Value of ultrasound guidance in cytopathologist-performed fine-needle aspirations of palpable lesions

Introduction

Fine-needle aspirations (FNAs) of palpable masses are often performed by cytopathologists without ultrasound (US) guidance. Nonetheless, variations in the actual depth of palpable masses lead to occasional challenges. US guidance allows cytopathologists to visualize the mass and guide needle placement. This study retrospectively addressed the utility of US by comparing FNAs performed by cytopathologists on palpable masses with and without US guidance.

Materials and methods

Cytopathologist-performed FNAs with and without US guidance from March 1, 2013 to July 1, 2014 were identified. The number of passes, location of lesions, and interpretations were recorded. Available slides were reviewed to determine the proportion of passes that contained diagnostic cellular material and cases in which diagnostic material was present on the first needle pass.

Results

In this study, 134 palpation-guided FNAs and 118 US-guided FNAs were analyzed. The percentage of nondiagnostic cases was significantly lower for US-guided FNAs (2.5%) than for palpation-guided FNAs (12.7%; P = 0.004). The average number of needle passes was significantly lower for US-guided FNAs (2.9) than for palpation-guided FNAs (3.6; P = 0.0002). Twenty-two of 118 of US-guided FNAs (18.6%) and 6 of 134 palpation-guided FNAs (4.5%) were completed after only a single pass (P = 0.0008). The percentage of passes with diagnostic material was significantly higher for US-guided FNAs (73.6% versus 60%; P = 0.0002).

Conclusions

For palpable masses, US-guidance adds value to cytopathologists in obtaining diagnostic cellular material more often on the first pass and with fewer passes overall than by palpation alone. This has a potentially beneficial impact on patient care owing to the increased precision and accuracy of needle guidance with ultrasonography.

Introduction

Fine-needle aspirations (FNAs) are routinely performed by cytopathologists on palpable masses without ultrasound (US) guidance. Nonetheless, the palpable lesions of interest can occasionally be difficult to target because of variations in their actual depth. Because palpability does not necessarily equate to superficiality, there can be instances during which initial needle passes reveal no diagnostic material due to insufficient depth of penetration by the needle. The use of ultrasonography allows the performer of the FNA to visualize a mass in relation to the surrounding tissue including major vascular structures. By ascertaining the depth and location of the lesion, US can be instrumental in guiding the placement of the needle during an FNA pass.

US-guided FNAs are often performed by a variety of clinical care providers such as radiologists and clinicians and over the past half century, US-guided FNA has become increasingly popular with respect to palpable FNA.¹ Although the literature on cytopathologist-performed US-guided FNAs is relatively sparse, the use of ultrasonography is becoming increasingly adopted by the cytopathology community.2, 3, 4, 5, 6 These studies have addressed both palpable and nonpalpable masses at various anatomic sites, including lymph nodes, breast, thyroid, parathyroid, and salivary glands. Advantages of a cytopathologist-led US-guided FNA service include increased precision of needle targeting, lower sample inadequacy rates, real-time feedback on the efficacy of cell acquisition via rapid on-site evaluation (ROSE) of adequacy, preliminary diagnostic assessment, judicious procurement and triaging of additional material for necessary or anticipated ancillary studies based on that assessment, and, ultimately, timely diagnoses for efficient patient management. A recent systematic review has suggested that the best results are obtained with a “one-stop cytopathologist-led FNA service” for head and neck lesions.¹

At our institution, cytopathologists have traditionally performed palpable FNAs in our FNA clinic until November 1, 2013, during which there was a transition to exclusively performing US-guided FNAs in our clinic. ROSE is employed for all of our cytopathologist-performed FNAs. In this study, we sought to retrospectively examine and compare the following parameters in cytopathologist-performed US-guided and palpation-guided FNAs: nondiagnostic rate, average number of needle passes for the given procedures, completion of the procedure after a single needle pass, and percentage of passes with diagnostic material. To our knowledge, this is the first study that addresses the comparative value of cytopathologists using US-guidance versus palpation alone during FNAs of palpable masses in this manner.