Pathology protocol increases lymph node yield in neck dissection for oral cavity squamous cell carcinoma

Identifying Opportunities to Deliver High-Quality Cancer Care Across a Health System: A Clinical Responsibility

OBJECTIVE

We examined process-related quality metrics for oral squamous cell carcinoma (OSCC) depending on treating facility type across a health system and region.

STUDY DESIGN

Retrospective in accordance with Strengthening the Reporting of Observational Studies in Epidemiology guidelines.

SETTING

Single health system and region.

METHODS

Patients with OSCC diagnosed between 2012 and 2018 were identified from tumor registries of 6 hospitals (1 academic and 5 community) within a single health system. Patients were categorized into 3 care groups: (1) solely at the academic center, (2) solely at community facilities, and (3) combined care at academic and community facilities. Primary outcome measures were process-related quality metrics: positive surgical margin rate, lymph node yield (LNY), adjuvant treatment initiation ≤6 weeks, National Comprehensive Cancer Network (NCCN)-guideline adherence.

RESULTS

A total of 499 patients were included: 307 (61.5%) patients in the academic-only group, 101 (20.2%) in the community-only group, and 91 (18.2%) in the combined group. Surgery at community hospitals was associated with increased odds of positive surgical margins (11.9% vs 2.5%, odds ratio [OR]: 47.73, 95% confidence interval [CI]: 11.2-275.86, P < .001) and lower odds of LNY ≥ 18 (52.8% vs 85.9%, OR: 0.15, 95% CI: 0.07-0.33, P < .001) relative to the academic center. Compared with the academic-only group, odds of adjuvant treatment initiation ≤6 weeks were lower for the combined group (OR: 0.30, 95% CI: 0.13-0.64, P = .002) and odds of NCCN guideline-adherent treatment were lower in the community only group (OR: 0.35, 95% CI: 0.18-0.70, P = .003).

CONCLUSION

Quality of oral cancer care across the health system and region is comparable to or better-than national standards, indicating good baseline quality of care. Differences by facility type and fragmentation of care present an opportunity for bringing best in-class cancer care across an entire region.

Prognostic Value of Lymph Node Yield, Lymph Node Density, and pN in Oral Cancer

OBJECTIVES

To investigate thresholds for lymph node yield (LNY), lymph node density (LND), and pN in patients with oral squamous cell carcinoma in relation to previous findings in the literature.

STUDY DESIGN

Retrospective register-based study.

SETTING

Copenhagen Oral Cavity Squamous Cell Carcinoma database.

METHODS

Appropriate thresholds for LNY, LND, and pN were determined by areas under the curve and subsequently subjected to multivariate analysis. Five-year overall survival and 3-year recurrence-free survival were determined by Kaplan-Meier survival curves.

RESULTS

In total, 413 patients diagnosed with oral squamous cell carcinoma were included. In the pN0 cohort, no superior/prognostic LNY cutoff values were detected. In the pN+ cohort, areas under the curve determined thresholds of LNY, LND, and pN to be 21 nodes, 5%, and 3 metastases, respectively. The 5-year overall survival was 52% for patients with LNY ≥21 vs 38% for patients with LNY <21 (hazard ratio [HR], 1.49; 95% CI, 1.05-2.11; P < .05), 60% for patients with LND ≤5% vs 38% for patients with LND >6% (HR, 1.63; 95% CI, 1.03-2.57; P < .05), and 43% for patients with pN <3 vs 26% for patients with pN ≥3 (HR, 1.40; 95% CI, 1.04-2.15; P < .05).

CONCLUSIONS

Increased nodal yield, decreased LND, and decreasing number of pN were associated with significantly improved survival outcomes. LNY might serve as a prognosticator of survival as well as a surgical quality indicator. LND may have implications as a tool in cancer staging and treatment planning.

Standard Lymphadenectomy for Esophageal and Lung Cancer: Variability in the Number of Examined Lymph Nodes Among Pathologists and Its Survival Implication

AIM

We compared variability in number of examined lymph nodes between pathologists and analyzed survival implications in lung and esophageal cancer after standardized lymphadenectomy.

METHODS

Outcomes of 294 N2 dissected lung cancer patients and 132 2-field dissected esophageal cancer patients were retrospectively examined. The primary outcome was difference in reported lymph node count among pathologists. Secondary outcomes were overall and disease-specific survival related to this count and survival related to the 50% probability cut-off value of detecting metastasis based on the number of examined lymph nodes.

