Surgeon, Pathologist and Pathology Technician Effects on Nodal Yield after a Neck Dissection

Abstract

A minimum nodal count of 18 lymph nodes has been associated with improved survival after neck dissection and has been suggested as a head and neck cancer quality metric. Despite its critical importance, factors affecting nodal yield are poorly studied. In particular, the relative contribution of surgeons, pathologists, and pathology technicians has not been evaluated. The purpose of this study was to understand both patient and provider related factors that affect nodal yield after neck dissection for patients with oral cavity squamous cell carcinoma (OCSCC). This retrospective cohort study involved review of all adult patients with OCSCC undergoing primary neck dissection between 2000-2020 at an academic medical center. The outcome of interest was a continuous variable denoting the number of nodes removed per side during neck surgery. Surgeon and pathologist year of experience were calculated and represented in quartiles. A multilevel multivariable linear regression model was used to assess the association of surgeon/pathologist experience quartiles with nodal yield, controlling for patient age, comorbidity index, previous cancer, tumor grade, and clinical nodal status. The 508 patients included in our cohort were treated by 5 surgeons and 6 pathologists and involved 44 pathology technicians. Of these patients, 310 (61.0%) were male with a mean age of 63. Oral tongue primary tumors were 46.7% of the cohort, while 64.4% of patients had cT1-T2 tumors, and 65.2% were cN0. The mean nodal yield was 24.2 nodes. The ANOVA analysis revealed significant difference in mean nodal yield by surgeon (p-value = 0.03), pathologist (p-value<0.01) and pathology technician (p-value = 0.037). After accounting for patient-level characteristics and patient clustering by surgeon, increasing surgeon experience was found to be significantly associated with a higher nodal yield (joint significance of surgeon years of experience quartiles < 0.01). Specifically, when compared to surgeons with the least experience (1st quartile), those whose years of experience fell into the 2nd, 3rd, and 4th quartile removed 4.69 (95% CI: 0.97 to 7.92), 4.47 (95% CI: 0.33 to 7.87), and 7.37 (95% CI: 0.73 to 11.27) more lymph nodes. Meanwhile, there was no association between pathologist experience and nodal yield (joint significance of pathologist years of experience quartiles = 0.27). Additionally, previous cancer diagnosis and cN0 disease were significantly associated with lower nodal yield (all p-values = 0.02). This study demonstrates an independent association between increasing surgeon experience and higher nodal yields. Importantly, it also demonstrates that pathologists and pathology technicians contribute to the variation in nodal yield, and their contribution should not be overlooked in the implementation of a lymph node yield-based quality metric.