuvant therapy. Percutaneous needle biopsy of the suspicious lymph node remains the optimal method for diagnostic evaluation independent of whether neoadjuvant therapy (ideally on clinical trial) or upfront surgery is planned for the resectable nodal disease. However, widespread variation with respect to how clinicians approach diagnostic lymph node biopsy for suspicious peripheral lymphadenopathy persists.

Improving value-based care

As surgeons, we are entrusted to perform excisional lymph node biopsies when indicated. At the same time, we have the opportunity to improve patient care and outcomes by recognizing that percutaneous needle biopsy should be the first step in diagnosis, with excisional lymph node biopsy reserved for diagnostic dilemmas and only approached after careful consideration of incision placement for subsequent therapeutic oncologic operation.

The differential diagnosis of peripheral adenopathy in adults is extensive, but for patients with a prior history or concurrent diagnosis of melanoma and clinically apparent or radiologically evident adenopathy, malignancy should be suspected. Ideally, the appropriate and guideline-concordant approach to suspicious peripheral adenopathy is to first perform a history focused on constitutional symptoms, past cancer history, and a physical exam directed to the skin and peripheral nodal basins.

When malignancy is a possibility, or when adenopathy is persistent after a short period of observation, the next best step is an ultrasound-guided percutaneous fine needle aspiration (FNA) or core needle biopsy (CNB) (see Figure 1).¹ This approach has been used effectively to diagnose soft-tissue sarcoma and breast cancer for decades.^2-5 This rapid, cost-effective, and well-tolerated approach usually can establish a diagnosis. Numerous studies have confirmed the high sensitivity and specificity of FNA for melanoma metastatic to lymph nodes, with reports of up to 97 percent and 99 percent, respectively.⁶ Genetic testing can be performed on FNA or CNB of bulky nodal disease.⁷

Figure 1. Ultrasound-guided needle biopsy of axillary lymph node

Even when a melanoma diagnosis is unanticipated—for example, clearly pathologic single basin adenopathy in the absence of a prior melanoma diagnosis—this same approach is warranted. For example, CNB can be used for subtyping of lymphoma sufficient to guide appropriate treatment in three-quarters of patients.⁸ This approach is aligned with the trend over time across all disciplines of surgery of a shift from a diagnostic to a therapeutic indication for operation whenever possible.

Diagnostic excisional lymph node biopsy is generally regarded as a straightforward and low-risk procedure; however, it may not be the optimal first step for diagnosing suspicious peripheral adenopathy for several reasons, including sparing patients a potentially unnecessary operation; the higher cost of an operation versus a quick office procedure; creation of an incision that often is suboptimal or inappropriately placed for future therapeutic lymphadenectomy incisions; disruption of the operative field (lymphatic basin) prior to therapeutic operation; and the potential morbidity of an operation, including bleeding, infection, seroma, lymphocele, lymphatic fistula, neuropathy, and pain, versus the extremely low risk of percutaneous FNA or CNB. Furthermore, when neoadjuvant systemic therapy is administered, percutaneous needle biopsy facilitates testing the response to treatment, whereas it cannot be assessed accurately following excisional biopsy if the node has been removed.

An opportunity worth exploring

This approach presents another opportunity for surgical practice harmonization so that all patients, regardless of where or by whom they are seen, are recommended for a minimalistic approach to the diagnosis of suspicious lymphadenopathy as the first step in care. As surgeons have done and continue to do in multiple other areas, surgeons should embrace best clinical practice and resolve practice disparities in the diagnosis of adenopathy and thereby improve patient care.

References

1. National Comprehensive Cancer Network. Clinical Practice Guidelines: Melanoma v2.2019. Available at: www.nccn.org/professionals/physician_gls/pdf/cutaneous_melanoma.pdf. Accessed June 9, 2019.
2. Heslin MJ, Lewis JJ, Woodruff JM, Brennan MF. Core needle biopsy for diagnosis of extremity soft tissue sarcoma. Ann Surg Oncol. 1997;4(5):425-431.
3. National Comprehensive Cancer Network. Clinical Practice Guidelines: Soft Tissue Sarcoma v2.2019. Available at: www.nccn.org/professionals/physician_gls/pdf/sarcoma.pdf. Accessed June 9, 2019.
4. Ough M, Velasco J, Hieken TJ. A comparative analysis of core needle biopsy and final excision for breast cancer: Histology and marker expression. Am J Surg. 2011;201(5):685-687.
5. National Comprehensive Cancer Network. Clinical Practice Guidelines: Breast Cancer Screening and Diagnosis v1.2019. Available at: www.nccn.org/professionals/physician_gls/pdf/breast-screening.pdf. Accessed June 9, 2019.
6. Hall BJ, Schmidt RL, Sharma RR, Layfield LJ. Fine-needle aspiration cytology for the diagnosis of metastatic melanoma: Systematic review and meta-analysis. Am J Clin Pathol. 2013;140(5):635-642.
7. Bohelaya G, Battistellab M, Pagesa C, et al. Ultrasound-guided core needle biopsy of superficial lymph nodes: An alternative to fine-needle aspiration cytology for the diagnosis of lymph node metastasis in cutaneous melanoma. Melanoma Res. 2015;25(6):519-527.
8. Frederiksen JK, Sharma M, Casulo C, Burack WR. Systematic review of the effectiveness of fine-needle aspiration and/or core needle biopsy for subclassifying lymphoma. Arch Pathol Lab Med. 2015;139(2):245-251.