RESULTS

The median number of examined lymph nodes in lung cancer was 13 (IQR 9-17) and in esophageal cancer it was 22 (18-29). The pathologist with the highest median number of examined nodes had > 50% higher lymph node yield compared with the pathologist with the lowest median number of nodes in lung (15 vs. 9.5, p = 0.003), and esophageal cancer (28 vs. 17, p = 0.003). Survival in patients stratified by median reported lymph node count in both lung (adjusted RMST ratio < 14 vs. ≥ 14 lymph nodes 0.99, 95% CI 0.88-1.10; p = 0.810) and esophageal cancer (adjusted RMST ratio < 25 vs. ≥ 25 lymph nodes 0.95, 95% CI 0.79-1.15, p = 0.612) was similar. The cut-off value for 50% probability of detecting metastasis by number of examined lymph nodes in lung cancer was 15.7 and in esophageal cancer 21.8. When stratified by this cut-off, no survival differences were seen.

CONCLUSION

The quality of lymphadenectomy based on lymph node yield is susceptible to error due to detected variability between pathologists in the number of examined lymph nodes. This variability in yield did not have any survival effect after standardized lymphadenectomy.

Assessing Prognostic Value of Quantitative Neck Dissection Quality Measures in Patients With Clinically Node-Negative Oral Cavity Squamous Cell Carcinoma

Importance

In clinically localized (T1-2) oral cavity squamous cell carcinoma (OCSCC), regional lymph node metastasis is associated with a poor prognosis. Given the high propensity of subclinical nodal disease in these patients, upfront elective neck dissections (END) for patients with clinically node-negative disease are common and associated with better outcomes. Unfortunately, even with this risk-adverse treatment paradigm, disease recurrence still occurs, and our understanding of the factors that modulate this risk and alter survival have yet to be fully elucidated.

Objective

To investigate the prognostic value of lymph node yield (LNY), lymph node ratio (LNR), and weighted LNR (wLNR) in patients with clinically node-negative T1-2 OCSCC.

Design, Setting, and Participants

In this cohort study, data were collected retrospectively from 7 tertiary care academic medical centers. Overall, 523 patients with cT1-2N0 OCSCC who underwent elective neck dissections after primary surgical extirpation were identified.

Exposures

Lymph node yield was defined as the number of lymph nodes recovered from elective neck dissection. Lymph node ratio was defined as the ratio of positive nodes against total LNY. Weighted LNR incorporated information from both LNY and LNR into a single continuous metric.

Main Outcomes and Measures

Locoregional control (LRC) and disease-free survival (DFS) were both evaluated using nonparametric Kaplan-Meier estimators and semiparametric Cox regression.

Results

On multivariable analysis, LNY less than or equal to 18 lymph nodes was found to be significantly associated with decreased LRC (aHR, 1.53; 95% CI, 1.04-2.24) and DFS (aHR, 1.46; 95% CI, 1.12-1.92) in patients with pN0 disease, but not those with pN-positive disease. Importantly, patients with pN0 disease with LNY less than or equal to 18 and those with pN1 diseasehad nearly identical 5-year LRC (69.7% vs 71.4%) and DFS (58.2% vs 55.7%). For patients with pN-positive disease, LNR greater than 0.06 was significantly associated with decreased LRC (aHR, 2.66; 95% CI, 1.28-5.55) and DFS (aHR, 1.65; 95% CI, 1.07-2.53). Overall, wLNR was a robust prognostic variable across all patients with cN0 disease, regardless of pathologic nodal status. Risk stratification via wLNR thresholds demonstrated greater optimism-corrected concordance compared with American Joint Committee on Cancer (AJCC) 8th edition nodal staging for both LRC (0.61 vs 0.57) and DFS (0.61 vs 0.58).

Conclusions and Relevance

Movement toward more robust metrics that incorporate quantitative measures of neck dissection quality and regional disease burden, such as wLNR, could greatly augment prognostication in cT1-2N0 OCSCC by providing more reliable and accurate risk estimations.

Prognostic value of lymph node involvement in oral squamous cell carcinoma

Objectives

Different parameters have been identified in patients with oral squamous cell carcinomas (OSCC) that have a serious impact on survival, including residual tumour and extracapsular spread. Moreover, other factors, including the lymph node ratio (LNR) and lymph node yield (LNY), have been suggested as prognostic markers.

Material and methods

This retrospective study included patients diagnosed with OSCC and cervical lymph node metastases during the years 2010–2020. Patients’ records were evaluated regarding lymph node status, final therapy regime, tumour recurrence, time to death, tumour association with death, disease-free survival (DSF), and overall survival (OS).

Results

In 242 patients with a mean age of 63.57 ± 11.24 years, treated either by selective neck dissection (SND; n = 70) or by modified radical neck dissection (MRND; n = 172), 5772 lymph nodes were detected. The LNR and LNY were identified as independent risk factors in OS and DFS. The optimal cut-off point for the LNY was ≥ 17 lymph nodes in the SND and ≥ 27 lymph nodes in the MRND group.

The metastatic lymph node clearance (MLNC) was established as a score to relate the LNR and LNY to the extent of lymph node removal. Survival analysis showed statistically significant differences among score levels.

Conclusions

As information about the extent of nodal dissection is excluded from LNR and LNY, we propose the use of a new scoring system comprising individual cut-off values for LNY and LNR with regard to the extent of neck dissection.

Clinical Relevance

MLNC might help to identify high-risk OSCC patients with metastatic lymph nodes.

CT for estimating adequacy of lymph node dissection in patients with squamous cell carcinoma of the head and neck

Background

Indices obtained from lymph node dissection specimens, specifically lymph node yield (LNY) and lymph node ratio (LNR), have prognostic significance in the setting of head and neck squamous cell carcinoma (HNSCCa). However, there are currently no validated tools to estimate adequacy of planned lymph node dissection using preoperative data. The present study sought to evaluate CT-derived estimates of lymphatic tissue volumes as a preoperative tool to guide cervical node dissection.

Methods

Fifteen cervical lymph node dissections were performed in 14 subjects with HNSCCa. Preoperative CT-derived estimates of lymphatic tissue volumes were compared with gross pathology tissue volume estimates and pathologically-determined LNY.

Results

Resected tissue volume (calculated using the triaxial ellipsoid method) correlates with CT-derived preoperative lymphatic volume estimates (r = 0.74, p = 0.003) while LNY does not(r = − 0.12, p = 0.67). When excluding pathologically enlarged lymph nodes (“refined” data), a negative correlation was observed between refined CT-derived volume estimates and refined LNY (r = − 0.65, p = 0.009).

Conclusion

In the setting of cervical lymph node dissection, CT-derived lymphatic volume estimates correlate with resected tissue volume, but refined CT-derived volume estimates correlate negatively with refined LNY.

Trial registration

Retrospectively registered.

Level of evidence

4

Lymph node yield in treatment naïve cases of head and neck squamous cell carcinoma: en bloc lymphadenectomy versus level-by-level dissection

BACKGROUND

Lymph node yield is an important prognostic factor in head and neck squamous cell carcinoma. Variability in neck dissection sampling techniques has not been studied as a determinant of lymph node yield.

METHODS

This retrospective study used lymph node yield and average nodes per level to compare level-by-level and en bloc neck dissection sampling methods, in primary head and neck squamous cell carcinoma cases operated between March 2017 and February 2020.

RESULTS

From 123 patients, 182 neck dissections were analysed, of which 133 were selective and the rest were comprehensive: 55 had level-by-level sampling and 127 had undergone en bloc dissection. The level-by-level method yielded more nodes in all neck dissections combined (20 vs 17; p = 0.097), but the difference was significant only for the subcohort of selective neck dissection (18.5 vs 15; p = 0.011). However, the gain in average nodes per level achieved by level-by-level sampling was significant in both groups (4.2 vs 3.33 and 4.4 vs 3, respectively; both p < 0.001).

CONCLUSION

Sampling of cervical lymph nodes level-by-level yields more nodes than the en bloc technique. Further studies could verify whether neck dissection sampling technique has any impact on survival rates.

Nodal yield and topography of nodal metastases from oral cavity squamous cell carcinoma - An audit of 1004 cases undergoing primary surgical resection

OBJECTIVES

Nodal metastasis is an important prognostic factor in oral squamous cell carcinoma (OSCC). Detailed topographic study of metastasis can guide surgical and adjuvant radiation treatment protocols.

METHODS

Retrospective analysis of distribution of nodal spread was done by auditing pathology records of 1004 patients who underwent primary surgical management at our center.

RESULTS

The median nodal yield was 41 (range of 9-166) nodes, per patient. Metastasis was present in 42.9% patients, of which 52.3% demonstrated extranodal extension. Reclassification by AJCC8 criteria resulted in up-staging in 35.6% patients (pN1, pN2a, pN2b, pN2c, pN3a and pN3b in 13.1%, 3.7%, 6.9%, 0.9%, 0%, 18.1% respectively). Ipsilateral levels Ib and IIa were involved in a quarter of patients each, while IIb, IV and V were involved in < 4%, 3% and 1% of patients, respectively. Contralateral nodal metastasis was present in 5.4%. Skip metastases to level IV were 2.2% and 1.2% for tongue and gingivobuccal primaries. Tongue primaries had a lower likelihood of involving level Ib, but higher of level IIa and III, compared to gingivobuccal primaries, and a lower likelihood of extranodal extension. Primary site did not influence nodal metastasis to levels IIb, IV or V, but other factors like lymphovascular invasion, pT stage and margin status had an influence.

CONCLUSION

This large series with high nodal yield, shows low level of metastasis to level IIb, IV and V, which can help modify future guidelines for extent of surgery and avoid targeted adjuvant radiation to specific levels.